Forum: War Ensemble BBS

DAY1SVR: Day 1 Convective Outlook

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 05:40:22 2026

ACUS01 KWNS 080539
SWODY1
SPC AC 080538

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Tue Sep 08 2026

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
IOWA AND EASTERN NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly severe wind gusts
appear possible across portions of Iowa and eastern Nebraska Tuesday
afternoon and evening. More sporadic occurrences of severe winds and
large hail may occur from portions of the upper Midwest into the
central Plains.

...Synopsis...

An intense upper low moving into southern SK late this evening will
continue northeast through central MB into northern ON ahead of a
secondary short-wave trough tracking from the northern Rockies into
the northern Plains. A belt of enhanced mid/upper-level winds will
be maintained between those features from the northern High Plains
into the upper Great Lakes. At the surface, a cold front will
advance through the eastern Dakotas and upper MS Valley with the
trailing extension of the boundary moving more slowly southeast
through the mid-MO Valley and central High Plains.

...Central Plains into the upper Midwest...

Clusters of thunderstorms are likely to be ongoing at 12Z Tuesday
from portions of the mid-MO Valley into the upper Midwest within a
zone of warm advection and moisture transport along a nocturnal
low-level jet (LLJ). Showers and storms may linger through the
morning across parts of WI and the U.P. of MI, limiting the degree
of air mass destabilization and associated severe weather risk
during the afternoon. Farther to the southwest from IA through
eastern and southern NE into northern KS, stronger daytime heating
on the southern fringe of lingering mid/high-level cloudiness will
contribute to a well-mixed boundary layer, featuring steep low-level
lapse rates. When combined with boundary-layer dewpoints in the 60s
to low/mid 70s F, the air mass is expected to become moderately to
strongly unstable by late afternoon with MLCAPE of 2000-3000 J/kg.

In the absence of appreciable height falls/large-scale forcing for
ascent, convergence along the front and any preceding confluence
zones/outflow boundaries is expected to foster a gradual increase in
storm coverage and intensity by mid to late afternoon amidst the
destabilizing air mass. The strongest deep-layer shear is expected
to be displaced to the north of the effective warm sector with
around 30-35 kt forecast along the frontal zone. A largely parallel shear-vector orientation with the front suggests that initial storms
should grow upscale into line segments or a broken band with an
associated risk for severe wind gusts from mid afternoon through
evening. Isolated occurrences of marginally severe hail are
possible; however, poor mid-level lapse are expected to limit the
overall threat. The 00Z models do indicate some LLJ enhancement over
central IA by late afternoon into evening, resulting in a corridor
of stronger low-level shear. While a brief tornado or two are
possible, a more robust threat is expected to be limited by largely outflow-dominant storms.

..Mead/Chalmers.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 12:33:14 2026

ACUS01 KWNS 081233
SWODY1
SPC AC 081231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Tue Sep 08 2026

Valid 081300Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
CENTRAL IOWA AND FAR EASTERN NEBRASKA...

...SUMMARY...
Widely scattered severe storms capable of mainly severe wind gusts
appear possible across portions of Iowa and eastern Nebraska Tuesday
afternoon and evening. More sporadic occurrences of severe winds and
large hail may occur from portions of the upper Midwest into the
central Plains.

...Central Plains into the upper Midwest...
An extensive low-level jet is currently in place from the southern
High Plains through the Upper Midwest. Warm-air advection associated
with this feature is contributing to showers and thunderstorms from
eastern NE through WI and into western Upper MI. This activity is
forecast to gradually shift northeastward this morning while the
embedded storms also gradually diminish in strength. These showers
and thunderstorms, and associated warm low to mid-level
temperatures, are expected to limit destabilization across much of
WI and Upper MI.

Some moderate buoyancy is possible by the early afternoon across MN,
just ahead of a cold front pushing eastward into the region.
Lingering convective inhibition will likely limit convective
initiation, and considerable uncertainty exists regarding
thunderstorm coverage. This uncertainty precludes introducing any
severe probabilities, but the combination of moderate buoyancy and
strong deep-layer shear over the region would support some severe
potential with any updrafts that persist and mature.

Farther south and west (i.e. from IA through eastern/southern NE
into northern KS), stronger daytime heating will contribute to a
well-mixed boundary layer, characterized by steep low-level lapse
rates and dewpoints in the 60s to low/mid 70s F. This air mass is
expected to become moderately to strongly unstable by late afternoon
with MLCAPE of 2000-3000 J/kg. Thunderstorm development is expected
as the southeastward-progressing cold front interacts with this
destabilized and buoyant airmass. The stronger vertical shear will
be displaced north/northeast of the greater buoyancy, but 30 to 35
kt of effective bulk shear is still sufficient for some storm
organization. A largely parallel shear-vector orientation with the
front suggests that initial storms should grow upscale quickly into
line segments or broken bands, with some tendency for undercutting
as well. Even so, a few damaging wind gusts will be possible from
mid afternoon through evening. The low-level jet will increase again
from western KS through central IA this evening resulting in a
corridor of stronger low-level shear. This low-level shear will
support a low-probability tornado risk, but a more robust threat is
expected to be limited by largely outflow-dominant and/or elevated
storms.

...CO Plains into western KS...
Thunderstorm development appears likely across the higher terrain of
central CO as the mid-level flow veers more westerly during the late
afternoon. Moist post-frontal northerly low-level flow is expected
across the CO Plains and western KS this evening, which could result
in enough buoyancy to maintain modest intensity as the central CO
storms progress eastward. High-based storm character and prevailing
steep low-level lapse rates may result in a few stronger gusts as
this cluster moves eastward into western KS.

..Mosier/Lyons.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 16:17:44 2026

ACUS01 KWNS 081617
SWODY1
SPC AC 081615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1115 AM CDT Tue Sep 08 2026

Valid 081630Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST NEBRASKA ACROSS PARTS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa and eastern Nebraska this afternoon
and evening.

...NE/IA...
A broad upper ridge remains over much of the central/southern US,
with moderately strong westerly flow over the northern tier of
states. A baroclinic zone extends across southern NE into central
IA. This feature will be sharpened by differential heating through
the day, and will be the focus for afternoon and evening
thunderstorm development. The strongest cells will be near a 20-30
knot southwesterly low-level jet where warm advection and lift will
aid in convective initiation. Sufficient deep-layer shear will
promote supercell and eventual bowing structures, with damaging
winds be the main concern. Most CAM solutions suggest the majority
of convection will be just north of the surface boundary, which may
limit the overall severe threat. Also, weak mid-level lapse rates
and warm temperatures aloft will tend to diminish the hail risk.

...CO/KS...
Farther southwest, hot surface conditions will result in a deeply
mixed boundary layer. Scattered high-based showers and
thunderstorms are expected to form from eastern CO into
western/central KS, with gusty and occasionally damaging wind gusts
possible.

..Hart/Guyer.. 09/08/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 8 19:49:14 2026

ACUS01 KWNS 081949
SWODY1
SPC AC 081947

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Tue Sep 08 2026

Valid 082000Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM SOUTHEAST NEBRASKA ACROSS PARTS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa and eastern Nebraska this afternoon
and evening.

...20Z Update...
The ongoing forecast remains on track and no changes are needed.

..Wendt.. 09/08/2026

.PREV DISCUSSION... /ISSUED 1115 AM CDT Tue Sep 08 2026/

...NE/IA...
A broad upper ridge remains over much of the central/southern US,
with moderately strong westerly flow over the northern tier of
states. A baroclinic zone extends across southern NE into central
IA. This feature will be sharpened by differential heating through
the day, and will be the focus for afternoon and evening
thunderstorm development. The strongest cells will be near a 20-30
knot southwesterly low-level jet where warm advection and lift will
aid in convective initiation. Sufficient deep-layer shear will
promote supercell and eventual bowing structures, with damaging
winds be the main concern. Most CAM solutions suggest the majority
of convection will be just north of the surface boundary, which may
limit the overall severe threat. Also, weak mid-level lapse rates
and warm temperatures aloft will tend to diminish the hail risk.

...CO/KS...
Farther southwest, hot surface conditions will result in a deeply
mixed boundary layer. Scattered high-based showers and
thunderstorms are expected to form from eastern CO into
western/central KS, with gusty and occasionally damaging wind gusts
possible.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 00:38:18 2026

ACUS01 KWNS 090038
SWODY1
SPC AC 090036

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0736 PM CDT Tue Sep 08 2026

Valid 090100Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS PORTIONS OF IOWA...

...SUMMARY...
A few severe storms capable of mainly severe wind gusts appear
possible across portions of Iowa this evening.

...Discussion...
Widely scattered thunderstorm activity continues across the surface
boundary extending from portions of central/southern Iowa into
southern Nebraska and northern/western Kansas. A more organized
cluster is ongoing across portions of south-central Iowa. This
cluster will continue to pose a wind threat for the next couple of
hours before eventually moving southeast into less favorable air
across southeastern Iowa/western Illinois. Additional convection
will evolve overnight with the increasing low-level jet across
central Kansas into southeastern Nebraska and southern Iowa. This
will pose at least some potential for small hail and strong to
severe wind.

Across Colorado, scattered convection is ongoing near the foothills
of the Front Range. Time lagged HRRR/RRFS guidance continues to
suggest that this evolves into a cluster with potential for strong
to severe wind to continue downstream this evening. Though moisture
is limited, very warm surface temperatures and steep low to
mid-level lapse rates are supporting at least marginally unstable
conditions downstream.

..Thornton.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 05:43:46 2026

ACUS01 KWNS 090543
SWODY1
SPC AC 090541

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 AM CDT Wed Sep 09 2026

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO
INTO WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley on Wednesday. A more
organized severe weather threat is expected from eastern Ohio to
western New York.

...Synopsis...
A belt of enhanced mid-level flow will move through the broad
upper-level trough across Ontario, overspreading the Great Lakes
into Upstate New York and Quebec. A cold front will extend from a
deep surface low across northern Ontario south through the Upper
Midwest and into the central High Plains. Isolated to widely
scattered thunderstorm activity is expected near the surface trough
across the Ohio Valley into the Northeast and along the front from
the Midwest to the central High Plains.

...Eastern Ohio into western New York...
Across the eastern Ohio Valley into portions of the Northeast,
strengthening mid-level flow will overspread the region with
thunderstorms developing along the cold front and pre-frontal
surface trough. Upper 60s to 70s dew points and filtered daytime
heating will yield moderate instability amid ample deep layer shear
for organization. Mode will likely be a mix of multi-cell clusters
and transient supercells, with potential for damaging wind.
Generally weak lapse rate profiles and quick mode transition to
clusters/linear segments should limit hail and tornado potential.
Nonetheless, as the low-level jet increases into the afternoon and
clockwise curvature increases in hodographs a tornado may be
possible.

...Ohio Valley to the Midwest and the central Plains...
Morning convection will be likely across much of the
Midwest/Mid-Missouri Valley into the northwestern Ohio Valley.
Remnant shower activity/cloud cover will likely limit severe
potential with northern extent. Nonetheless, isolated to widely
scattered thunderstorm activity is expected to develop by the
afternoon along the front and remnant outflow from the eastern Ohio
Valley through portions of the Midwest and into the central Plains.
Flow will be fairly weak across the central Plains, with generally a
marginal damaging wind threat with multi-cell clusters as daytime
heating steepens low-level lapse rates amid deeply mixed profiles.
Slightly better flow aloft may favor a more focused cluster across
the Mid-Mississippi Valley into western Kentucky/Tennessee.

..Thornton/Chalmers.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 12:43:48 2026

ACUS01 KWNS 091243
SWODY1
SPC AC 091241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Wed Sep 09 2026

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL OHIO
FROM WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today. A more organized
severe weather threat is expected from eastern Ohio to western New
York.

...Synopsis...
Early-morning satellite imagery show broad upper troughing from the
Pacific Northwest/British Columbia through the Upper Great Lakes and
Ontario. Several shortwave troughs are embedded within this larger
upper troughing, including one moving into northern MN and another
farther north across far northwestern Ontario. A belt of moderate to
strong mid-level westerly/southwesterly flow extends between the
base of these two waves. Expectation is the southern wave to move
quickly eastward through the Upper Great Lakes and Ontario,
accompanied by mid-level jet max.

Surface analysis places a occluded low over far northwestern
Ontario, with a cold front extending southward into western Upper MI
and then back southwestward through central NE. An outflow-augmented pre-frontal trough precedes this front, extending from a low in
southwest Lower MI to another low over northeast KS to another over
far southwest KS/far southeast CO. Both the cold front and
pre-frontal trough are expected to progress modestly
southward/southeastward today. Two corridors of relatively higher
thunderstorm coverage are anticipated this afternoon/evening, one
from eastern OH into western PA/western NY and the other farther
southwest from the Lower MO Valley into the TX/OK Panhandles.

...Central Ohio into western New York...
Moist low-levels are already in place from the OH Valley into
western PA and NY, with recent surface analysis sampling upper 60s
dewpoints in central OH decreasing to the low/mid 60s across western
PA and western NY. This moist airmass is expected to destabilize
amid modest low-level moisture advection and filtered insolation,
ahead of a convectively augmented vorticity maximum. With the cold
front still well to the northwest, this vorticity maximum will be
the primary impetus for thunderstorm development, augmenting the
weak low-level confluence along the weak pre-frontal trough. A
predominately linear/clustered storm mode is anticipated, but
strengthening mid-level flow will support effective bulk shear from
30 to 40 kt, which could support some more persist/organized line
segments. Damaging gusts are the primary risk with any of these more
organized segments. Low-level hodographs do show some notable
curative, particularly from western PA into western NY after 00Z,
amid a strengthening low-level jet. As such, there is a
low-probability tornado risk is these areas.

...Lower OH and MO Valleys into the TX/OK Panhandles...
Thunderstorm coverage is gradually expected to increase across the
region this afternoon and evening, beginning near a surface low move
across the Lower MO Valley before expanding back southwestward along
the southward-progressing front. The stronger vertical shear will be
displace north of the front, and a largely disorganized,
outflow-dominant storm mode is anticipated. Slightly better flow
aloft may favor a more focused cluster across the Mid-Mississippi
Valley into western Kentucky/Tennessee. Steep low-level lapse rates
and high cloud bases could support strong gusts from the Lower MO
Valley into the TX/OK Panhandles.

...Southern AZ...
Afternoon thunderstorms are expected over the higher terrain near
the southern AZ/NM border. There is some potential this activity
progresses westward into the lower elevations of southern AZ.
However, upper ridging will be centered over this region and
vertical shear will be weak, resulting in slow storm motion and
disorganized, outflow-dominant structures. A few strong gusts could
result from any more persistent updrafts.

..Mosier/Lyons.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 16:29:34 2026

ACUS01 KWNS 091629
SWODY1
SPC AC 091627

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Wed Sep 09 2026

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM CENTRAL OHIO INTO NORTHWEST PENNSYLVANIA AND WESTERN
NEW YORK....

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today.

...OH/PA/NY...
A fast-moving shortwave trough now over WI/IL will track eastward
today across the Great Lakes region. At the surface, the primary
baroclinic currently extends from Lake Erie into OH/IN and will move
eastward and be the focus for scattered afternoon thunderstorms.
Strong heating and dewpoints in the 70s across much of OH and
western PA will result in moderate CAPE values and steep low-level
lapse rates. Sufficient deep-layer shear will promote organized
storms with some bowing structures expected, capable of locally
damaging wind gusts. This activity will spread into western
NY/northwest PA by early evening before weakening.

...IN/IL/MO...
The storms that form over OH will zipper southwestward along the
boundary into a pocket of ample CAPE/moisture over parts of southern
IN/IL into southern MO. Winds aloft in this area will be weaker,
with less overall organization of storms. Nevertheless, a few
storms may occasionally produce damaging wind gusts.

...TX/OK/KS...
Widely scattered slow-moving afternoon thunderstorms will pose a
risk of gusty/damaging winds in a hot/humid surface air mass.

..Hart/Guyer.. 09/09/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 9 20:04:48 2026

ACUS01 KWNS 092004
SWODY1
SPC AC 092002

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0302 PM CDT Wed Sep 09 2026

Valid 092000Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM CENTRAL OHIO INTO NORTHWEST PENNSYLVANIA AND WESTERN
NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today.

...20Z Update...
Minor changes were made to the general thunderstorms forecast based
on observations and recent guidance. Severe probabilities remain
unchanged, however. See the previous discussion for additional
information.

..Wendt.. 09/09/2026

.PREV DISCUSSION... /ISSUED 1127 AM CDT Wed Sep 09 2026/

...OH/PA/NY...
A fast-moving shortwave trough now over WI/IL will track eastward
today across the Great Lakes region. At the surface, the primary
baroclinic currently extends from Lake Erie into OH/IN and will move
eastward and be the focus for scattered afternoon thunderstorms.
Strong heating and dewpoints in the 70s across much of OH and
western PA will result in moderate CAPE values and steep low-level
lapse rates. Sufficient deep-layer shear will promote organized
storms with some bowing structures expected, capable of locally
damaging wind gusts. This activity will spread into western
NY/northwest PA by early evening before weakening.

...IN/IL/MO...
The storms that form over OH will zipper southwestward along the
boundary into a pocket of ample CAPE/moisture over parts of southern
IN/IL into southern MO. Winds aloft in this area will be weaker,
with less overall organization of storms. Nevertheless, a few
storms may occasionally produce damaging wind gusts.

...TX/OK/KS...
Widely scattered slow-moving afternoon thunderstorms will pose a
risk of gusty/damaging winds in a hot/humid surface air mass.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 00:42:24 2026

ACUS01 KWNS 100042
SWODY1
SPC AC 100040

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 PM CDT Wed Sep 09 2026

Valid 100100Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS A PORTION OF THE
UPPER OHIO VALLEY...

...SUMMARY...
Isolated severe storms capable of mainly damaging wind gusts will
remain possible through late evening from the upper Ohio Valley into
the southern Plains.

...Upper Ohio Valley/Lower Great Lakes...

Scattered thunderstorms are ongoing this evening along and ahead of
a cold front from north-central PA into central OH within a moist
air mass with the 00Z Pittsburgh sounding indicating MLCAPE of
around 1000 J/kg. Moreover, the corresponding wind profile exhibited
relatively strong low-level and deep-layer shear with effective SRH
of around 250 m2/s2 and effective bulk shear of around 40 kt. So,
while lapse rates and resultant instability are expected to weaken
with the loss of daytime heating, the kinematic environment will
remain supportive of transient supercell and bowing structures
capable of locally damaging wind gusts and perhaps a tornado for the
next couple of hours.

...Southern Plains into the Ozarks...

A thunderstorm complex ongoing southeast of Kansas City this evening
is located to the north of the synoptic front that stretches from
central MO through far southeast KS and northwest OK into the TX
Panhandle. Some cold pool organization is present per KEAX base
velocity data, with recent reports of wind damage and wind gusts up
to 59 mph. The air mass ahead of the storms has been slightly
modified by convective outflow but still remains sufficiently
buoyant to sustain the ongoing storms with a continued risk for
isolated severe wind gusts through the remainder of the evening.

Over the southern Plains, widely scattered thunderstorms continue
this evening along and in the immediate wake of the front. The air
mass ahead of the front remains hot with a deep, well-mixed boundary
layer, which will remain supportive of locally severe wind gusts for
the next hour or two.

..Mead.. 09/10/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 05:38:28 2026

ACUS01 KWNS 100538
SWODY1
SPC AC 100536

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1236 AM CDT Thu Sep 10 2026

Valid 101200Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE SOUTHERN MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast Thursday afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles Thursday afternoon and
evening.

...Synopsis...

A short-wave trough initially over the upper MS and mid MO Valleys
Thursday morning will continue east into the Great Lakes and OH
Valley with a preceding belt of enhanced mid-level flow extending
into the Mid-Atlantic. Elsewhere, a vorticity maximum (possible MCV)
is forecast to progress from western KS into the Ozark Plateau by
Thursday night. At the surface, a cool front is expected to advance
through the Mid-Atlantic during the forecast period with the western
extension of the boundary settling more slowly south through the OH
Valley, Ozark Plateau, and southern Plains. The location of the
surface front is likely to be modulated by clusters of thunderstorms
that are expected to be ongoing Thursday morning from portions of
the OH Valley into the southern Plains.

...Southern Plains to the southern Mid-Atlantic coast...

To the south of residual cloudiness and lingering showers and
thunderstorms, a hot air mass is expected to develop by afternoon
with temperatures well into the 90s to around 100 F over the
southern Plains into the lower MS Valley, and upper 80s to mid 90s
from the TN Valley to Mid-Atlantic. While mid-level lapse rates will
remain generally less than 7 C/km, the daytime heating coupled with
dewpoints in the 60s to low/mid 70s will yield a moderately unstable
air mass by afternoon with MLCAPE ranging from 1500-2500+ J/kg.

The 00Z models indicate a gradual increase in thunderstorm coverage
and intensity through the afternoon, aided by forcing for ascent
associated with the mid-level disturbances mentioned in the
synopsis, as well as convergence along the synoptic front and any
existing outflow boundaries. The strongest mid/upper-level wind
field and resultant vertical shear are expected to largely remain to
the north of the effective warm sector. However, 30-35 kt of
deep-layer shear is forecast along the front over portions of the OH
Valley into the southern Mid-Atlantic, where some storm organization
appears possible with the primary hazard being damaging wind gusts.
Vertical shear will diminish with southwestward extent from the TN
Valley into the OK-TX Red River Valley; however, the presence of a
relatively deep, well-mixed boundary layer will be supportive of
sporadic damaging winds with isolated severe gusts.

...Raton Mesa Vicinity...

Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. The given environment will be supportive of
multicell and supercell storm modes with an associated risk for
large hail.

..Mead/Chalmers.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 12:46:06 2026

ACUS01 KWNS 101245
SWODY1
SPC AC 101244

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0744 AM CDT Thu Sep 10 2026

Valid 101300Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..Mosier/Lyons.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 16:16:26 2026

ACUS01 KWNS 101616
SWODY1
SPC AC 101615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Sep 10 2026

Valid 101630Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 16:42:30 2026

ACUS01 KWNS 101642
SWODY1
SPC AC 101615

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
1115 AM CDT Thu Sep 10 2026

Valid 101630Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 19:41:18 2026

ACUS01 KWNS 101941
SWODY1
SPC AC 101940

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0240 PM CDT Thu Sep 10 2026

Valid 102000Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 10 19:54:58 2026

ACUS01 KWNS 101954
SWODY1
SPC AC 101940

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
Issued by 15th OWS Scott Air Force Base IL
0240 PM CDT Thu Sep 10 2026

Valid 102000Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO THE MID-ATLANTIC COAST...

...SUMMARY...
Sporadic damaging wind gusts appear possible from the southern
Plains to the southern Mid-Atlantic coast this afternoon and
evening. Isolated occurrences of large hail may occur over portions
of south-central Colorado into northeast New Mexico and perhaps
portions of the Oklahoma and Texas Panhandles this afternoon and
evening.

...Southern Plains to the southern Mid-Atlantic coast...
Recent surface analysis places the primary cold front from the St.
Lawrence Valley west-southwestward through Lower MI, northern IL,
and southern IA. The front then shifts more southwestward through
central KS through the central OK and northwest TX Panhandles into
far northeast NM. A broad area of showers and thunderstorms extends
from southwest KS and the eastern TX/OK Panhandles through the Lower
MO Valley and into the middle OH Valley. Much of this activity
precedes the cold front and is supported by either modest low-level
warm-air advection and/or convergence along
southward/southeastward-progressing outflows.

Strong heating is anticipated south of residual cloudiness and
lingering showers/thunderstorms, with temperatures well into the 90s
to around 100 F over the southern Plains into the lower MS Valley,
and upper 80s to mid 90s from the TN Valley to Mid-Atlantic. This
heating coupled with dewpoints in the 60s to low/mid 70s will yield
a moderately unstable air mass by afternoon with MLCAPE ranging from
1000 J/kg across the Mid-Atlantic vicinity to 2000-2500 J/kg across
the southern Plains. This increased buoyancy coupled with
convergence along the synoptic front (and any existing outflow
boundaries) and modest large-scale ascent should result in
thunderstorm activity persisting throughout the afternoon and
evening. Some increase in intensity is possible too, particularly
from north-central TX in the Mid-South vicinity where buoyancy will
be highest. The presence of a relatively deep, well-mixed boundary
layer will be supportive of sporadic damaging winds with isolated
severe gusts in these areas. Buoyancy will be more limited farther
east, but vertical shear will be stronger, and some more organized
bowing segments are possible. Damaging gusts will be the primary
severe risk over this region as well.

...Raton Mesa Vicinity...
Upslope flow of a moist boundary layer beneath mid-level lapse rates
of 7-8 C/km will yield moderate afternoon instability with MLCAPE of
1000-1500 J/kg. Isolated to widely scattered thunderstorm
development is anticipated by mid afternoon along the high terrain
amidst a vertically veering wind profile with up to 30-35 kt of
deep-layer shear. A few stronger storms are possible in this
environment, with isolated hail as the primary hazard. Increasing
low-level stability away from the terrain should keep the threat
relatively confined and short lived.

..15_ows.. 09/10/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 00:46:58 2026

ACUS01 KWNS 110046
SWODY1
SPC AC 110045

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Thu Sep 10 2026

Valid 110100Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE SOUTHERN
TEXAS PANHANDLE INTO THE SOUTH PLAINS OF TEXAS...

...SUMMARY...
The threat for widely scattered large hail and a few severe wind
gusts is expected to continue through the remainder of the evening
into tonight over the southern Texas Panhandle into the South Plains
of Texas. Isolated damaging wind gusts appear possible over the
Mid-South and vicinity tonight.

...Texas Panhandle into the South Plains of Texas...

A cluster of strong to severe thunderstorms, including supercells,
is ongoing this evening between Amarillo and Lubbock amidst a
moderately unstable air mass with MLCAPE up to 1500 J/kg and
effective bulk shear of 40-50 kt, per the 00Z Amarillo sounding.
Hail in excess of two inches was reported earlier this evening near
Amarillo with a more recent wind gust of 65 mph near Plainview.
There is some signal in water vapor imagery for a weak disturbance
moving into the northern TX Panhandle, which may aid in sustaining
the ongoing storms through 03-05Z with a continued risk for large
hail and a few severe wind gusts.

...Mid-South...

Surface analysis indicates a convectively modified front from
west-central AR into middle TN, with a pocket of locally stronger
instability (i.e., MLCAPE up to 2000-2500 J/kg) near and to the
north of the boundary, per latest mesoanalysis. Forcing associated
with a subtle mid-level disturbance moving through south-central MO
is contributing to a gradual increase in storm coverage this evening
over far southeast MO into northeast AR. Time-lagged HRRR and RRFS
ensemble data suggest that a further increase in storm coverage is
possible late this evening into tonight over northern AR and
southeast MO into portions of northwest TN and western KY. Regional
VWPs indicate 0-6 km shear up to 30-35 kt, which may be sufficient
to support episodic storm organization with an associated risk for
isolated damaging wind gusts.

..Mead.. 09/11/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 05:28:36 2026

ACUS01 KWNS 110528
SWODY1
SPC AC 110526

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 AM CDT Fri Sep 11 2026

Valid 111200Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE UPPER
MISSISSIPPI VALLEY INTO THE MID MISSOURI VALLEY...

...SUMMARY...
Scattered severe thunderstorms capable of large hail, potentially in
excess of two inches, a few tornadoes, and damaging wind gusts are
expected over portions of the upper Mississippi Valley Friday
afternoon into night. Storm development is more uncertain with
southward extent into the central Plains, where a conditional risk
for mainly large hail and severe wind gusts exists late Friday
afternoon through evening. Isolated occurrences of damaging wind
gusts appear possible from the Mid-South into the Carolinas and
Virginia.

...Synopsis...

A low-amplitude short-wave trough moving onto the Pacific Northwest
coast late this evening will progress through the northern Rockies
before reaching the ND/SK/MB border region by Friday evening.
Meanwhile, a preceding, lower-latitude disturbance is forecast to
move through SD into MN on Friday with strengthening mid/upper-level
winds and modest height falls accompanying these perturbations over
the northern Plains into the upper MS Valley. Elsewhere, a vorticity maximum/weak upper low will drift east from the Ozark Plateau into
the mid/lower MS Valley.

At the surface, an area of low pressure over western SD at 12Z
Friday is forecast to deepen slightly while developing into
northeast SD by afternoon, before subsequently weakening while
moving through central MN Friday night. The surface cyclone will
coincide with a cold front that will advance through the northern
Plains and the upper MS Valley. The trailing extension of the
boundary will move more slowly south into the mid MO Valley and
central High Plains. A dryline will precede the cold front with that
feature extending from eastern SD through central NE into western KS
by late afternoon. Elsewhere, a synoptic front modulated by
convective outflow is expected to stretch from the Mid-South into
the southern Mid-Atlantic on Friday afternoon.

...Upper Mississippi Valley into the mid Missouri Valley...

A low-level jet (LLJ) is forecast to strengthen through the day from
the mid MO Valley into the upper Midwest, enhancing the poleward
flux of an increasingly moist air mass ahead of the surface low and
attending frontal system. The moisture increase will occur beneath a
plume of steep mid-level lapse rates with MLCAPE increasing to
1500-2500+ J/kg by mid to late afternoon. Initial storm development
is expected at that time across portions of northern MN along or
ahead of the front, on the northern fringe of stronger capping.

Vertically veering wind profiles with 40-45 kt of deep-layer shear
will support supercells as the initial storm mode with the primary
hazard being large hail, some of which could exceed two inches. A
few tornadoes appear possible with any sustained supercells from
late afternoon into evening when the strengthening LLJ enhances
low-level shear with effective SRH increasing to 250-300 m2/s2.
Storms are expected to gradually grow upscale along the cold front
during the evening, at which point, the risk for damaging winds
should increase.

Severe weather potential becomes more conditional with southward
extent along the front and dryline in the mid MO Valley owing to
stronger capping and weaker height falls/forcing for ascent. The 00Z
models (convection-allowing and parameterized) indicate a relative
minimum in thunderstorm chances over eastern SD and southwest MN
with increasing probabilities from northeast NE into south-central
NE and north-central KS. Given surface-based storm initiation and
sustenance, CAPE-shear parameter space will favor supercells capable
of all hazards from eastern SD and southwest MN into northeast NE
and northwest IA, with generally a wind and hail threat farther
south along the NE-KS state line.

...Mid-South into the Carolinas and Virginia...

Areas of thunderstorms are expected to be ongoing at 12Z Friday from
the Ozark Plateau into the southern Mid-Atlantic. Stronger heating
on the southern fringe any lingering cloud cover will combine with boundary-layer dewpoints in the low to mid 70s F to yield MLCAPE of
1500-3000 J/kg by afternoon. Aided by forcing for ascent associated
with the mid-level trough approaching the mid/lower MS Valley,
thunderstorms are expected to increase in coverage and intensity
through the afternoon along and ahead of the composite surface
boundary. Weak vertical shear will limit storm organization with
mainly pulse storms expected. Nonetheless, the presence steep
low-level lapse rates and abundant moisture will be supportive of
wet microbursts capable of locally damaging wind gusts.

..Mead/Halbert.. 09/11/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 12:28:38 2026

ACUS01 KWNS 111228
SWODY1
SPC AC 111226

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0726 AM CDT Fri Sep 11 2026

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes should
occur late this afternoon into tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a conditional risk for large hail and
severe gusts will exist late this afternoon into the evening.

...Upper Midwest into the Central Plains...
Primary large-scale upper troughing will remain over central Canada
today, with an embedded mid-level shortwave trough forecast to eject
eastward over the northern Plains into the Upper Midwest through the
period. A modest surface response will occur across SD as the
shortwave trough ejects eastward, with most guidance suggesting a
sub-1000 mb low will develop into eastern SD by 12/00Z. A surface
cold front attendant to this low and the primary surface low over
central Canada will move east-southeastward across parts of the
Upper Midwest into the northern Plains, with a dryline extending
southward across the central Plains. A narrow corridor of 60s
surface dewpoints will be in place ahead of the cold front/dryline,
with diurnal heating aiding moderate destabilization along with
steepened mid-level lapse rates. Most guidance, including recent
NAM/RAP runs, show minimal MLCIN along/ahead of the front in far
northeast SD/western MN by 22-01Z. Convective development appears
likely in this time frame across this region, owing to sufficient
low-level convergence along the front coupled with forcing for
ascent associated with the mid-level shortwave trough.

Various NAM/RAP forecast soundings show strongly veering and
gradually strengthening winds with height through low/midlevels, and
35-45 kt of deep-layer shear will easily support organized
convection. Initial supercells should pose a threat for large hail
(isolated 2+ inches possible), but convective mode will probably
trend towards clustering fairly quickly given the presence of the
cold front and strengthening low-level jet this evening. Any
supercells that can remain at least semi-discrete into the early
evening may also have a tornado threat with greater low-level shear
forecast in this time frame. But, confidence in this scenario
occurring remains fairly low due to the mode transition expected.
Scattered severe/damaging winds should occur with any clusters or
bowing line segments that can develop and spread eastward through
the evening. However, the wind threat will likely wane with eastward
extent across MN into western WI by late this evening given the
narrow zone of destabilization forecast.

Convective initiation and overall thunderstorm coverage from
southeast SD/southwest MN into the central Plains are highly
uncertain and conditional this afternoon/evening, as the better
forcing for ascent with the shortwave trough will likely remain
across western/northern MN along and northeast of the surface low.
Still, a favorable thermodynamic environment and sufficient (25-35
kt) deep-layer shear would conditionally support severe hail/wind
with any thunderstorms that can develop and be sustained. There is
some signal in model guidance for successful convective initiation
across southern NE into northern KS late this afternoon/evening
where hotter surface temperatures are forecast. The southern extent
of the Marginal Risk has been adjusted to account for this
possibility, and the Slight Risk has generally been confined to
where greater confidence exists in robust thunderstorm development
(far northeast SD into western/northern MN).

...Mid-South into the Tennessee Valley/Carolinas and Virginia...
Two weak mid-level perturbations are evident in water vapor
satellite imagery this morning across the Southeast: one over AR,
and the other along the central Gulf Coast. These features will
generally track east-northeastward through the day, and should aid
additional thunderstorm development this afternoon. A stalled
surface front extending from the ArkLaTex into the TN Valley and
northeastward to VA should also provide a focus for thunderstorms.
Current expectations are for generally disorganized/pulse-type
convection to pose a threat for occasional damaging winds as diurnal
heating destabilizes the boundary layer and steepens low-level lapse
rates. But, modestly enhanced mid-level flow across parts of the
Mid-South and VA could promote loosely organized clusters with some
damaging wind threat as well.

..Gleason/Lyons.. 09/11/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 16:29:36 2026

ACUS01 KWNS 111629
SWODY1
SPC AC 111627

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1127 AM CDT Fri Sep 11 2026

Valid 111630Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes are
expected late this afternoon and tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a risk for large hail and severe
gusts may exist late this afternoon into the evening.

...Upper Midwest/central Plains...
An eastward-progressive belt of quasi-zonal westerlies exists over
the northern half of the CONUS, to the south of upper troughing over
the Canadian Prairies/central Canada, and the east of the amplifying
upper trough off the coastal Pacific Northwest. Weak frontal wave
development will occur from eastern South Dakota into Minnesota as a
cold front spreads eastward, with the front eventually overtaking a
pre-frontal trough/dryline across the central Plains.

A narrow corridor of 60s F surface dewpoints are in place ahead of
the cold front/dryline, with diurnal heating aiding moderate
destabilization along with steepened mid-level lapse rates. Minimal
MLCIN is expected along/ahead of the front in far northeast South Dakota/western Minnesota into/just after peaking heating. Convective development appears likely in this time frame across this region,
especially across Minnesota, owing to sufficient low-level
convergence along the front coupled with forcing for ascent
associated with the mid-level shortwave trough.

Strongly veering and gradually strengthening winds with height
through low/mid-levels, and 35-45 kt of deep-layer shear will easily
support organized convection. Initial supercells should pose a
threat for large hail (isolated 2+ inches possible), but convective
mode will probably trend towards clustering fairly quickly given the
presence of the cold front and strengthening low-level jet this
evening. Any supercells that can remain at least semi-discrete into
the early evening may also have a tornado threat with greater
low-level shear forecast in this time frame. Scattered
severe/damaging winds should occur with any clusters or bowing line
segments that can develop and spread eastward through the evening.
However, the wind threat will likely wane with eastward extent
across Minnesota into western Wisconsin by late this evening given
the narrow zone of destabilization forecast.

Farther southwest, convective initiation and overall thunderstorm
coverage from southeast South Dakota/southwest Minnesota
southwestward into Nebraska and northern Kansas are more uncertain
and probably more limited/conditional late this afternoon and
evening, as the better forcing for ascent with the shortwave trough
will remain regionally focused to the north. Still, a favorable
thermodynamic environment and sufficient (25-35 kt) deep-layer shear
would conditionally support severe hail/wind with any thunderstorms
that can develop and be sustained.

...Mid-South/Tennessee Valley/Carolinas and Virginia...
Multiple convectively augmented mid-level perturbations remain
evident at midday in satellite/radar imagery, including over the
Ozarks as well as the middle Gulf Coast in vicinity of southern
Alabama. A stalled surface front extending from the ArkLaTex
east-northeastward into the Tennessee Valley and Virginia will
provide a focus for thunderstorms. Generally speaking, expectations
are for generally disorganized/pulse-type convection to pose a
threat for occasional damaging winds as diurnal heating destabilizes
the boundary layer and steepens low-level lapse rates. However, a
modest enhancement to mid-level flow across parts of the Mid-South
(25 kt mid-levels per Little Rock AR WSR-88D VWP), as well as
Virginia, could promote a couple of loosely organized clusters with
a bit more of a focused damaging wind threat.

..Guyer/Weinman.. 09/11/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 11 20:02:50 2026

ACUS01 KWNS 112002
SWODY1
SPC AC 112000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Fri Sep 11 2026

Valid 112000Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
(some 2+ inches), damaging winds, and a couple of tornadoes are
expected late this afternoon and tonight across parts of the Upper
Midwest. Thunderstorm development is more uncertain farther south
into the central Plains, where a risk for large hail and severe
gusts may exist late this afternoon into the evening.

...20Z Update...
The ongoing forecast remains mostly on track with most areas
remaining unchanged. Given the signal for the cold front to push
into northern Kansas by early Saturday morning, along with at least
a modest low-level jet, marginal wind/hail probabilities have been
extended into more of central Kansas for the conditional potential
of severe storms overnight.

..Wendt.. 09/11/2026

.PREV DISCUSSION... /ISSUED 1127 AM CDT Fri Sep 11 2026/

...Upper Midwest/central Plains...
An eastward-progressive belt of quasi-zonal westerlies exists over
the northern half of the CONUS, to the south of upper troughing over
the Canadian Prairies/central Canada, and the east of the amplifying
upper trough off the coastal Pacific Northwest. Weak frontal wave
development will occur from eastern South Dakota into Minnesota as a
cold front spreads eastward, with the front eventually overtaking a
pre-frontal trough/dryline across the central Plains.

A narrow corridor of 60s F surface dewpoints are in place ahead of
the cold front/dryline, with diurnal heating aiding moderate
destabilization along with steepened mid-level lapse rates. Minimal
MLCIN is expected along/ahead of the front in far northeast South Dakota/western Minnesota into/just after peaking heating. Convective development appears likely in this time frame across this region,
especially across Minnesota, owing to sufficient low-level
convergence along the front coupled with forcing for ascent
associated with the mid-level shortwave trough.

Strongly veering and gradually strengthening winds with height
through low/mid-levels, and 35-45 kt of deep-layer shear will easily
support organized convection. Initial supercells should pose a
threat for large hail (isolated 2+ inches possible), but convective
mode will probably trend towards clustering fairly quickly given the
presence of the cold front and strengthening low-level jet this
evening. Any supercells that can remain at least semi-discrete into
the early evening may also have a tornado threat with greater
low-level shear forecast in this time frame. Scattered
severe/damaging winds should occur with any clusters or bowing line
segments that can develop and spread eastward through the evening.
However, the wind threat will likely wane with eastward extent
across Minnesota into western Wisconsin by late this evening given
the narrow zone of destabilization forecast.

Farther southwest, convective initiation and overall thunderstorm
coverage from southeast South Dakota/southwest Minnesota
southwestward into Nebraska and northern Kansas are more uncertain
and probably more limited/conditional late this afternoon and
evening, as the better forcing for ascent with the shortwave trough
will remain regionally focused to the north. Still, a favorable
thermodynamic environment and sufficient (25-35 kt) deep-layer shear
would conditionally support severe hail/wind with any thunderstorms
that can develop and be sustained.

...Mid-South/Tennessee Valley/Carolinas and Virginia...
Multiple convectively augmented mid-level perturbations remain
evident at midday in satellite/radar imagery, including over the
Ozarks as well as the middle Gulf Coast in vicinity of southern
Alabama. A stalled surface front extending from the ArkLaTex
east-northeastward into the Tennessee Valley and Virginia will
provide a focus for thunderstorms. Generally speaking, expectations
are for generally disorganized/pulse-type convection to pose a
threat for occasional damaging winds as diurnal heating destabilizes
the boundary layer and steepens low-level lapse rates. However, a
modest enhancement to mid-level flow across parts of the Mid-South
(25 kt mid-levels per Little Rock AR WSR-88D VWP), as well as
Virginia, could promote a couple of loosely organized clusters with
a bit more of a focused damaging wind threat.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 00:30:48 2026

ACUS01 KWNS 120030
SWODY1
SPC AC 120028

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0728 PM CDT Fri Sep 11 2026

Valid 120100Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER FAR EASTERN
SOUTH DAKOTA INTO PORTIONS OF MINNESOTA...

...SUMMARY...
Widely scattered severe thunderstorms capable of producing large
hail up to two inches, damaging winds, and a couple of tornadoes
will continue through the remainder of the evening into tonight from
far eastern South Dakota into portions of Minnesota. Isolated
occurrences of severe wind gusts and large hail remain possible over
parts of the central Plains tonight.

...Upper Mississippi Valley into the central Plains...

A broken band of thunderstorms has recently developed from far
eastern SD into north-central MN within a relatively narrow
instability axis preceding a surface cold front and dryline. The
presence of steep mid-level lapse rates (per 00Z ABR sounding) atop boundary-layer dewpoints in the mid to upper 60s F is resulting in
MLCAPE up to 1500-2000 J/kg. As mentioned above, the corridor of
stronger instability and minimal capping is rather narrow
longitudinally, which suggests the severe weather threat may remain
somewhat limited spatially into tonight.

The KFSD VWP is likely indicative of the ambient kinematic
environment, which features 35-40 kt of deep-layer shear and
relatively strong low-level shear, supportive of a supercell storm
mode with the primary hazard being large hail up to two inches.
Tornado potential will be conditional on the maintenance of
semi-discrete supercells residing within the narrow axis of minimal
convective inhibition. Damaging wind potential may tend to increase
by late evening as thunderstorms evolve into line segments.

Additional storms appear possible late this evening into tonight
ahead of a southeastward-moving cold front over portions of eastern
and central NE. Similar to locations to the north, a relatively
narrow zone of minimal convective inhibition and moderate
instability exists ahead of the front, which leads to uncertainty in
the areal coverage and duration of the threat. Severe wind gusts
will be the primary hazard with any surface-based storms that can
become established, though isolated occurrences of large hail are
also possible.

..Mead.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 05:26:28 2026

ACUS01 KWNS 120525
SWODY1
SPC AC 120524

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 AM CDT Sat Sep 12 2026

Valid 121200Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS...OZARK PLATEAU...AND UPPER OHIO
VALLEY...

...SUMMARY...
Widely scattered severe storms capable of large hail up to two
inches and damaging wind gusts appear possible over portions of the
central and southern Plains into the Ozark Plateau on Saturday into
Saturday night. Isolated occurrences of damaging wind gusts may also
occur over portions of the upper Ohio Valley Saturday afternoon.

...Synopsis...

A belt of enhanced mid/upper-level flow will persist over the
north-central U.S., downstream from a vigorous upper low moving into
the Pacific Northwest. Meanwhile, a lower-latitude trough over the
lower OH and lower MS Valleys Saturday morning is forecast to weaken
while progressing through the OH and TN Valleys. At the surface, a
cold front will advance through the upper Great Lakes with the
trailing extension of the boundary pushing south through the lower
MO Valley and central Plains before linking with a surface low over
the southern High Plains.

...Central and Southern Plains into the Ozark Plateau...

Persistent capping across the pre-frontal warm sector and generally
weak forcing for ascent lead to considerable uncertainty in
thunderstorm evolution through the forecast period. A number of the
00Z models (both convection-allowing and parameterized) indicate
areas of thunderstorms ongoing at 12Z Saturday over the central
Plains within a zone of modest warm advection and moisture transport
associated with a weakening low-level jet. One possible scenario is
for the continued southeast movement of the early-day storms through
eastern KS and southwest MO into portions of OK and AR by afternoon,
where a hot and moderate to strongly unstable air mass (i.e., MLCAPE
up to 2000-3000 J/kg) is forecast to develop. The instability
combined with around 30 kt of deep-layer shear would support
organized cold pool development in that scenario with an associated
risk for damaging wind gusts and large hail.

Renewed storm development appears possible from late morning into
afternoon from north of the front in south-central and southeast NE
to along or ahead of the front in northeast KS. Up to 40 kt of
deep-layer shear will coincide with the northern extension of the
stronger instability mentioned above to support supercell storm
modes with an associated risk for large hail up to two inches and
damaging wind gusts.

A separate thunderstorm regime may also evolve by mid to late
afternoon over the eastern OK and TX Panhandles into western OK in
the vicinity of the surface low and southward-sagging front.
Forecast soundings indicate a deep, well-mixed boundary layer, which
will be supportive of a few severe wind gusts and isolated large
hail.

Confidence in any of the above scenarios/regimes remains too low to
include Slight Risk wind and hail probabilities with this forecast.
A categorical upgrade is possible in subsequent Day 1 outlooks once
finer-scale details become more clear.

...Upper Ohio Valley...

A spatially narrow corridor of stronger heating and resultant
instability (MLCAPE up to 1500-2000 J/kg) is forecast to develop
during the afternoon between denser clouds and precipitation to the
west, and a backdoor front/stationary boundary to the east.
Thunderstorms are expected to increase in coverage and intensity
through the afternoon within the instability axis, aided by
increased forcing for ascent associated with the approaching
mid-level trough. While mid-level lapse rates are expected to remain
relatively weak, deep-layer shear increasing to 30-35 kt coupled
with steepening low-level lapse rates suggests the potential for
some storm organization with the primary hazard being damaging wind
gusts. Backed low-level winds in the vicinity of the surface front
will boost low-level shear slightly and a brief tornado cannot be
ruled out as mature storms approach the frontal zone from the west.

..Mead/Halbert.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 12:50:44 2026

ACUS01 KWNS 121250
SWODY1
SPC AC 121248

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Sat Sep 12 2026

Valid 121300Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL/SOUTHERN PLAINS...

...SUMMARY...
Isolated to scattered severe thunderstorms capable of producing
large to very large hail and severe/damaging winds may occur across
parts of the central/southern Plains into the Ozarks this afternoon
and evening.

...Central/Southern Plains into the Ozarks...
Mainly elevated thunderstorms have persisted overnight into the
early morning across southern NE into eastern KS/western MO, aided
by a modest low-level jet. This activity will probably tend to
weaken through the remainder of the morning, but some recent
guidance suggests additional thunderstorms developing along its
outflow across southern KS/northern OK over the next few hours. If
this development occurs, it would potentially complicate
destabilization and severe potential later today. Recent surface
observations also show a fairly strong cold front draped from
eastern CO into KS and northwest MO. This boundary will likely serve
as a focus for robust thunderstorm development this
afternoon/evening as well. With a rather moist low-level airmass
forecast to be present along/south of the front, current
expectations are for a narrow zone of moderate to strong instability
(MLCAPE 2000-3500 J/kg) to develop this afternoon from the eastern
OK/TX Panhandles into southern KS/northern OK. Weak low-level winds
will veer to west-northwesterly and strengthen some with height
through mid/upper levels, supporting around 30-40 kt of deep-layer
shear and updraft organization. While large-scale ascent will remain
fairly weak/nebulous across the southern/central Plains, most
guidance shows at least isolated robust thunderstorm development
along the front by 21-23Z as convective temperatures are reached.

While there is still uncertainty regarding convective evolution and
persistence of ongoing thunderstorms this morning, some signal
exists in most recent short-term guidance that isolated to scattered
convection will form along much of the length of the front later
today in a rather favorable environment to support severe
thunderstorms. Any sustained supercells would pose a threat for
large to very large hail, with steep mid-level lapse rates and ample instability in the hail-growth zone supporting potential for 2+ inch
diameter hail on an isolated basis. Somewhat higher-based convection
also appears probable from the eastern OK/TX Panhandles into parts
of southwest/south-central KS and northern OK, where a very
well-mixed boundary layer with steep low/mid-level lapse rates
should promote an environment that supports scattered severe
downdraft winds. Some gusts could exceed 75 mph. The potential for
clustering this afternoon and evening remains unclear, but some
chance for at least isolated severe/damaging winds may persist into
much of OK and the Ozarks, dependent on upstream convective
evolution in KS/western MO.

...Upper Ohio Valley...
A narrow corridor of filtered diurnal heating and related moderate
instability should develop across parts of the upper OH Valley this
afternoon between denser clouds and precipitation occurring across
OH, and a stationary boundary to the east. Thunderstorms will
gradually increase in coverage and intensity through the afternoon,
aided by forcing for ascent associated with an approaching weak
mid-level shortwave trough. While mid-level lapse rates will remain
poor, sufficient deep-layer shear coupled with modest steepening of
low-level lapse rates suggest some risk for occasional damaging
winds with any loosely organized clusters/line segments that can
form.

..Gleason/Lyons.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 16:37:14 2026

ACUS01 KWNS 121637
SWODY1
SPC AC 121635

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1135 AM CDT Sat Sep 12 2026

Valid 121630Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTH-CENTRAL PLAINS...

...SUMMARY...
Isolated to scattered severe thunderstorms capable of producing
large to very large hail and severe/damaging winds may occur across
parts of the south-central Plains into the Ozarks this afternoon and
evening.

...Central/Southern Plains to the Ozarks...
Scattered mainly elevated thunderstorms continue at midday across
the region, including the strongest/occasionally-severe storms
across southeast Nebraska into northeast Kansas that are occurring
near/just behind a southeastward-moving cold front. Some severe hail
will remain possible as these storms continue southeastward on the
edge of the primary instability reservoir.

This front, augmented by early day outflows, will otherwise serve as
a focus for more robust thunderstorm development this
afternoon/evening as well. With a rather moist low-level airmass
forecast to be present along/south of the front, current
expectations are for a narrow zone of moderate to strong instability
(MLCAPE 2000-3500 J/kg) to develop this afternoon from the eastern Oklahoma/Texas Panhandles across southern Kansas and northern
Oklahoma. Weak low-level winds will veer to west-northwesterly and
strengthen some with height through mid/upper levels, supporting
around 30-40 kt of deep-layer shear and updraft organization. While
large-scale ascent will remain fairly weak/nebulous across the
southern/central Plains, most guidance shows at least isolated
robust thunderstorm development along the front by 21-23Z as
convective temperatures are reached.

Any sustained supercells would pose a threat for large to very large
hail, with steep mid-level lapse rates and ample instability in the
hail-growth zone supporting potential for 2+ inch
diameter hail on an isolated basis. Somewhat higher-based convection
is expected from the eastern Oklahoma/Texas Panhandles into southwest/south-central Kansas and northern Oklahoma, where a very
well-mixed boundary layer with steep low/mid-level lapse rates
will promote an environment that supports severe-caliber downdraft
winds. Some gusts could exceed 75 mph. A degree of storm clustering
could occur into this evening.

...Upper Ohio Valley...
A regional pocket of relatively cloud-free skies at midday will
contribute to filtered diurnal heating and moderate instability
across the region. Thunderstorms will further increase in coverage
and intensity through the afternoon, aided by forcing for ascent
associated with an approaching weak mid-level shortwave trough.
While mid-level lapse rates will remain poor, sufficient deep-layer
shear coupled with modest steepening of low-level lapse rates
suggest some risk for occasional damaging winds with any loosely
organized clusters/line segments that develop.

..Guyer/Wendt.. 09/12/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 12 20:02:54 2026

ACUS01 KWNS 122002
SWODY1
SPC AC 122000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sat Sep 12 2026

Valid 122000Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTH-CENTRAL PLAINS...

...SUMMARY...
Isolated to scattered severe thunderstorms capable of producing
large to very large hail and severe/damaging winds may occur across
parts of the south-central Plains into the Ozarks this afternoon and
evening.

...20Z Update...
The SLGT Risk in the central/southern Plains was expanded
southwestward across parts of western OK. Here, visible satellite
imagery shows increasingly agitated boundary-layer cumulus and
isolated convective initiation along the western portion of a
remnant outflow boundary. Temperatures in the 102-104F range
along/south of the wind shift will support scattered severe wind
gusts with any clusters that evolve. Additionally, the 15-percent
hail probabilities were expanded westward into parts of southwest KS
and northwest OK. Given steep midlevel lapse rates accompanying an
EML (sampled by the 18Z DDC sounding), initial semi-discrete
supercells should pose a risk of scattered severe hail before
clustering occurs. Elsewhere, the previous forecast remains on track
and minimal changes were needed.

..Weinman.. 09/12/2026

.PREV DISCUSSION... /ISSUED 1135 AM CDT Sat Sep 12 2026/

...Central/Southern Plains to the Ozarks...
Scattered mainly elevated thunderstorms continue at midday across
the region, including the strongest/occasionally-severe storms
across southeast Nebraska into northeast Kansas that are occurring
near/just behind a southeastward-moving cold front. Some severe hail
will remain possible as these storms continue southeastward on the
edge of the primary instability reservoir.

This front, augmented by early day outflows, will otherwise serve as
a focus for more robust thunderstorm development this
afternoon/evening as well. With a rather moist low-level airmass
forecast to be present along/south of the front, current
expectations are for a narrow zone of moderate to strong instability
(MLCAPE 2000-3500 J/kg) to develop this afternoon from the eastern Oklahoma/Texas Panhandles across southern Kansas and northern
Oklahoma. Weak low-level winds will veer to west-northwesterly and
strengthen some with height through mid/upper levels, supporting
around 30-40 kt of deep-layer shear and updraft organization. While
large-scale ascent will remain fairly weak/nebulous across the
southern/central Plains, most guidance shows at least isolated
robust thunderstorm development along the front by 21-23Z as
convective temperatures are reached.

Any sustained supercells would pose a threat for large to very large
hail, with steep mid-level lapse rates and ample instability in the
hail-growth zone supporting potential for 2+ inch
diameter hail on an isolated basis. Somewhat higher-based convection
is expected from the eastern Oklahoma/Texas Panhandles into southwest/south-central Kansas and northern Oklahoma, where a very
well-mixed boundary layer with steep low/mid-level lapse rates
will promote an environment that supports severe-caliber downdraft
winds. Some gusts could exceed 75 mph. A degree of storm clustering
could occur into this evening.

...Upper Ohio Valley...
A regional pocket of relatively cloud-free skies at midday will
contribute to filtered diurnal heating and moderate instability
across the region. Thunderstorms will further increase in coverage
and intensity through the afternoon, aided by forcing for ascent
associated with an approaching weak mid-level shortwave trough.
While mid-level lapse rates will remain poor, sufficient deep-layer
shear coupled with modest steepening of low-level lapse rates
suggest some risk for occasional damaging winds with any loosely
organized clusters/line segments that develop.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 13 00:47:50 2026

ACUS01 KWNS 130047
SWODY1
SPC AC 130045

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Sat Sep 12 2026

Valid 130100Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTH-CENTRAL PLAINS...

...SUMMARY...
Strong to severe storms capable of severe wind gusts and isolated
hail remain possible tonight across parts of the south-central
Plains.

...South-central Plains and vicinity...
Isolated strong to severe storms are ongoing this evening from
southwest KS into northwest OK and the TX Panhandle, with another
persistent storm cluster across eastern KS. Earlier storm
development across central/northwest OK was driven by very strong
heating in the vicinity of an outflow boundary, within a regime of
generally weak deep-layer flow/shear. This activity is expected to
generally weaken through late evening, due to the onset of nocturnal cooling/stabilization. However, isolated hail and strong to severe
gusts will remain possible with any remaining storms through
mid/late evening.

Another surface boundary is located across southern KS, with moist
low-level easterly flow in place between this boundary and the
outflow boundary across OK. Short-term CAM guidance continues to
depict persistence of strong to locally severe storms through late
evening within this regime from southern KS into far northern OK and
perhaps southwest MO, potentially aided by a modest strengthening of
the nocturnal low-level jet. While this convection may tend to
become increasingly elevated with time, favorable lapse rates and
buoyancy and sufficient deep-layer shear (as depicted on the 00Z DDC
sounding) will support vigorous cells and perhaps a loosely
organized cluster, with potential for strong to severe gusts and
isolated hail.

See MCDs 2290 and 2291 for more information regarding the short-term
threats in this region.

..Dean.. 09/13/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 13 06:00:34 2026

ACUS01 KWNS 130600
SWODY1
SPC AC 130558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Sun Sep 13 2026

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
OHIO VALLEY INTO THE NORTHEAST...AND ALSO ACROSS PARTS OF THE
CENTRAL/NORTHERN HIGH PLAINS...

...SUMMARY...
Strong to locally severe storms are possible across parts of upper
Ohio Valley and Northeast this afternoon and evening. Isolated
strong to severe storms are also possible across parts of the
central and northern High Plains.

...Parts of the Ohio Valley to the Northeast...
A mid/upper-level trough is forecast to amplify as it moves across
the Great Lakes region toward the Northeast through tonight. A
surface low will move across Quebec, as a trailing cold front moves
through the eastern Great Lakes and Northeast this afternoon and
evening. The strongest deep-layer flow and large-scale ascent will
tend to lag the cold front, but some strengthening of flow in the
700-500 mb layer is expected across the warm sector this afternoon,
resulting in favorable wind profiles for organized convection.

Moderate buoyancy is expected to develop by late afternoon as CINH
weakens, and widely scattered storm development is eventually
expected along/ahead of the front. Despite the favorable wind
profiles, weak midlevel lapse rates and modest ascent may tend to
limit updraft intensity. Guidance continues to vary regarding the
magnitude of severe potential, with the 00Z HRRR/RRFS more
aggressive in developing organized convection (and possible
supercells), while other HREF guidance depicts generally weak
convection.

Localized damaging wind and isolated hail may accompany the
strongest storms. If later observational and guidance trends support
the more aggressive scenario, then greater severe probabilities may
eventually be needed.

...Central/northern High Plains...
A mid/upper-level low/trough initially over the Pacific Northwest
will move toward the northern Rockies and High Plains through the
period. Diurnal destabilization will generally be limited ahead of
this trough, though a narrow zone of moderate buoyancy may develop
by late afternoon from northeast CO into southeast WY and the NE
Panhandle. Isolated storm development will be possible, with
sufficient deep-layer shear for at least transient storm
organization and isolated severe hail/wind potential.

While any diurnal storms may tend to weaken through the evening,
elevated convection is expected to increase in coverage across
western/central SD tonight. Moderate elevated buoyancy and
sufficient effective shear could support an isolated severe threat
with the initial elevated storm development across western SD,
though storm interference and weakening buoyancy may tend to limit
the longevity and eastward extent of the threat.

...Parts of MT into northwest ND...
Increasing ascent associated with the approaching mid/upper-level
low/trough will result in elevated storm development this evening
across MT, which will spread into northwest ND overnight. Generally
weak buoyancy is currently expected to limit organized severe
potential, though small hail and locally gusty winds could accompany
the strongest storms.

..Dean/Halbert.. 09/13/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 13 12:46:18 2026

ACUS01 KWNS 131246
SWODY1
SPC AC 131244

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0744 AM CDT Sun Sep 13 2026

Valid 131300Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY INTO THE NORTHEAST...AND THE CENTRAL/NORTHERN HIGH
PLAINS...

...SUMMARY...
Strong to locally severe thunderstorms will be possible across parts
of the upper Ohio Valley into the Northeast this afternoon and
evening. Isolated strong to severe thunderstorms may also occur
across parts of the central and northern High Plains.

...Ohio Valley into the Northeast...
Within large-scale upper troughing over eastern Canada, a strong west-southwesterly mid-level jet will overspread the Great Lakes
into the OH Valley and Northeast by this evening. A surface cold
front will likewise track eastward across these regions through the
period. While a seasonably moist low-level airmass will be in place
ahead of the cold front, poor lapse rates aloft (around 6-6.5 C/km)
and cloud cover should limit the degree of destabilization that can
occur this afternoon. Still, even with the thermodynamic environment
remaining marginal, strengthening mid-level flow through the day
will support 35-45 kt of deep-layer shear and the potential for
organized convection.

Current expectations are for isolated to scattered thunderstorms to
develop along/ahead of the front by mid afternoon (around 19-22Z)
from parts of OH into western NY, and then spread quickly eastward
across the upper OH Valley into the Northeast. The deep-layer shear
will be strong enough for supercells initially, with perhaps a marginal/isolated hail threat even with the poor lapse rates present
aloft. But, clusters/bowing segments with an isolated damaging wind
threat should quickly develop given the linear forcing of the front.
This convection is forecast to weaken with eastward extent this
evening with the onset of nocturnal cooling, and as it encounters a
less unstable airmass. Confidence in a corridor of greater damaging
wind potential remains too low for higher severe wind probabilities
at this time.

...Central/Northern High Plains into the Mid Missouri Valley...
A closed mid/upper-level low over the Pacific Northwest this morning
will move eastward to the northern Rockies/High Plains through the
period. Diurnal destabilization will generally be limited ahead of
this low, though a narrow zone of weak instability may develop by
late afternoon from northeast CO into southeast WY and the NE
Panhandle in a modest low-level upslope flow regime. Isolated
thunderstorm development appears possible across this area, with
sufficient deep-layer shear for transient updraft organization and
isolated severe hail/wind potential.

While any diurnally developing convection will likely weaken through
the evening with the loss of daytime heating, elevated thunderstorms
should increase in coverage across western/central SD towards the
mid MO Valley late tonight into early Monday morning. Moderate
MUCAPE and sufficient cloud-layer shear could support an isolated
hail threat with the initial development across western SD, though mergers/interactions and weakening buoyancy will likely limit the
longevity and eastward extent of this threat into the mid MO Valley.

...Long Island/Southern New England...
Bands of precipitation with embedded thunderstorms are ongoing this
morning across NJ into southern NY/New England. This activity is
being aided by ascent associated with a low-amplitude mid-level
shortwave trough. As this feature develops northeastward through the
early afternoon, continued low-level warm/moist advection will occur
across Long Island into southern New England. Most guidance
continues to show minimal surface-based instability over land, with
generally elevated thunderstorms expected. Still, given the modestly
enhanced low-level flow/shear forecast, trends will be monitored for
signs of surface-based instability/thunderstorm potential.

..Gleason/Lyons.. 09/13/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 13 16:42:02 2026

ACUS01 KWNS 131641
SWODY1
SPC AC 131639

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1139 AM CDT Sun Sep 13 2026

Valid 131630Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHEAST...

...SUMMARY...
Isolated to widely scattered severe thunderstorms will be possible
across parts of the upper Ohio Valley into the Northeast this
afternoon and evening. Isolated strong to severe thunderstorms may
also occur across parts of the central and northern High Plains.

...Northeast and upper/middle Ohio Valley...
Have upgraded portions of the region to a categorical Slight Risk
with expectations of a semi-focused regional corridor of wind damage
later this afternoon through early evening. Within large-scale upper
troughing over eastern Canada, a strong west-southwesterly mid-level
jet will overspread the Great Lakes into the Ohio Valley and
Northeast later today into tonight. A surface cold front will
likewise track eastward across these regions through tonight. A
seasonably moist low-level airmass will be in place ahead of the
cold front, but poor lapse rates aloft (around 6-6.5 C/km) and cloud
cover should limit the degree of destabilization that can occur this
afternoon, although cloud cover has tended to thin/abate since early
this morning across the upper Ohio Valley. While the main influence
of the upstream upper-level trough will not arrive until this
evening, strengthening mid-level flow through the day will support
35-45 kt of deep-layer shear and the potential for organized bands
of convection.

At least widely scattered thunderstorms are expected to develop
along/ahead of the front by mid afternoon (around 19-22Z) from parts
of Ohio into western New York, and then spread quickly eastward
across the upper Ohio Valley into the Northeast. The deep-layer
shear will be strong enough for some supercells initially, with
perhaps a marginal/isolated hail threat even with the poor lapse
rates present aloft. But, clusters/bowing segments with an isolated
damaging wind threat should quickly develop given the linear forcing
of the front. This convection is forecast to weaken with eastward
extent this evening with the onset of nocturnal cooling, and as it
encounters a less unstable airmass.

...Wyoming and central/northern High Plains to Missouri Valley...
A closed mid/upper-level low over the Pacific Northwest this morning
will move eastward to the northern Rockies/High Plains through the
period. Diurnal destabilization will generally be limited ahead of
this low, though a narrow zone of weak instability may develop by
late afternoon across southern Wyoming, and across northeast
Colorado into the Nebraska Panhandle in a modest low-level upslope
flow regime. Isolated thunderstorm development is expected with
sufficient wind profiles for isolated severe hail/wind potential.

Elevated thunderstorms should again increase in coverage across
western/central South Dakota towards the mid Missouri Valley late
tonight into early Monday morning. Moderate MUCAPE and sufficient
cloud-layer shear could support an isolated hail threat with the
initial development across western/southern South Dakota, though mergers/interactions and weakening buoyancy will likely limit the
longevity and eastward extent of this threat into the mid Missouri
Valley.

..Guyer/Weinman.. 09/13/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Sep 13 19:58:50 2026

ACUS01 KWNS 131958
SWODY1
SPC AC 131957

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Sun Sep 13 2026

Valid 132000Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
OHIO VALLEY INTO CENTRAL NEW YORK...

...SUMMARY...
Isolated to widely scattered severe thunderstorms will be possible
across parts of the upper Ohio Valley into the Northeast this
afternoon and evening. Isolated strong to severe thunderstorms may
also occur across parts of the central and northern High Plains.

...20Z Update...
Minor changes where made to the ongoing forecast based on recent
observations and model guidance. The overall forecast reasoning
remains valid, however. See the previous discussion for additional
details.

..Wendt.. 09/13/2026

.PREV DISCUSSION... /ISSUED 1139 AM CDT Sun Sep 13 2026/

...Northeast and upper/middle Ohio Valley...
Have upgraded portions of the region to a categorical Slight Risk
with expectations of a semi-focused regional corridor of wind damage
later this afternoon through early evening. Within large-scale upper
troughing over eastern Canada, a strong west-southwesterly mid-level
jet will overspread the Great Lakes into the Ohio Valley and
Northeast later today into tonight. A surface cold front will
likewise track eastward across these regions through tonight. A
seasonably moist low-level airmass will be in place ahead of the
cold front, but poor lapse rates aloft (around 6-6.5 C/km) and cloud
cover should limit the degree of destabilization that can occur this
afternoon, although cloud cover has tended to thin/abate since early
this morning across the upper Ohio Valley. While the main influence
of the upstream upper-level trough will not arrive until this
evening, strengthening mid-level flow through the day will support
35-45 kt of deep-layer shear and the potential for organized bands
of convection.

At least widely scattered thunderstorms are expected to develop
along/ahead of the front by mid afternoon (around 19-22Z) from parts
of Ohio into western New York, and then spread quickly eastward
across the upper Ohio Valley into the Northeast. The deep-layer
shear will be strong enough for some supercells initially, with
perhaps a marginal/isolated hail threat even with the poor lapse
rates present aloft. But, clusters/bowing segments with an isolated
damaging wind threat should quickly develop given the linear forcing
of the front. This convection is forecast to weaken with eastward
extent this evening with the onset of nocturnal cooling, and as it
encounters a less unstable airmass.

...Wyoming and central/northern High Plains to Missouri Valley...
A closed mid/upper-level low over the Pacific Northwest this morning
will move eastward to the northern Rockies/High Plains through the
period. Diurnal destabilization will generally be limited ahead of
this low, though a narrow zone of weak instability may develop by
late afternoon across southern Wyoming, and across northeast
Colorado into the Nebraska Panhandle in a modest low-level upslope
flow regime. Isolated thunderstorm development is expected with
sufficient wind profiles for isolated severe hail/wind potential.

Elevated thunderstorms should again increase in coverage across
western/central South Dakota towards the mid Missouri Valley late
tonight into early Monday morning. Moderate MUCAPE and sufficient
cloud-layer shear could support an isolated hail threat with the
initial development across western/southern South Dakota, though mergers/interactions and weakening buoyancy will likely limit the
longevity and eastward extent of this threat into the mid Missouri
Valley.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 14 01:01:24 2026

ACUS01 KWNS 140101
SWODY1
SPC AC 140059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Sun Sep 13 2026

Valid 140100Z - 141200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The organized-severe threat appears low for the remainder of
tonight, though occasional strong storms will be possible this
evening across the central and northern High Plains, and overnight
into parts of the mid Missouri Valley.

...Parts of the Ohio Valley and Northeast...
A broken band of thunderstorms is ongoing this evening from parts of
the Upper Ohio Valley into the Northeast. Despite the presence of
moderate deep-layer flow/shear, longevity of organized storms within
this corridor has been limited by poor midlevel lapse rates and
generally modest buoyancy. Sporadic damaging winds have been
reported with the strongest of these storms, but a general weakening
trend is expected to continue through the evening. Localized wind
damage cannot be ruled out with any remaining vigorous storms,
though longevity of the remaining threat appears too limited to
maintain severe probabilities.

...Central/northern Plains into the Mid Missouri Valley...
Isolated strong storms are ongoing near the NE/WY/SD border region
this evening. While deep-layer shear and midlevel lapse rates are
favorable, generally modest low-level moisture and buoyancy have
limited the severe threat thus far. The time window for any
remaining diurnal convection to intensify appears limited, though
isolated hail cannot be entirely ruled out into late evening.

Late this evening, elevated convection is expected to increase in
coverage across the northern High Plains, and also in a separate
band into parts of the mid Missouri Valley. Relatively favorable
lapse rates and buoyancy may allow this convection to briefly
approach severe limits, but generally modest deep-layer shear and a
tendency for storm interference may tend to limit the
organized-severe threat. Confidence in more than brief elevated hail
potential is too low to include probabilities.

...Parts of central MT...
Isolated small but relatively organized cells have recently
developed to the east and south of Great Falls, in advance of a
mid/upper-level low/trough approaching the northern Rockies. While
favorable shear will continue to support occasional storm
organization, very weak buoyancy is expected to limit organized
severe potential through the evening. Small hail and localized
strong gusts may occur with the strongest storms.

..Dean.. 09/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 14 05:44:52 2026

ACUS01 KWNS 140544
SWODY1
SPC AC 140542

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 AM CDT Mon Sep 14 2026

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NE
AND WESTERN IA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of eastern Nebraska into western Iowa late this afternoon and
evening.

...Eastern NE/western IA...
A strong mid/upper-level trough will move eastward from the northern
Plains into the Upper Great Lakes through tonight. A deepening
surface low will move across the Canadian Prairies, while a
secondary low may develop along a trailing cold front/surface trough
across the central High Plains. This system will be accompanied by strengthening deep-layer flow from the central Plains into the Upper
Midwest.

Extensive elevated convection will likely be ongoing at the start of
the period from the mid Missouri Valley northward into the Dakotas
and western MN. In the wake of this early-day convection, rich
low-level moisture (with dewpoints in the 70s F) is forecast to
stream northward into eastern NE and western IA. This moistening
combined with relatively steep midlevel lapse rates will support
moderate to strong destabilization by late afternoon, while
low-level and deep-layer shear will become increasingly favorable
with time. The resulting environment will become conditionally
favorable for supercells capable of all severe hazards.

The strongest large-scale ascent will become focused north of the
region by afternoon, and it remains uncertain if heating in the wake
of morning convection will be sufficient to remove CINH within the
most favorable environment. If a supercell can become established
and move through this environment during the late afternoon/early
evening, then large to very large hail, localized damaging gusts,
and tornadoes will all be possible. While most guidance depicts
storm development by early evening, 00Z CAM guidance continues to
vary regarding the potential for sustained supercells, with
relatively quick clustering possible. Even in the absence of
sustained supercell development, the environment will be favorable
for severe hail and damaging wind with any persistent clusters into
the evening.

...Western/north-central KS...
Strong heating is expected near/south of a surface trough across
parts of western/central KS this afternoon. Scattered storm
development is expected by late afternoon from western into
north-central KS. Deep-layer shear will be weaker with southwest
extent, but steep low-level lapse rates and 25-35 kt of flow in the
850-500 mb layer will support potential for one or more loosely
organized clusters with at least localized severe-wind potential.

...Four Corners region into AZ...
Scattered storm development is expected later today from western CO
and southeast UT into parts of AZ/NM, within an anomalously moist
environment. The strongest mid/upper-level flow and deep-layer shear
within this region is expected over parts of UT/CO, though it is
uncertain if diurnal heating/destabilization will be sufficient for
an organized severe threat in this area. Some threat for strong
gusts and small to near-severe hail could evolve with the strongest
storms.

Farther south, flow will be weaker across AZ, resulting in generally disorganized storms. Localized strong gusts will be possible,
especially in areas where stronger pre-storm heating occurs during
the afternoon.

...Coastal NC...
A cold front will move southward across NC through the day today.
Large-scale ascent will generally be weak, though isolated storm
development will be possible as the front encounters richer moisture
and any sea breeze boundaries near the coast. Deep-layer shear
within a northwesterly flow regime will be sufficient for organized
convection, but poor midlevel lapse rates may limit updraft
intensity and potential for an organized severe threat. Any
sustained storms within this regime could produce locally gusty
winds and small hail.

..Dean/Halbert.. 09/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 14 12:48:32 2026

ACUS01 KWNS 141248
SWODY1
SPC AC 141246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Mon Sep 14 2026

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN NEBRASKA INTO WESTERN/CENTRAL IOWA...

...SUMMARY...
Scattered strong to severe thunderstorms should occur across parts
of eastern Nebraska into western/central Iowa this afternoon and
evening. Large hail, severe gusts, and a few tornadoes all appear
possible.

...Central Plains into Iowa...
A seasonably strong mid-level shortwave trough with 50-70+ kt
mid-level jet will advance quickly east-northeastward across the
northern Plains and south-central Canada today. Mid/upper-level
ridging will remain prominent over much of the Southeast and OH
Valley. Between these two features, a belt of around 30-50 kt
mid-level west-southwesterlies will persist across the central
Plains into the lower/mid MO Valley. The primary surface low over
the northern Plains this morning will develop into southern Saskatchewan/Manitoba by this evening, with a secondary surface low
likely to form along/near the NE/SD border by late afternoon.
Greater low-level moisture across KS will attempt to lift northward
along a warm front today across the central Plains ahead of a cold
front that will sweep southeastward across the northern/central
Plains through the period.

Ongoing convection this morning across the central Plains/mid MO
Valley is being aided by warm/moist advection associated with a
strong south-southwesterly low-level jet. This activity should tend
to remain elevated and sub-severe as it tracks quickly
east-northeastward through the late morning before eventually
weakening. In its wake, destabilization is forecast to rapidly occur
across eastern NE/western IA as rich low-level moisture quickly
streams northward. There is still some variability in short-term
guidance with the degree and northward extent of low-level moisture
return through late afternoon across this region, which introduces a
fair amount of uncertainty regarding how unstable the warm sector
will become. Even so, a narrow corridor of moderate to strong
instability (MLCAPE 2000-3000+ J/kg) appears plausible across
eastern NE/western IA and vicinity by 21-00Z, assuming surface
temperatures can warm into at least the low to mid 80s.

Robust thunderstorms should develop along or just ahead of the cold
front by late afternoon/early evening across eastern NE, with strengthening/favorable deep-layer shear for supercells initially.
Large hail may occur, but modest lapse rates aloft and a quick mode
transition to mainly clusters/line segments will probably limit the spatial/temporal extent of the hail threat. Nearly all guidance
continues to show a favorable environment for tornadoes across
eastern NE/western IA as the supercells/clusters spread quickly
eastward this evening, with a 40-50 kt low-level jet aiding the
development of ample effective SRH. But, various RAP forecast
soundings across this region show lingering low-level inhibition,
and it remains unclear whether convection will be able to fully take
advantage of the strong low-level shear. Even with this uncertainty,
a sustained surface-based supercell in this environment would
conditionally be capable of producing a strong tornado.

Otherwise, severe/damaging winds should become an increasing concern
as clusters develop and spread east-northeastward. Weak instability
with eastward extent in eastern IA and vicinity should limit the
severe risk tonight. While deep-layer shear will be somewhat weaker
with southward extent across the central Plains, at least isolated
severe gusts may also occur with high-based/loosely organized
convection that develops this afternoon from eastern CO into
western/northern KS along a surface trough. Confidence remains too
low in a more focused corridor of severe wind potential across this
region to include greater probabilities with this update.

...Northern Plains...
A band of elevated thunderstorms is occurring this morning across
the Dakotas as large-scale ascent preceding the shortwave trough
overspreads the northern Plains in tandem with strong low-level warm
advection. Latest surface observations and recent RAP forecast
soundings across this region show cool and stable conditions in the
boundary layer, which limits confidence in an isolated severe wind
threat this morning as convection moves quickly northeastward.
Still, small hail and gusty winds may occur given the enhanced background/gradient wind field and sufficient MUCAPE present, with
some convective enhancement possible.

...Southwest/Four Corners...
Scattered thunderstorm development will occur later today from
western CO and southeast UT into parts of AZ/NM as a fairly moist
low-level airmass gradually destabilizes. Modestly enhanced
mid-level westerly flow should be present this afternoon over parts
of UT/CO, though it is uncertain if diurnal heating and related
instability will be sufficient for an organized severe risk. Still,
isolated gusty winds and small to perhaps near-severe hail could
occur with the strongest thunderstorms. Farther south, flow will be
weaker across AZ, resulting in mostly disorganized convection. Even
so, localized strong gusts appear possible, especially where
stronger heating occurs and steeper low-level lapse rates develop
during the afternoon. Overall, confidence in an organized severe
risk is too low to include 5% hail/wind probabilities at this time.

...Eastern North Carolina...
A cold front will move southward across NC today. Large-scale ascent
will generally be weak, though isolated convective development may
occur as the front encounters greater low-level moisture and sea
breeze boundaries over coastal/eastern NC. Deep-layer shear within a northwesterly mid-level flow regime will be sufficient for organized thunderstorms, but poor mid-level lapse rates should tend to limit
updraft intensity and the overall severe threat. Regardless, any
thunderstorms that can develop and be sustained in this regime could
produce locally gusty winds and small hail.

..Gleason/Lyons.. 09/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 14 16:48:12 2026

ACUS01 KWNS 141647
SWODY1
SPC AC 141645

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1145 AM CDT Mon Sep 14 2026

Valid 141630Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
KANSAS AND SOUTHERN/EASTERN NEBRASKA INTO WESTERN/CENTRAL IOWA...

...SUMMARY...
Scattered strong to severe thunderstorms should occur across parts
of eastern Nebraska into western/central Iowa this afternoon and
evening. Large hail, severe wind gusts, and tornadoes all appear
possible. Severe thunderstorm winds will also be possible across northern/western Kansas.

...Central Plains to Iowa...
Well to the northeast of a warm front, semi-extensive elevated
convection continues at midday across Iowa and the eastern Dakotas
into western/southern Minnesota, although there has been a
diminishing trend, and cloud cover otherwise remains semi-prevalent
across Nebraska and western/northern Kansas.

A key forecast uncertainty remains the spatial location of primary
late-day surface-based destabilization and uncertain likelihood of
deep convective development toward/just after peak heating. The
semi-persistent convection, residual cloud cover, and
autumnal-approaching sun angle (and ramifications for air mass
recovery) may be factors for confining the most-favorable environment/surface-based potential to eastern Nebraska and western
Iowa.

This will be as a seasonably strong mid-level shortwave trough and
50-70+ kt mid-level jet spread quickly east-northeastward across the
northern Plains and Canadian Prairies today. While the primary
surface low will likely persist across western Kansas, a secondary
surface wave may materialize across east-central/northeast Nebraska.
Greater low-level moisture across Kansas and the lower Missouri
Valley quickly spread north-northeastward in tandem with a warm
front, although its exact late-day disposition/placement is a bit
uncertain. This will precede a cold front that will sweep
southeastward across the northern/central Plains through tonight. A
narrow corridor of moderate to strong instability (MLCAPE 2000-3000+
J/kg) still appears plausible across eastern Nebraska and western
Iowa into the 21-00Z time frame, coincident and roughly dependent
upon surface temperatures warming into at least the low to mid 80s
F.

Robust thunderstorms should develop along or just ahead of the cold
front by late afternoon/early evening across eastern Nebraska, with strengthening/favorable deep-layer shear for supercells initially.
Large hail may occur, but modest lapse rates aloft and a quick mode
transition to mainly clusters/line segments will probably limit the spatial/temporal extent of the hail threat. Most guidance continues
to show a favorable conditional environment for tornadoes across
eastern Nebraska/western Iowa as the supercells/clusters spread
quickly eastward this evening, with a 40-50 kt low-level jet aiding
the development of ample effective SRH. But, various RAP forecast
soundings across this region show lingering low-level inhibition,
and it remains unclear whether convection will be able to fully take
advantage of the strong low-level shear. Even with this uncertainty,
a sustained surface-based supercell in this environment would
conditionally be capable of producing a strong tornado.

Otherwise, severe/damaging winds should become an increasing concern
as clusters develop and spread east-northeastward this evening, with
other late-day high-based development also expected in vicinity of a pre-frontal boundary across southern Nebraska and northern/western
Kansas. Regarding the eastern Nebraska/western Iowa regime, weak
instability with eastward extent in eastern Iowa and vicinity should
limit the severe risk deeper into the night. While deep-layer shear
will be somewhat weaker with southward extent across the central
Plains, at least isolated severe wind gusts may also occur with high-based/loosely organized convection that develops this afternoon
from eastern Colorado into western/northern Kansas along a surface
trough.

...Southwest/Four Corners...
Scattered thunderstorm development will occur later today from
western Colorado and southeast Utah into parts of Arizona/New Mexico
as a fairly moist low-level airmass gradually destabilizes. Modestly
enhanced mid-level westerly flow should be present this afternoon
over parts of Utah/Colorado, though it is uncertain if diurnal
heating and related instability will be sufficient for an organized
severe risk. Still, isolated gusty winds and small to perhaps
near-severe hail could occur with the strongest thunderstorms.
Farther south, flow will be weaker across Arizona, resulting in
mostly disorganized convection. Even so, localized strong gusts
appear possible, especially where stronger heating occurs and
steeper low-level lapse rates develop during the afternoon. Overall,
confidence in an organized severe risk is too low to include 5%
hail/wind probabilities.

...Eastern North Carolina...
A cold front will move southward across North Carolina today.
Large-scale ascent will generally be weak, though isolated
convective development may occur as the front encounters greater
low-level moisture and sea breeze boundaries over coastal/eastern
North Carolina. Deep-layer shear within a northwesterly mid-level
flow regime will be sufficient for organized thunderstorms, but poor
mid-level lapse rates should tend to limit updraft intensity and the
overall severe threat. Regardless, any thunderstorms that can
develop and be sustained in this regime could produce locally gusty
winds and small hail mainly across near-coastal far eastern North
Carolina.

..Guyer/Weinman.. 09/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Sep 14 20:02:02 2026

ACUS01 KWNS 142001
SWODY1
SPC AC 142000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Mon Sep 14 2026

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
KANSAS AND SOUTHERN/EASTERN NEBRASKA INTO WESTERN/CENTRAL IOWA...

...SUMMARY...
Scattered strong to severe thunderstorms should occur across parts
of eastern Nebraska into western/central Iowa this afternoon and
evening. Large hail, severe wind gusts, and tornadoes all appear
possible. Severe thunderstorm winds will also be possible across northern/western Kansas.

...20z Update...
Visible satellite shows an expansive area of persistent mid-level
cloud cover over much of Nebraska and adjacent regions of northwest
Kansas and western Iowa. Some attempts at surface-based convection
are apparent over portions of south-central Nebraska. Latest surface mesoanalysis shows destabilization is occurring across much of
Kansas where skies are clear, with northward advancement now
occurring into central/eastern Nebraska as evidenced by 2232 J/kg of
MUCAPE in an 18z OAX observed sounding. This trend expected continue
into the early evening, with rapid destabilization occurring across
southeast Nebraska and southwest Iowa as the low-level jet shifts
east and intensifies.

An elongated area of convection is still expected to develop, from north-central Kansas into south-central/eastern Nebraska and
west-central Iowa, favoring supercell modes early. Despite the noted convective/environmental trends, the exact placement of convective
initiation remains uncertain, as exhibited in the most recent
HRRR/RRFS runs. Additionally, most guidance continues to suggest a
quick transition to mainly clusters/line segments. Therefore, no
changes were made in this outlook.

..Karstens/Wendt.. 09/14/2026

.PREV DISCUSSION... /ISSUED 1145 AM CDT Mon Sep 14 2026/

...Central Plains to Iowa...
Well to the northeast of a warm front, semi-extensive elevated
convection continues at midday across Iowa and the eastern Dakotas
into western/southern Minnesota, although there has been a
diminishing trend, and cloud cover otherwise remains semi-prevalent
across Nebraska and western/northern Kansas.

A key forecast uncertainty remains the spatial location of primary
late-day surface-based destabilization and uncertain likelihood of
deep convective development toward/just after peak heating. The
semi-persistent convection, residual cloud cover, and
autumnal-approaching sun angle (and ramifications for air mass
recovery) may be factors for confining the most-favorable environment/surface-based potential to eastern Nebraska and western
Iowa.

This will be as a seasonably strong mid-level shortwave trough and
50-70+ kt mid-level jet spread quickly east-northeastward across the
northern Plains and Canadian Prairies today. While the primary
surface low will likely persist across western Kansas, a secondary
surface wave may materialize across east-central/northeast Nebraska.
Greater low-level moisture across Kansas and the lower Missouri
Valley quickly spread north-northeastward in tandem with a warm
front, although its exact late-day disposition/placement is a bit
uncertain. This will precede a cold front that will sweep
southeastward across the northern/central Plains through tonight. A
narrow corridor of moderate to strong instability (MLCAPE 2000-3000+
J/kg) still appears plausible across eastern Nebraska and western
Iowa into the 21-00Z time frame, coincident and roughly dependent
upon surface temperatures warming into at least the low to mid 80s
F.

Robust thunderstorms should develop along or just ahead of the cold
front by late afternoon/early evening across eastern Nebraska, with strengthening/favorable deep-layer shear for supercells initially.
Large hail may occur, but modest lapse rates aloft and a quick mode
transition to mainly clusters/line segments will probably limit the spatial/temporal extent of the hail threat. Most guidance continues
to show a favorable conditional environment for tornadoes across
eastern Nebraska/western Iowa as the supercells/clusters spread
quickly eastward this evening, with a 40-50 kt low-level jet aiding
the development of ample effective SRH. But, various RAP forecast
soundings across this region show lingering low-level inhibition,
and it remains unclear whether convection will be able to fully take
advantage of the strong low-level shear. Even with this uncertainty,
a sustained surface-based supercell in this environment would
conditionally be capable of producing a strong tornado.

Otherwise, severe/damaging winds should become an increasing concern
as clusters develop and spread east-northeastward this evening, with
other late-day high-based development also expected in vicinity of a pre-frontal boundary across southern Nebraska and northern/western
Kansas. Regarding the eastern Nebraska/western Iowa regime, weak
instability with eastward extent in eastern Iowa and vicinity should
limit the severe risk deeper into the night. While deep-layer shear
will be somewhat weaker with southward extent across the central
Plains, at least isolated severe wind gusts may also occur with high-based/loosely organized convection that develops this afternoon
from eastern Colorado into western/northern Kansas along a surface
trough.

...Southwest/Four Corners...
Scattered thunderstorm development will occur later today from
western Colorado and southeast Utah into parts of Arizona/New Mexico
as a fairly moist low-level airmass gradually destabilizes. Modestly
enhanced mid-level westerly flow should be present this afternoon
over parts of Utah/Colorado, though it is uncertain if diurnal
heating and related instability will be sufficient for an organized
severe risk. Still, isolated gusty winds and small to perhaps
near-severe hail could occur with the strongest thunderstorms.
Farther south, flow will be weaker across Arizona, resulting in
mostly disorganized convection. Even so, localized strong gusts
appear possible, especially where stronger heating occurs and
steeper low-level lapse rates develop during the afternoon. Overall,
confidence in an organized severe risk is too low to include 5%
hail/wind probabilities.

...Eastern North Carolina...
A cold front will move southward across North Carolina today.
Large-scale ascent will generally be weak, though isolated
convective development may occur as the front encounters greater
low-level moisture and sea breeze boundaries over coastal/eastern
North Carolina. Deep-layer shear within a northwesterly mid-level
flow regime will be sufficient for organized thunderstorms, but poor
mid-level lapse rates should tend to limit updraft intensity and the
overall severe threat. Regardless, any thunderstorms that can
develop and be sustained in this regime could produce locally gusty
winds and small hail mainly across near-coastal far eastern North
Carolina.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 15 00:58:28 2026

ACUS01 KWNS 150058
SWODY1
SPC AC 150056

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 PM CDT Mon Sep 14 2026

Valid 150100Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WESTERN/CENTRAL IA AND FAR NORTHWEST MO...

...SUMMARY...
Strong to severe storms remain possible tonight across parts of the
central Plains and Midwest, with the greatest remaining threat
expected from western into central Iowa.

...Western/northern KS into southeastern NE/IA/northwest MO...
A broken band of thunderstorms is ongoing this evening from western
KS into eastern NE and western IA. The western portion of this band
may pose a localized severe-wind threat through dusk across
western/northern KS, in the presence of a remnant well-mixed
boundary layer and moderate deep-layer flow.

Farther east, a narrow corridor of rich low-level moisture and
moderate buoyancy resides from northeast KS/northwest MO into far
southeast NE and southwest IA. Low-level shear/SRH remains locally
enhanced across in the vicinity of the effective warm front,
conditionally supporting tornadic supercell potential. However,
ongoing convection has already become outflow dominant, and residual
downstream MLCINH may continue to limit surface-based supercell
potential this evening. Even if tornado potential does not evolve,
the environment otherwise remains favorable for damaging winds and
isolated hail as storms move eastward through the evening.

Convection will become increasingly elevated with eastward extent
late tonight, though the strongest cells/clusters may remain capable
of producing isolated hail and localized strong/damaging gusts into
the early morning hours. Other bands or clusters of elevated storms
will also be possible in the wake of earlier convection across the
central Plains, with moderate elevated buoyancy potentially
supporting a brief/localized severe threat overnight.

..Dean.. 09/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 15 05:28:42 2026

ACUS01 KWNS 150528
SWODY1
SPC AC 150526

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 AM CDT Tue Sep 15 2026

Valid 151200Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTH-CENTRAL PLAINS INTO PARTS OF THE MIDWEST...

...SUMMARY...
Strong to locally severe thunderstorms may occur from the
south-central Plains into parts of the Midwest this afternoon and
evening, with at least isolated damaging wind gusts possible.

...South-central Plains into parts of the Midwest...
A vigorous mid/upper-level trough will move quickly eastward across
Ontario and the Upper Great Lakes region today, before reaching
southern Hudson Bay and Quebec by this evening. A deep surface low
will accompany this system, as a trailing cold front moves across
parts of the central Plains and Midwest. To the south of the
ejecting trough, an upper ridge is forecast to amplify over the
Southeast.

Persistent clouds and precipitation to the cool side of the front
will help to reinforce the baroclinic zone as it moves southeastward
through the day. The front will impinge on an increasingly warm and
unstable environment by late afternoon, and scattered storm
development is expected from the TX Panhandle into parts of the
Midwest. The strongest mid/upper-level flow will be displaced north
of the front, and low-level flow will tend to weaken through the
day.

This weakening flow regime, combined with gradual midlevel height
rises and an eventual tendency for storms to be undercut by the
front, results in uncertainty regarding the magnitude of the
organized severe threat this afternoon and evening. However,
seasonably strong heating and relatively large PW and buoyancy will
support potential for localized downbursts and outflow-driven
clusters, with attendant damaging-wind potential. Hail potential
appears generally limited by weak midlevel lapse rates and only
modest deep-layer shear, though small to near-severe hail may occur
with the strongest cells.

A relatively broad Marginal Risk has been maintained from the
south-central Plains into the Midwest. Corridors of locally greater
potential could eventually evolve within the broader risk area,
especially near any pre-frontal outflow boundaries generated by
early-day convection.

...Parts of UT/western CO...
Anomalous moisture will remain in place across parts of the Four
Corners region and Southwest today. The strongest deep-layer
flow/shear will reside from UT into western CO, in advance of a
mid/upper-level trough over the Pacific Northwest. While a few
strong storms will be possible, generally weak heating and
destabilization are currently expected to limit the magnitude of the
severe threat. Small hail and gusty winds could accompany the
strongest storms.

..Dean/Supinie.. 09/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 15 12:30:44 2026

ACUS01 KWNS 151230
SWODY1
SPC AC 151228

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0728 AM CDT Tue Sep 15 2026

Valid 151300Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS INTO THE MIDWEST...

...SUMMARY...
Strong to locally severe thunderstorms may occur from the
south-central Plains into parts of the Midwest this afternoon and
evening, with at least isolated damaging wind gusts possible.

...Southern/Central Plains into the Midwest/Great Lakes...
The primary mid/upper-level trough over central/eastern Canada will
remain displaced well north of the surface warm sector today, with
upper ridging remaining anchored over the Southeast. A surface cold
front will make generally slow south-southeastward progress over the
central Plains and mid MS Valley/Midwest through this evening,
before eventually stalling late in the period. A seasonably moist
airmass characterized by surface dewpoints in the 60s to low 70s
will be in place ahead of the front from the southern High Plains
northeastward to the southern Great Lakes vicinity. While lapse
rates aloft will remain modest, daytime heating will support the
development of moderate instability by mid afternoon along much of
the length of the front (perhaps locally stronger across parts of
eastern KS into MO/IL).

Enhanced mid-level flow will tend to remain north of the cold front,
but some veering and gradual strengthening of the wind field with
height through mid levels should support sufficient deep-layer shear
for modest updraft organization, especially from parts of the
central Plains into the Midwest. Current expectations are for
thunderstorms to gradually develop by 20-23Z along/near much of the
length of the front as convective temperatures are reached. Loosely
organized clusters capable of producing mainly damaging winds should
be the primary concern as this convection spreads generally
east-northeastward through the evening, especially where low-level
lapse rates can become steepened. This appears more likely across
parts of the southern/central Plains where stronger heating is
forecast. Some chance for marginal supercell structures may exist
from parts of eastern KS into MO this afternoon, with isolated hail
possible. Considered greater wind probabilities and a Slight Risk
across this region, but potential for an organized cluster remains
too uncertain for an upgrade with this update.

...Southwest/Four Corners...
A rather moist low-level airmass (surface dewpoints generally in the
50s) will remain across parts of the Four Corners region today.
Modestly enhanced west-southwesterly mid-level flow will persist
from UT into western CO ahead of a mid/upper-level trough over the
Pacific Northwest. While occasional strong thunderstorms appear
possible, modest heating and overall weak destabilization are
currently expected to limit the magnitude of the severe threat.
Small hail and gusty winds could accompany the strongest cores, but
confidence in organized severe thunderstorms remains too low to
include any hail/wind probabilities at this time.

..Gleason/Mead.. 09/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 15 16:19:14 2026

ACUS01 KWNS 151618
SWODY1
SPC AC 151617

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1117 AM CDT Tue Sep 15 2026

Valid 151630Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF THE CENTRAL PLAINS AND MIDWEST....

...SUMMARY...
Strong to locally severe thunderstorms may occur from the
south-central Plains into parts of the Midwest this afternoon and
evening, with at least isolated damaging wind gusts possible.

...Central Plains into Midwest...
Moderately fast zonal flow remains across the northern US today,
with the primary surface boundary extending from the TX Panhandle east-northeastward into parts of KS/MO/IL. This boundary will be
enhanced by daytime differential heating, and will provide the focus
for scattered thunderstorms along its length. Most of this activity
will be relatively disorganized, but in an environment of moderate
CAPE and steep low-level lapse rates favorable for occasional
strong/severe downdrafts.

One area of greater concern extends across northern MO into
west-central IL. Morning CAM solutions suggest higher confidence in
storm coverage in this area, and forecast soundings show sufficient
deep-layer shear for organized multicell or occasional supercell
structures. However, much of this activity may occur on the north
side of the baroclinic zone with slightly weaker support for intense
downburst winds. Warm temperatures aloft should limit hail concern.
Therefore, have opted to maintain the MRGL risk category and
re-evaluate at the 20z update.

..Hart/Chalmers.. 09/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Sep 15 19:57:00 2026

ACUS01 KWNS 151956
SWODY1
SPC AC 151955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Tue Sep 15 2026

Valid 152000Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF THE CENTRAL PLAINS AND MIDWEST...

...SUMMARY...
Strong to locally severe thunderstorms may occur from the
south-central Plains into parts of the Midwest this afternoon and
evening, with at least isolated damaging wind gusts possible.

...20z Update...

...Southern Great Plains into parts of the Midwest...
The forecast remains generally on track with only minor adjustments
made to the existing outlook. Locally greater potential for a couple
of damaging/severe wind gusts may exist across portions of
south-central Kansas and northern Missouri where guidance continues
to depict greater storm coverage in the vicinity of a surface cold
front. The general displacement of enhanced deep-layer shear to the
north of the boundary and better thermodynamic profiles farther to
the south limits confidence regarding the occurrence of more than
isolated damaging/severe wind gusts, however. Thus, have opted
against a categorical upgrade with this outlook cycle. See MCDs
#2300 and #2301 as well as the discussion below for additional
details.

...Great Basin...
Isolated to widely scattered thunderstorms have formed across
portions of the Four Corners region as of 1930 UTC. Latest objective
analysis and regional observed 18z soundings indicate that weak
buoyancy has developed amid deep, well-mixed boundary layer
profiles. While these thermodynamic profiles may support an isolated
strong to perhaps severe thunderstorm or two this afternoon,
relatively weak low-level flow and fairly nebulous synoptic forcing
for ascent are expected to preclude a more concentrated area of
severe potential.

..Chalmers/Weinman.. 09/15/2026

.PREV DISCUSSION... /ISSUED 1117 AM CDT Tue Sep 15 2026/

...Central Plains into Midwest...
Moderately fast zonal flow remains across the northern US today,
with the primary surface boundary extending from the TX Panhandle east-northeastward into parts of KS/MO/IL. This boundary will be
enhanced by daytime differential heating, and will provide the focus
for scattered thunderstorms along its length. Most of this activity
will be relatively disorganized, but in an environment of moderate
CAPE and steep low-level lapse rates favorable for occasional
strong/severe downdrafts.

One area of greater concern extends across northern MO into
west-central IL. Morning CAM solutions suggest higher confidence in
storm coverage in this area, and forecast soundings show sufficient
deep-layer shear for organized multicell or occasional supercell
structures. However, much of this activity may occur on the north
side of the baroclinic zone with slightly weaker support for intense
downburst winds. Warm temperatures aloft should limit hail concern.
Therefore, have opted to maintain the MRGL risk category and
re-evaluate at the 20z update.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 16 01:01:42 2026

ACUS01 KWNS 160101
SWODY1
SPC AC 160059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Tue Sep 15 2026

Valid 160100Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
WESTERN TEXAS AND NORTHWESTERN OKLAHOMA TO THE SOUTHERN GREAT
LAKES...

...SUMMARY...
A couple of severe thunderstorms, accompanied by a severe wind and
hail threat, remain possible this evening across the southern High
Plains to the southern Great Lakes.

...Synopsis...
A broad upper ridge remains in place across the central and eastern
CONUS, with a low-amplitude trough currently located over the
Pacific Northwest. Ahead of the upper trough, a 500 mb jet streak,
accompanying a mid-level impulse, is currently overspreading the
Upper MS Valley. As a result, weak surface troughing and northward
low-level moisture advection are supporting a band scattered
thunderstorms along the west-northwestern periphery of the upper
ridge. Stronger flow aloft glancing the upper ridge periphery, amid
moderate buoyancy, will support a few strong to severe thunderstorms
for a few more hours, from the southern High Plains to the Lower
Great Lakes.

...Southern High Plains...
Pulse cellular and multicellular clusters, with a history of severe
gusts, continue to traverse a mixed boundary layer, characterized by
low to mid 90s F surface temperatures. Despite the persistent warm temperatures, nocturnal cooling should eventually reduce severe gust
potential. In the meantime, 1500+ J/kg DCAPE will promote adequate
evaporative cooling potential with the stronger storm cores to
support a short-duration severe gust threat.

...Northwestern OK to the southern Great Lakes...
Scattered to widespread thunderstorms remain in progress along the west-northwest periphery of the upper ridge. Given the 500 mb jet
streak over the Upper MS Valley, 30-40 kts of effective bulk shear
is overspreading the upper ridge periphery, especially over northern
MO, where the strongest storms are currently located. 1000-2000 J/kg
MLCAPE overlapping the aforementioned shear will continue to promote multicellular clusters and a couple of supercells, accompanied by a
severe wind and hail threat for at least a few more hours.

..Squitieri.. 09/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 16 05:55:12 2026

ACUS01 KWNS 160554
SWODY1
SPC AC 160553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Wed Sep 16 2026

Valid 161200Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER NORTHERN
UTAH AND EASTERN PARTS OF THE OHIO VALLEY...

...SUMMARY...
A couple of strong to severe thunderstorms appear possible across
northern Utah and eastern parts of the Ohio Valley today.

...Synopsis...
A mid-level anticyclone will prevail over the southern Plains to the
TN Valley as a stationary upper trough morphs into a cut-off upper
low along the West Coast today. Multiple mid-level impulses will
pivot around the anticyclone and overspread the Midwest to OH
Valley, supporting occasional rounds of showers and thunderstorms.
Given rich low-level moisture along the northern periphery of the
mid-level anticyclone, a couple of strong to severe storms may
occur. A few strong to severe storms may also occur over portions of
northern UT as a pronounced mid-level impulse rotates around the
developing West Coast upper low, resulting in overlapping cooler
temperatures and stronger flow aloft.

...Northern UT...
As the aforementioned impulse pivots around the evolving upper low,
a 50+ kt 500 mb jet streak and corresponding 7 C/km mid-level lapse
rates will overspread northern UT during the day. Surface heating
will be limited given widespread cloud cover. Nonetheless, forecast
soundings suggest that surface temperatures near 70 F may yield
MLCAPE as high as 1500 J/kg given steep tropospheric lapse rates.
Furthermore, stronger winds aloft that gradually veer with height
will yield around 50 kts of effective bulk shear and elongated
hodographs with some low-level curvature. Multicells and perhaps
embedded supercells should be the primary storm mode, capable of
isolated instances of severe wind and/or hail.

...Midwest into the OH Valley...
Multiple rounds of showers and thunderstorms will be ongoing at the
start of the period (12Z Wednesday) and will continue through the
period (to 12Z Thursday). Some intensification of storms may occur
over OH and immediate surrounding areas with one weak impulse by
afternoon peak heating. Assuming some appreciable insolation can
occur, surface temperatures may rise through the 80s F, amid 70s F
dewpoints, contributing to 1500-2500 J/kg MLCAPE. Given meager
vertical wind shear, mainly pulse cellular and multicellular storms
are expected. The stronger storm cores may produce wet downbursts,
accompanied by an isolated damaging gust threat.

Another mid-level impulse will traverse the Midwest overnight, with
several CAM guidance members supporting nocturnal convective
initiation over IA in the 03-12Z period. At the moment, the
evolution of this convection is uncertain, so no severe
probabilities have been added. However, should more established
convection develop overnight, an instance of marginally severe hail
cannot be completely ruled out.

..Squitieri/Supinie.. 09/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 16 12:47:08 2026

ACUS01 KWNS 161246
SWODY1
SPC AC 161245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Wed Sep 16 2026

Valid 161300Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST/OHIO VALLEY AND UTAH INTO FAR NORTHWEST COLORADO...

...SUMMARY...
Isolated strong to severe thunderstorms appear possible today across
parts of the Midwest/Ohio Valley and Utah/far northwest Colorado.

...Mid Mississippi Valley/Midwest into the Ohio Valley...
In between upper troughing over Canada and upper ridging over the
Southeast, a convectively augmented mid-level vorticity maximum over IL/northwest IN evident on radar imagery will track eastward today
across the OH Valley/southern Great Lakes. While mid-level westerly
winds will remain fairly modest across this region (generally 20-30
kt or less), this feature should aid additional convective
development this afternoon across parts of IN into OH and vicinity
as a moist low-level airmass gradually destabilizes. Poor lapse
rates aloft should tend to limit overall updraft strength, but
locally damaging winds may occur with any loosely organized clusters
that can form and spread eastward through the early evening before
weakening with the loss of daytime heating.

Most guidance continues to show thunderstorms developing late this
evening (mainly after 17/03Z) over portions of IA/northern IL in a
modest low-level warm advection regime. While MUCAPE will gradually
increase across this region as low-level moisture streams northward,
the potential for severe/damaging winds should tend to remain low
since convection will remain elevated and well north of a stalled
surface front. Cloud-layer shear also appears marginal to support
supercells with hail potential. Given these limiting factors, have
not included low severe probabilities at this time.

...Southwest into the Great Basin...
On the southeast periphery of a closed upper low centered over
northern CA, around 35-45 kt of southwesterly mid-level flow will
persist today across parts of the Great Basin. Ongoing thunderstorms
across eastern UT/northwest CO are occurring in a strongly sheared
but weakly unstable environment. While occasional hail could occur
with the stronger cores, current expectations are for renewed
thunderstorm development later this afternoon as the rather moist
low-level airmass gradually destabilizes with filtered diurnal
heating. If any cells/small clusters can form, they would pose an
isolated threat for severe hail/gusts. But, the limited
heating/instability should temper the overall severe risk.

Farther south across AZ/NM, numerous to widespread thunderstorms are
expected to develop and spread northward through the period as a
weak mid-level perturbation moves northward from the Baja California
vicinity across the Southwest/Four Corners. Above-average low-level
moisture (50s/60s surface dewpoints) is already in place over these
areas, but modest lapse rates aloft and limited daytime heating due
to widespread cloud cover suggest that instability will remain weak.
Nearly unidirectional/southerly flow and modest strengthening with
height through mid/upper levels should foster only marginal
deep-layer shear to support updraft organization. While occasional
gusty winds could occur with the stronger cores that develop, the
threat for severe gusts appears too limited to include any
probabilities with this update.

..Gleason/Mead.. 09/16/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Sep 16 16:14:38 2026

ACUS01 KWNS 161614
SWODY1
SPC AC 161612

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1112 AM CDT Wed Sep 16 2026

Valid 161630Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
NORTHERN UTAH...AND PARTS OF OHIO AND VICINITY....

...SUMMARY...
Isolated strong to severe thunderstorms appear possible today across
parts of the Midwest/Ohio Valley and Utah/far northwest Colorado.

...OH and Vicinity...
Morning visible satellite imagery shows broken cloud cover across
much of OH, which will allow pockets of heating/destabilization and
lead to moderate CAPE values by mid-afternoon. Widely scattered
thunderstorm development is expected, in a regime of relatively weak
westerly flow aloft and poor lapse rates. PWAT values approaching 2
inches and rather steep low-level lapse rates could result in
precip-loaded downdrafts capable of strong or occasionally damaging
winds.

...UT...
Moisture has increased across UT over the past 24 hours, with
dewpoints now in the low-mid 50s and PWAT values over 1 inch. This
along with ample heating will lead to scattered afternoon
thunderstorms. A band of 35-45 knot southwesterly mid-level winds
across this area will provide sufficient deep-layer shear for a few
rotating storms capable of hail and gusty winds.

..Hart/Chalmers.. 09/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Sep 16 19:34:44 2026

ACUS01 KWNS 161934
SWODY1
SPC AC 161932

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0232 PM CDT Wed Sep 16 2026

Valid 162000Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
NORTHERN UTAH AND PARTS OF OHIO AND VICINITY...

...SUMMARY...
Isolated strong to severe thunderstorms appear possible today across
parts of the Midwest/Ohio Valley and Utah/far northwest Colorado.

...20z Update...
The forecast remains generally on track with only minor changes made
to the existing outlook. See the discussion below for additional
details.

..Chalmers/Weinman.. 09/16/2026

.PREV DISCUSSION... /ISSUED 1112 AM CDT Wed Sep 16 2026/

...OH and Vicinity...
Morning visible satellite imagery shows broken cloud cover across
much of OH, which will allow pockets of heating/destabilization and
lead to moderate CAPE values by mid-afternoon. Widely scattered
thunderstorm development is expected, in a regime of relatively weak
westerly flow aloft and poor lapse rates. PWAT values approaching 2
inches and rather steep low-level lapse rates could result in
precip-loaded downdrafts capable of strong or occasionally damaging
winds.

...UT...
Moisture has increased across UT over the past 24 hours, with
dewpoints now in the low-mid 50s and PWAT values over 1 inch. This
along with ample heating will lead to scattered afternoon
thunderstorms. A band of 35-45 knot southwesterly mid-level winds
across this area will provide sufficient deep-layer shear for a few
rotating storms capable of hail and gusty winds.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 17 00:52:46 2026

ACUS01 KWNS 170052
SWODY1
SPC AC 170050

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 PM CDT Wed Sep 16 2026

Valid 170100Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY AND IN NORTH-CENTRAL UTAH...

...SUMMARY...
Isolated strong to severe thunderstorms will be possible early this
evening across parts of the Ohio Valley and in north-central Utah.

...Ohio Valley...
The latest water vapor imagery shows a distinct low-amplitude
shortwave trough in southwest Ontario extending southward toward the
Ohio Valley. At the surface, a quasi-stationary front is located
from central Illinois east-northeastward into central Ohio. The
shortwave trough is providing large-ascent, supportive of scattered thunderstorms ongoing near the front mainly across Ohio. South of
the front, surface dewpoints are in the mid 70s F, which is
contributing to moderate instability with MLCAPE estimated by the
RAP in the 1500 to 2000 J/kg range. The Wilmington, Ohio 00Z
sounding has 0-3 km lapse rates near 7.5 C/km, and the latest
WSR-88D VWP from Wilmington has 0-6 km shear in the 30 to 35 knot
range. This should be sufficient for a marginal severe threat for a
couple more hours this evening, with isolated wind damage possible.

...North-central Utah...
An upper-level low-pressure system is currently located near the
West Coast. Water vapor imagery shows a dry slot along the
southeastern periphery of the system from southern California into
western Utah. Thunderstorms are forming along the eastern edge of
the dry slot across north-central Utah, where large-scale ascent
appears to be maximized. Surface dewpoints in the 50s F with 500 mb temperatures near -8 C are contributing to weak instability in
north-central Utah, with MLCAPE estimated by the RAP around 1000
J/kg. RAP forecast soundings suggest that low to mid-level lapse
rates are near 7 C/km. This should be steep enough, along with
moderate deep-layer shear, for isolated severe wind gusts and hail
early this evening.

..Broyles.. 09/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 17 05:49:10 2026

ACUS01 KWNS 170549
SWODY1
SPC AC 170547

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Thu Sep 17 2026

Valid 171200Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE INTERMOUNTAIN WEST AND IN THE CENTRAL HIGH PLAINS...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible in parts of the Intermountain West late this afternoon and
early this evening. A few strong gusts may also occur in parts of
the central High Plains.

...Intermountain West...
An upper-level low will move inland into the Intermountain West
today, as southwest flow remains at mid-levels over much of the
region. At the surface, a trough will deepen from southern Idaho
into western Utah. To the east of the trough, dewpoints in the 50s
F, will contribute to weak instability by afternoon. As surface
temperatures warm, thunderstorms will develop in the higher terrain.
RAP forecast soundings to the east of the trough at 00Z have 0-6 km
shear in the 30 to 40 knot range. In addition, low to mid-level
lapse rates are forecast to be in the 6.5 to 7.5 C/km range. This
environment will likely support an isolated threat for severe gusts
and hail. The threat should be concentrated during the late
afternoon and early evening, as cell coverage maximizes near the
instability axis.

...Central High Plains...
An upper-level ridge will move eastward today across the
north-central U.S, as a shortwave trough embedded in the ridge moves
through the central High Plains. At the surface, a warm front is
forecast to move slowly northward across southern and western
Nebraska this afternoon. An axis of moisture, with surface dewpoints
in the 60s and 70s F, will be oriented north of the front from the
mid Missouri Valley west-northwestward into the central High Plains.
During the late afternoon, scattered thunderstorms are expected to
develop near the shortwave trough, with storms moving gradually
northeastward across the central High Plains. Forecast soundings
near the area of greatest expected convective coverage have moderate
deep-layer shear suggesting an isolated severe threat will be
possible. However, lapse rates are forecast to be poor, which should
keep any severe threat marginal. If storms near the front can remain
nearly surface-based, then an isolated wind-damage threat could
develop, mainly during the early to mid evening, as low-level flow
increases.

..Broyles/Thornton.. 09/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 17 12:35:40 2026

ACUS01 KWNS 171232
SWODY1
SPC AC 171230

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Thu Sep 17 2026

Valid 171300Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
UTAH/IDAHO INTO SOUTHWEST MONTANA...AND THE CENTRAL HIGH PLAINS...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible over parts of the Intermountain West this afternoon and
evening. A few strong to severe gusts may also occur across portions
of the central High Plains.

...Utah/Idaho into Southwest Montana...
A closed mid/upper-level low over northern CA this morning will
slowly develop eastward today across the northern Intermountain
region. A 40-50 kt southwesterly mid-level jet and difluence aloft
will overspread parts of the northern Great Basin through this
afternoon. Large-scale ascent will likewise further increase through
the day across this region, with additional thunderstorm development anticipated. The primary uncertainty regarding the severe risk
remains how much instability will develop given the prevalence of
clouds and ongoing precipitation this morning. With upper 40s to low
50s surface dewpoints already in place, some guidance suggests
sufficient diurnal heating in tandem with cool temperatures aloft
will support up to 1000-1250 J/kg of MLCAPE over southeast
ID/northern UT and vicinity this afternoon. If this occurs, then a
focused corridor of greater severe hail/wind potential may exist
across these areas, as deep-layer shear will be strong enough to
support supercells. Otherwise, a broader risk for isolated
hail/gusty winds will exist across the northern Great Basin with any cells/small clusters that can develop.

...Central High Plains...
Between a mid/upper-level low over the West Coast and upper ridging
over the Southeast/southern Plains, multiple minor mid-level
perturbations should move northeastward from the Southwest/southern
Rockies towards the central High Plains by this evening. One leading
mid-level vorticity maximum aiding showers and isolated
thunderstorms across NM this morning should support additional
convective development across northeast CO into western NE and
vicinity by late afternoon. While low-level moisture and related
instability should gradually increase across this region through the
day, mid-level lapse rates should remain modest. This will probably
tend to limit updraft intensity, but sufficient deep-layer shear
should be present for some convective organization. A small cluster
or two could eventually evolve and pose some risk for isolated
severe gusts as they spread east-northeastward across the central
High Plains through the evening.

...Midwest/Ohio Valley into the Mid-Atlantic...
Ongoing convection across the Midwest has remained slightly elevated
to the north of a surface front through the early morning. Current
expectations are for this activity to move east-southeastward
through the rest of the morning in a weakly unstable environment.
Various observed 00/12Z soundings downstream across the OH Valley
and southern Mid-Atlantic show very poor lapse rates aloft (i.e.,
around 4.7-5 C/km in the 700-500 mb layer), which will likely hinder
robust updraft intensities. Furthermore, visible satellite imagery
shows extensive cloudiness present across these regions. This will
slow/dampen diurnal heating and related steepening of low-level
lapse rates. While strong/gusty winds may still occur with
convection that develops/spreads southeastward through the day, the
overall risk for severe/damaging winds appears too limited for 5%
probabilities at this time.

..Gleason/Mead.. 09/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 17 16:12:44 2026

ACUS01 KWNS 171612
SWODY1
SPC AC 171610

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1110 AM CDT Thu Sep 17 2026

Valid 171630Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER PARTS OF IDAHO/UTAH...AND A SMALL PART OF THE
CENTRAL HIGH PLAINS....

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible over parts of the Intermountain West this afternoon and
evening. A few strong to severe gusts may also occur across portions
of the central High Plains.

...ID/UT...
Morning water vapor imagery shows an upper low over northern CA,
with a band of strong flow aloft with associated embedded shortwave
troughs extending across NV into UT/ID. Strong heating across this
area will aid in the development of scattered thunderstorms from
southern ID into northern UT by mid-afternoon. Sufficient vertical
shear is present for rotating updrafts capable of large hail and
gusty/damaging winds. While coverage of storms will likely be
limited, one or two severe cells are expected later today - mainly
over the eastern Snake River Plain.

...CO/KS/NE...
The remnants of a weak tropical low are tracking northeastward
across the four-corners region this morning. Ample moisture and
weak ascent associated with this feature will lead to considerable
clouds and scattered thunderstorms today over the mountains of CO
and southern WY. This activity will spread eastward into eastern CO
and western NE/KS with high-based convection posing a risk of
locally damaging wind gusts. The extent of this severe threat will
be modulated by daytime heating, which is uncertain at this time due
to lingering cloud cover.

..Hart/Chalmers.. 09/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Sep 17 19:49:12 2026

ACUS01 KWNS 171949
SWODY1
SPC AC 171947

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Thu Sep 17 2026

Valid 172000Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER PARTS OF IDAHO/UTAH AND A SMALL PART OF THE CENTRAL
HIGH PLAINS...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible over parts of the Intermountain West this afternoon and
evening. A few strong to severe gusts may also occur across portions
of the central High Plains.

...20z Update...
No changes were made to the existing outlook with this update as the
forecast remains generally on track. See MCD #2304 and the
discussion below for additional information.

..Chalmers/Weinman.. 09/17/2026

.PREV DISCUSSION... /ISSUED 1110 AM CDT Thu Sep 17 2026/

...ID/UT...
Morning water vapor imagery shows an upper low over northern CA,
with a band of strong flow aloft with associated embedded shortwave
troughs extending across NV into UT/ID. Strong heating across this
area will aid in the development of scattered thunderstorms from
southern ID into northern UT by mid-afternoon. Sufficient vertical
shear is present for rotating updrafts capable of large hail and
gusty/damaging winds. While coverage of storms will likely be
limited, one or two severe cells are expected later today - mainly
over the eastern Snake River Plain.

...CO/KS/NE...
The remnants of a weak tropical low are tracking northeastward
across the four-corners region this morning. Ample moisture and
weak ascent associated with this feature will lead to considerable
clouds and scattered thunderstorms today over the mountains of CO
and southern WY. This activity will spread eastward into eastern CO
and western NE/KS with high-based convection posing a risk of
locally damaging wind gusts. The extent of this severe threat will
be modulated by daytime heating, which is uncertain at this time due
to lingering cloud cover.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 18 00:43:22 2026

ACUS01 KWNS 180043
SWODY1
SPC AC 180041

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 PM CDT Thu Sep 17 2026

Valid 180100Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL HIGH PLAINS AND INTERMOUNTAIN WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible over parts of the Intermountain West early this evening. A
few strong to severe gusts may also occur across parts of the
central High Plains.

...Intermountain West...
An upper-level low is currently located over northern California,
evident on water vapor imagery. Mid-level flow is southwesterly over
much of the Intermountain West with a dry slot located from southern
Nevada northeastward into northern Utah and southeast Idaho.
Scattered thunderstorms have developed within the nose of the dry
slot from north-central Utah into eastern Idaho. Within this zone,
the RAP has a pocket of instability with MLCAPE in the 1000 to 1200
J/kg range. In addition, the WSR-88D VWP near Pocatello, Idaho has
0-6 km shear near 40 knots. RAP forecast soundings in the vicinity
have low to mid-level lapse rates around 8 C/km. This environment
should support a threat for hail and isolated severe gusts for a
couple more hours this evening.

...Central High Plains...
On water vapor imagery, a mid-level shortwave trough is currently
located in the central Rockies. This feature will move into the
central High Plains this evening. At the surface, a warm front is
located from northern Kansas into southwest Nebraska. The front will
move northward into west-central Nebraska this evening. To the north
of the front, a moist axis is present with surface dewpoints from
the mid 60s to the lower 70s F. Near the moist axis, the RAP has
MLCAPE in the 1500 to 2000 J/kg range. In addition, the regional
WSR-88D VWP near North Platte has 0-6 km shear around 45 knots,
which will support an isolated wind-damage threat for a few more
hours this evening. Lapse rates are poor which will keep any severe
threat marginal.

..Broyles.. 09/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 18 05:57:52 2026

ACUS01 KWNS 180557
SWODY1
SPC AC 180555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Fri Sep 18 2026

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE CAROLINAS INTO NORTHERN GEORGIA...IN THE MID MISSOURI VALLEY AND
IN THE INTERMOUNTAIN WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts may develop late this
afternoon and early this evening from the Carolinas into northern
Georgia, and in the mid Missouri Valley. Isolated severe gusts and
hail will also be possible in parts of the Intermountain West.

...Carolinas/Northern Georgia...
At the surface, a cold front will move southward into the
Mid-Atlantic today. Ahead of the front, a moist airmass will be in
place over much of the Carolinas extending southwestward into
northern Georgia. Surface dewpoints within this airmass will be in
the 60s to near 70 F. As surface temperatures warm today, an axis of
moderate instability will develop along the moist axis. In response
to surface heating, scattered thunderstorms will form in the higher
terrain of the southern Appalachians and move southward into the
southern Appalachian foothills. The thermodynamic environment may be
enough to support an isolated wind-damage threat, mainly in the late
afternoon and early evening when low-level lapse rates become
steepest.

...Eastern Nebraska/Iowa...
Mid-level heights will gradually fall today over much of the
north-central U.S., as a ridge pattern breaks down. At the surface,
a well-defined moist axis will be in place from the mid Mississippi
Valley northwestward into the mid Missouri Valley. Surface dewpoints
along and near this axis will be in the lower to mid 70s F. In
response to surface heating, a reservoir of moderate instability
will be in place by afternoon over much of Iowa. Low-level
convergence is forecast to become maximized during the afternoon
along the instability axis, and further west to near a surface low
over the mid Missouri Valley. Thunderstorm development will be most
likely this afternoon on the northern end of the stronger
instability from far southeast Minnesota into northern Iowa. Enough
instability and deep-layer shear should be in place for isolated
severe wind gusts. Although conditional, the threat could develop
southwestward over the remainder of Iowa during the early evening,
as a low-level jet strengthens across the region.

...Intermountain West...
A mid-level trough will move eastward across the Intermountain West
today. Southwest flow aloft will be in place ahead of the trough
over much of the region. At the surface, dewpoints in the 50s F are
expected from northern Utah into valleys of western Wyoming, where
the RAP is forecasting MLCAPE to peak in the 1000 to 1200 J/kg
range. In addition to the instability, forecast soundings show
moderate deep-layer shear in response to the approaching mid-level
trough. As low to mid-level lapse rates become steep in the late
afternoon and early evening, isolated severe gusts and hail will be
possible.

..Broyles/Thornton.. 09/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 18 12:22:00 2026

ACUS01 KWNS 181221
SWODY1
SPC AC 181219

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0719 AM CDT Fri Sep 18 2026

Valid 181300Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE CAROLINAS INTO NORTHERN GEORGIA...PARTS OF THE CENTRAL HIGH PLAINS...IOWA...AND IN THE INTERMOUNTAIN WEST...

...SUMMARY...
An isolated severe risk is forecast later today into the evening for
the Carolinas into northern Georgia, Iowa, parts of the central High
Plains, and parts of the Intermountain West.

...Carolinas/Northern Georgia...
A cluster of weak thunderstorms ongoing this morning over KY-WV near
a surface front will continue southward via northerly steering flow
on the eastern periphery of a mid-level anticyclone centered over
the Ark-La-Tex. A weak upper impulse associated with this activity
may influence a rejuvenation of storms near the leading edge of
convective outflow across the VA/NC border vicinity. As the
boundary layer heats to the south of the front, other scattered
storms are expected to develop over the Piedmont into northern GA
this afternoon. Isolated strong to locally severe gusts (50 to 60
mph) capable of wind damage may occur with the stronger thunderstorm
cores.

...Iowa...
Surface mesoanalysis this morning places a front draped from the
lower OH Valley westward into the mid MO Valley with an accompanying
weak surface low over western NE. Seasonably moist low levels
(lower 70s F surface dewpoints) are south of the boundary across the
lower OH Valley west-northwestward into eastern NE. The boundary is
forecast to gradually advance north-northeastward through IA during
the period driven by a persistent belt of 30+ kt flow via a
southwesterly 850 mb jet, thereby maintaining a corridor of
low-level warm-air advection across the area. Model guidance
signals higher probabilities for thunderstorm activity over IA into
far southern MN where low-level forcing and heating will locally
erode convective inhibition. Although marginally severe gusts will
probably be the primary hazard, enlarged hodographs near the warm
front may yield a localized risk for a couple of weak, short-lived
supercells [longer-lived supercell structures limited by weak
(20-kt) flow above 500 mb]. Upscale growth into a larger convective
system may occur during the late evening into the overnight, but
will likely become increasingly displaced from appreciable buoyancy
as it moves towards the southwest Great Lakes.

...Intermountain West...
A mid-level trough will move eastward across the Intermountain West
today. Southwest flow aloft will be in place ahead of the trough
over much of the region. At the surface, dewpoints in the 50s F are
expected from northern Utah into valleys of western Wyoming, where
the RAP is forecasting MLCAPE to peak in the 1000 to 1200 J/kg
range. In addition to the instability, forecast soundings show
moderate deep-layer shear in response to the approaching mid-level
trough. As low to mid-level lapse rates become steep in the late
afternoon and early evening, isolated severe gusts and hail will be
possible.

...Central High Plains...
Radar mosaic and water-vapor imagery this morning show a
convectively enhanced, mid-level vorticity maximum moving
north-northeast over central NM. This disturbance is forecast to
possibly influence storm development later today into this evening
in a primarily post-frontal regime over the central High Plains.
Ample heating of the boundary layer over eastern CO into adjacent
portions of southwest NE/northwest KS will precondition an
environment as initially isolated to widely scattered storms
potentially grow upscale into a small, eastward-moving cluster this
evening. Isolated severe gusts may accompany the stronger outflow
surges with this activity.

..Smith/Mead.. 09/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 18 16:30:50 2026

ACUS01 KWNS 181630
SWODY1
SPC AC 181629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Fri Sep 18 2026

Valid 181630Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
CAROLINA PIEDMONT INTO NORTHERN GEORGIA...NORTHERN IOWA...PARTS OF
THE CENTRAL HIGH PLAINS...AND PARTS OF THE INTERMOUNTAIN WEST...

...SUMMARY...
An isolated severe risk is forecast later today into the evening for
the Carolinas into northern Georgia, northern Iowa, parts of the
central High Plains, and parts of the Intermountain West.

...Carolina Piedmont into Northern Georgia...
Recent surface analysis places a wavy stationary front from southern
IL through southern IN and southern OH into southwest PA. Decaying
showers and thunderstorms currently precede this boundary from
southern IL into northern KY. This boundary is forecast to shift
southward today in response to a modest surge of cooler air in the
wake of a shortwave trough moving through southern Quebec and the
Canadian Maritimes. This front will be relatively weak, but
thunderstorm development is still anticipated this afternoon as the
front interacts with the warm, moist, and diurnally destabilized
airmass across the Carolina Piedmont and northern GA. Vertical shear
will be weak and a largely outflow-dominant storm mode is expected.
Even so, the strong buoyancy and ample moisture (i.e. PW values over
2 inches) will support the potential for occasionally strong
downbursts.

...Central High Plains...
Water-vapor imagery continues to show a convectively enhanced
vorticity maximum moving north-northeast from north-central NM into
southern CO. This vorticity max is forecast to continue
northeastward along the periphery of the upper ridging centered over
east TX, contributing to thunderstorm development from eastern WY
through eastern CO this afternoon/evening. Much of this activity
will occur in regions of cooler surface temperatures and/or more
limited low-level moisture. However, surface-based buoyancy could
exists in the CO/NE/KS border intersection vicinity, where a
combination of strong heating, and lingering post-frontal low-level
moisture will exist. Potential exists for initially isolated to
widely scattered storms to grow upscale into a small,
eastward-moving cluster this evening. Isolated severe gusts may
accompany the stronger outflow surges with this activity.

...Intermountain West...
Continued thunderstorm development is anticipated across the region
today, with overall coverage and intensity increasing as a shortwave
trough continues to move eastward into southern ID and northern UT.
Some moderate, filtered daytime heating is possible, but the overall
region is expected to remain relatively cool (i.e. high temperatures
ranging from the upper 60s across southern ID to the low to mid 70s
across northern UT). Even so, cold temperatures aloft will support
enough buoyancy, which will combine with strong deep-layer vertical
shear to support occasionally strong/organized updrafts. Strong to
severe gusts will be possible with any stronger, more persistent
storms. Some instances of small hail are possible as well.

...Northern Iowa into Far Southern MN...
Elevated thunderstorm development is still anticipated tonight,
supported by warm-air advection associated with a moderate low-level
jet that extends through the region. Highest storm coverage will
likely be displaced north and east of the strongest buoyancy. Even
so, a few of the southernmost storms could occur where moderate
vertical shear and buoyancy are in place, supporting the potential
for an isolated supercell or two. Primary risk with any stronger
storms is hail, but a strong gust or two is possible if any more
linear structures develop.

..Mosier/Chalmers.. 09/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Sep 18 19:43:56 2026

ACUS01 KWNS 181943
SWODY1
SPC AC 181941

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0241 PM CDT Fri Sep 18 2026

Valid 182000Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
CAROLINA PIEDMONT INTO NORTHERN GEORGIA...NORTHERN IOWA...PARTS OF
THE CENTRAL HIGH PLAINS...AND PARTS OF THE INTERMOUNTAIN WEST...

...SUMMARY...
An isolated severe risk continues for portions of the Carolinas into
northern Georgia and parts of the Intermountain West. Isolated
severe storms are also forecast later today across portions of
northern Iowa and parts of the central High Plains.

...20z Update...
Only minor adjustments were made to the existing outlook as the
forecast remains generally on track. See the discussion below and
MCDs #2306 and #2307 for additional information.

...Central High Plains...
As a mid-level vorticity maximum progresses north-northeastward
across the central High Plains later this evening, some modest
enhancement of deep-layer shear may support an isolated risk for
small to marginally severe hail in addition to isolated severe
gusts. This risk appears conditional on a more cellular storm mode
persisting farther northeastward where it can interact with more
favorable low-level moisture, however. Thus, while some
consideration was given to the additional of hail probabilities
within the existing Marginal Risk, the overall hail risk appears to
be generally less than 5%.

..Chalmers/Wendt.. 09/18/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Fri Sep 18 2026/

...Carolina Piedmont into Northern Georgia...
Recent surface analysis places a wavy stationary front from southern
IL through southern IN and southern OH into southwest PA. Decaying
showers and thunderstorms currently precede this boundary from
southern IL into northern KY. This boundary is forecast to shift
southward today in response to a modest surge of cooler air in the
wake of a shortwave trough moving through southern Quebec and the
Canadian Maritimes. This front will be relatively weak, but
thunderstorm development is still anticipated this afternoon as the
front interacts with the warm, moist, and diurnally destabilized
airmass across the Carolina Piedmont and northern GA. Vertical shear
will be weak and a largely outflow-dominant storm mode is expected.
Even so, the strong buoyancy and ample moisture (i.e. PW values over
2 inches) will support the potential for occasionally strong
downbursts.

...Central High Plains...
Water-vapor imagery continues to show a convectively enhanced
vorticity maximum moving north-northeast from north-central NM into
southern CO. This vorticity max is forecast to continue
northeastward along the periphery of the upper ridging centered over
east TX, contributing to thunderstorm development from eastern WY
through eastern CO this afternoon/evening. Much of this activity
will occur in regions of cooler surface temperatures and/or more
limited low-level moisture. However, surface-based buoyancy could
exists in the CO/NE/KS border intersection vicinity, where a
combination of strong heating, and lingering post-frontal low-level
moisture will exist. Potential exists for initially isolated to
widely scattered storms to grow upscale into a small,
eastward-moving cluster this evening. Isolated severe gusts may
accompany the stronger outflow surges with this activity.

...Intermountain West...
Continued thunderstorm development is anticipated across the region
today, with overall coverage and intensity increasing as a shortwave
trough continues to move eastward into southern ID and northern UT.
Some moderate, filtered daytime heating is possible, but the overall
region is expected to remain relatively cool (i.e. high temperatures
ranging from the upper 60s across southern ID to the low to mid 70s
across northern UT). Even so, cold temperatures aloft will support
enough buoyancy, which will combine with strong deep-layer vertical
shear to support occasionally strong/organized updrafts. Strong to
severe gusts will be possible with any stronger, more persistent
storms. Some instances of small hail are possible as well.

...Northern Iowa into Far Southern MN...
Elevated thunderstorm development is still anticipated tonight,
supported by warm-air advection associated with a moderate low-level
jet that extends through the region. Highest storm coverage will
likely be displaced north and east of the strongest buoyancy. Even
so, a few of the southernmost storms could occur where moderate
vertical shear and buoyancy are in place, supporting the potential
for an isolated supercell or two. Primary risk with any stronger
storms is hail, but a strong gust or two is possible if any more
linear structures develop.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 19 00:47:58 2026

ACUS01 KWNS 190047
SWODY1
SPC AC 190045

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 PM CDT Fri Sep 18 2026

Valid 190100Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSOURI VALLEY...CENTRAL HIGH PLAINS AND INTERMOUNTAIN
WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts will be possible this
evening across parts of the mid Missouri Valley and Central High
Plains. A few severe wind gusts and hail may occur in parts of the Intermountain West.

...Mid Missouri Valley...
An upper-level ridge is currently present in the central U.S, with a
30 to 40 knot low-level jet located near the ridge in the mid
Missouri Valley. Isolated thunderstorms have developed early this
evening in eastern Nebraska, near the axis of the low-level jet.
Surface dewpoints in eastern Nebraska are in the lower to mid 70s F,
with the RAP showing MLCAPE in the 1000 to 2000 J/kg range. While
the 00Z Omaha sounding has 0-6 km shear of 20 to 25 knots,
deep-layer shear is likely a bit stronger southward in the vicinity
of the low-level jet. This could be enough for an isolated
wind-damage threat. The threat may develop northeastward into
western and central Iowa this evening as low-level flow and
convective coverage both increase.

...Central Plains...
An anti-cyclonic flow pattern is present over much of the
north-central U.S. The eastern extension of a mid-level shortwave
trough, evident on water vapor imagery, is located over east-central
Colorado. Scattered thunderstorms are ongoing just ahead of the
trough from northeast Colorado into southwest Nebraska, where the
RAP has MLCAPE in the 1000 to 2000 J/kg range. The WSR-88D VWPs at
Goodland and Cheyenne have 0-6 km shear in the 30 to 40 knot range,
suggesting that an isolated severe threat will be possible early
this evening. Severe wind gusts will be the primary threat.

...Intermountain West...
On water vapor imagery, southwesterly mid-level flow is present from
the central Rockies into the central High Plains. A mid-level
shortwave trough appears to be located from near the Unita Mountains
in northeast Utah eastward into the central Rockies of Colorado.
Large-scale ascent associated with the trough is supporting
scattered thunderstorm development. The RAP shows the strongest
instability across northeast Utah and northwest Colorado, where
moderate deep-layer shear and modestly steep lapse rates are evident
on RAP analysis. This could be enough for an isolated potential for
severe wind gusts and hail over the next few hours.

..Broyles.. 09/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 19 06:36:24 2026

ACUS01 KWNS 190516
SWODY1
SPC AC 190514

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1214 AM CDT Sat Sep 19 2026

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains. Isolated severe wind gusts and hail may occur in parts of
the southern Plains and lower Missouri Valley. Isolated severe gusts
will also be possible from the Ohio Valley southward into the
Southeast.

...Central and Southern Plains/Lower Missouri Valley...
Mid-level heights will steadily fall over the central U.S. today, as southwesterly flow aloft becomes established over much of the
region. At the surface, a cold front will advance southeastward
across the central Plains, and should be positioned from central
Kansas to far northwest Missouri by late afternoon. Ahead of the
front, surface dewpoints will be mostly from the mid 60s to mid 70s
F. As surface temperatures warm today, the moisture will contribute
to moderate destabilization. Thunderstorm initiation will become
likely by late afternoon across central and eastern Kansas, as
low-level convergence increases along and ahead of the front. A
complex of organized storms is expected to become established by
early evening and should persist for several hours.

RAP forecast soundings by early evening near the instability axis
have 0-6 km shear in the 30 to 40 knot range, with substantial
directional shear in the low-levels. In addition, low to mid-level
lapse rates are forecast to become steep. This environment should
support a large hail threat with supercells. A wind-damage threat
will also be possible, especially if a line segment can persist and
become organized during the evening. A marginal severe threat may
also develop southwestward across parts of the southern High Plains,
where hail and isolated severe gusts will be possible in the late
afternoon and early evening.

...Central High Plains...
An upper-level trough will move eastward across the Intermountain
West today, as flow aloft remains southwesterly over the central
Rockies and central High Plains. At the surface, a cold front will
advance southward across southeastern Colorado and western Kansas.
Behind the front, surface dewpoints in eastern Colorado will be in
the upper 50s to lower 60s F. The moisture will enable moderate
destabilization over much of eastern Colorado by afternoon. Warming
surface temperatures will lead to scattered thunderstorm development
in the higher terrain, with this convection moving eastward into the
central High Plains during the late afternoon. RAP forecast
soundings at 21Z in eastern Colorado have 0-6 shear in the 35 to 40
knot range, with 700-500 mb lapse rates near 8 C/km. This
environment will likely support a threat for large hail with
supercells. Isolated severe wind gusts will also be possible. A
marginal severe threat may also develop further north into parts of
eastern Wyoming and far western Nebraska, but instability will
remain relatively weak there.

...Ohio Valley/Southern Appalachians/Southeast...
West-northwesterly mid-level flow will be located over much of the
northeastern third of the U.S today. At the surface, an axis of
low-level moisture will be oriented from the Ohio Valley southward
into the southern Appalachians, along which moderate instability is
expected to be in place by afternoon. Convective development will be
possible in parts of the airmass, where localized surface heating
and low-level convergence become maximized. Thunderstorms in areas
with moderate instability could produce isolated severe wind gusts,
mainly during the late afternoon and early evening.

..Broyles/Thornton.. 09/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 19 12:26:58 2026

ACUS01 KWNS 191226
SWODY1
SPC AC 191225

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0725 AM CDT Sat Sep 19 2026

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains.

...Central and Southern Plains/Lower Missouri Valley...
Larger-scale mid-level troughing over the Great Basin and central
Rockies will gradually shift eastward with falling heights spreading
east across the central Great Plains and lower MO Valley through
daybreak Sunday. A cold front draped in a general west-southwest to east-northeast orientation from central High Plains to the mid MS
Valley will slowly push south. A seasonably moist airmass ahead of
the boundary over KS/MO into northwestern OK will become moderately
unstable by mid afternoon. Scattered storm development is
eventually expected during the late afternoon and early evening as
convective inhibition is locally eroded. Steep 0-3 km lapse rates
(8.5-9.5 deg C/km) will aid in storm vigor and the potential for
strong evaporative cooling with the more intense cores. Have
introduced an intensity level 1 for the wind hazard (60-75 mph
gusts) where a combination of HREF ensemble guidance and higher PW
and lapse rates overlap. A few short-lived supercells are possible
given the adequate speed and directional shear according to model
forecast soundings across the KS vicinity. Large hail will be
possible with the stronger updrafts. This threat will likely
diminish during the evening.

...Central High Plains...
The airmass north of a cool front will heat/destabilize through
mid-late afternoon ahead of the aforementioned upper-level trough
impinging on the region from the west. Some easterly component to
the low-level flow will aid in maintaining a fetch of sufficient
moisture (mainly 50s deg F surface dewpoints) into much of the
central High Plains. Models indicate scattered storms developing
near/east of I-25 with increasing storm coverage expected through
the early evening. With time, a loosely organized band of a storms
(including some supercells) will probably grow upscale and
transition to a linear cluster as it moves east across eastern CO
into western KS. Have included 15-percent wind probabilities across
eastern CO to account for this favorable storm mode evolution for
severe gusts. There is some indication this activity may continue
into western KS during the late evening and early overnight,
prompting the inclusion of low severe-wind probabilities.
Uncertainty remains regarding the character/intensity of this
activity across western KS (e.g., 19/06z MPAS-HT), especially if the
depth of post-frontal airmass and near-surface static stability are
similar to the 19/06z NAM depiction.

...Ohio Valley/Southern Appalachians/Southeast...
West-northwesterly mid-level flow will be located over much of the
northeastern third of the U.S. today. At the surface, an axis of
low-level moisture will be oriented from the Ohio Valley southward
into the southern Appalachians, along which moderate instability is
expected to be in place by afternoon. Widely scattered to scattered
storms are forecast during the afternoon. A few of the stronger
downdrafts may be capable of a strong to locally severe wind-gust
threat (50 to 60 mph) capable of wind damage.

..Smith/Mead.. 09/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 19 16:31:28 2026

ACUS01 KWNS 191631
SWODY1
SPC AC 191629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat Sep 19 2026

Valid 191630Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS AND CENTRAL HIGH PLAINS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains.

...Ohio Valley...
Recent surface analysis places a weak low over northern IN, along
the northern end of an outflow boundary that is pushing southward/south-southeastward across central IL and central IN.
Airmass south of this boundary is very moist, with dewpoints
generally in the upper 60s to low 70s. Filtered heating is
anticipated across this region today, with the resulting warm and
moist conditions supporting moderate buoyancy. The strongest
buoyancy is expected from southern IN into southwest OH and adjacent
far northern KY. The surging character of the outflow combined with
limited deep-layer vertical shear results in uncertainty regarding
how thunderstorms will evolve this afternoon, with at least some
potential for a predominance of undercut, poorly organized updrafts.
That being said, potential also exists for just enough
buoyancy/shear balance for a few stronger, more persistent bowing
clusters. Steep low-level lapse rates will promote strong to severe
gusts with any more persistent line segments that develop.

...Southern Appalachians/Southeast...
Warm and moist conditions will support airmass destabilization and
the potential of afternoon/evening thunderstorms across the region.
The region is largely void of coherent surface features, so any
convective initiation would likely be tied to mesoscale areas of
low-level confluence. Widely scattered to scattered storms are
forecast during the afternoon, and a few stronger water-loaded
downdrafts capable of 50 to 60 mph gusts are possible.

...Central and Southern Plains/Lower Missouri Valley...
Recent surface analysis places a low over southwest IA, with a cold
front extending back southwestward through southwest KS and the
central OK Panhandle into the northwest TX Panhandle. This front is
expected to slowly push south while larger-scale mid-level troughing
over the Great Basin and central Rockies gradually shifts eastward.
A seasonably moist airmass is in place ahead of the cold front, and
moderate buoyancy is expected as this airmass heats and destabilizes
this afternoon.

Low-level convergence along the cold front, augmented by modest
large-scale forcing for ascent, will support scattered storm
development during the late afternoon and early evening as
convective inhibition is locally eroded. Given adequate speed and
directional shear, a few short-lived supercells are possible early
in the convective cycle, particularly across KS. Large hail will be
possible with the stronger updrafts. Thereafter, high-based storm
character coupled with steep low-level lapse rates will support
strong to severe gusts, including the potential for a few gusts of
60 to 75 mph.

...Central High Plains...
Low-level easterly flow across the central High Plains will help
maintain at least upper 50s/low 60s dewpoints across the region this afternoon/evening. The low-amplitude shortwave trough currently
moving through northern NV/UT is forecast to continue eastward,
interacting with this moist and unstable airmass to support
scattered thunderstorm development. With time, strengthening
mid-level flow will help support upscale growth from a loosely
organized band of a storms (including some supercells) to a more
organized linear cluster. Some hail is possible early with the more
cellular development, with wind gusts becoming more likely with
time. There is some indication this activity may continue into
western KS during the late evening and early overnight.

..Mosier/Chalmers.. 09/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Sep 19 20:05:02 2026

ACUS01 KWNS 192004
SWODY1
SPC AC 192003

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0303 PM CDT Sat Sep 19 2026

Valid 192000Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS AND CENTRAL HIGH PLAINS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this afternoon and evening across parts of the central
Plains.

...20z Update...

...Central High Plains into western Kansas...
Latest CAM and TLE guidance continue to provide some indications
that a linear cluster or two will persist into western, and perhaps
even central Kansas, after 00z tonight. This may allow a somewhat
greater risk for hail/wind gusts to persist farther west into
Kansas. Uncertainty regarding the evolution and downstream
persistence of these clusters through the overnight hours precludes
further expansion at this time, however.

...Central New Mexico...
Widely scattered thunderstorms with some marginal supercell
structures have formed across portions of central New Mexico over
the past 1-2 hours. The 18z ABQ observed sounding depicted around
750 J/kg MLCAPE with ~30 kts of effective shear and 700-500 mb lapse
rates around 7 C/km. While this could support a brief/localized
threat for damaging wind gusts and marginally severe hail,
observations and recent CAM/TLE guidance suggest the
spatial/temporal window for any localized severe risk remains quite
narrow. Thus, the general severe risk appears to be less than 5%
across this region.

...Ohio Valley...
Latest observations continue to depict a well defined outflow
boundary arching southwestward from north of Columbus, OH, into
southern IL/IN. Convection has largely struggled to sustain along
this boundary, likely owing to the surging character of the outflow
and limited deep-layer wind shear. The northern edge of the Level
1/Marginal Risk area was trimmed slightly where temperatures well
behind the outflow boundary have fallen into the upper-70s F and are
thus expected to limit further convective development this
afternoon/evening.

Elsewhere, the forecast remains generally on track, with only minor
changes made to the existing outlook. See the discussion below and
MCDs #2309 and #2310 for additional information.

..Chalmers/Wendt.. 09/19/2026

.PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Sep 19 2026/

...Ohio Valley...
Recent surface analysis places a weak low over northern IN, along
the northern end of an outflow boundary that is pushing southward/south-southeastward across central IL and central IN.
Airmass south of this boundary is very moist, with dewpoints
generally in the upper 60s to low 70s. Filtered heating is
anticipated across this region today, with the resulting warm and
moist conditions supporting moderate buoyancy. The strongest
buoyancy is expected from southern IN into southwest OH and adjacent
far northern KY. The surging character of the outflow combined with
limited deep-layer vertical shear results in uncertainty regarding
how thunderstorms will evolve this afternoon, with at least some
potential for a predominance of undercut, poorly organized updrafts.
That being said, potential also exists for just enough
buoyancy/shear balance for a few stronger, more persistent bowing
clusters. Steep low-level lapse rates will promote strong to severe
gusts with any more persistent line segments that develop.

...Southern Appalachians/Southeast...
Warm and moist conditions will support airmass destabilization and
the potential of afternoon/evening thunderstorms across the region.
The region is largely void of coherent surface features, so any
convective initiation would likely be tied to mesoscale areas of
low-level confluence. Widely scattered to scattered storms are
forecast during the afternoon, and a few stronger water-loaded
downdrafts capable of 50 to 60 mph gusts are possible.

...Central and Southern Plains/Lower Missouri Valley...
Recent surface analysis places a low over southwest IA, with a cold
front extending back southwestward through southwest KS and the
central OK Panhandle into the northwest TX Panhandle. This front is
expected to slowly push south while larger-scale mid-level troughing
over the Great Basin and central Rockies gradually shifts eastward.
A seasonably moist airmass is in place ahead of the cold front, and
moderate buoyancy is expected as this airmass heats and destabilizes
this afternoon.

Low-level convergence along the cold front, augmented by modest
large-scale forcing for ascent, will support scattered storm
development during the late afternoon and early evening as
convective inhibition is locally eroded. Given adequate speed and
directional shear, a few short-lived supercells are possible early
in the convective cycle, particularly across KS. Large hail will be
possible with the stronger updrafts. Thereafter, high-based storm
character coupled with steep low-level lapse rates will support
strong to severe gusts, including the potential for a few gusts of
60 to 75 mph.

...Central High Plains...
Low-level easterly flow across the central High Plains will help
maintain at least upper 50s/low 60s dewpoints across the region this afternoon/evening. The low-amplitude shortwave trough currently
moving through northern NV/UT is forecast to continue eastward,
interacting with this moist and unstable airmass to support
scattered thunderstorm development. With time, strengthening
mid-level flow will help support upscale growth from a loosely
organized band of a storms (including some supercells) to a more
organized linear cluster. Some hail is possible early with the more
cellular development, with wind gusts becoming more likely with
time. There is some indication this activity may continue into
western KS during the late evening and early overnight.

$$

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From COD Weather Processor @1:2320/107 to All on Sun Sep 20 00:58:56 2026

ACUS01 KWNS 200058
SWODY1
SPC AC 200057

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Sat Sep 19 2026

Valid 200100Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTH-CENTRAL
KANSAS TO NORTHWEST MISSOURI...AND IN FAR WESTERN KANSAS...

...SUMMARY...
Thunderstorms with scattered severe wind gusts and large hail are
possible this evening across parts of the central Plains and Lower
Missouri Valley.

...Southern and Central Plains/Lower Missouri Valley...
The latest water vapor imagery shows a mid-level trough over the
Intermountain West, with southwesterly flow aloft from the southern
and central Rockies eastward into much of the Great Plains. A
shortwave trough appears to be located in central Kansas, close to
the position of a front oriented from southwest to northeast across
the central Plains. Near and to the southeast of the boundary,
surface dewpoints are in the 60s and lower 70s F, which is
contributing to moderate instability. The RAP shows an axis of
MLCAPE in the 1500 to 2500 J/kg range from central Kansas
northeastward into northwest Missouri and southern Iowa...see MCD
2312. Scattered strong to severe storms are ongoing along the
southwestern part of this corridor of moderate instability...see MCD
2311.

The 00Z sounding at Topeka has MLCAPE near 2000 J/kg with 0-6 km
shear around 20 knots, and a 0-3 km lapse rate just above 7.5 C/km.
RAP analysis suggests that deep-layer shear is stronger near the
front. The environment will support a continued severe threat this
evening. Severe wind gusts and isolated large hail will be the
primary threats. The line that is currently developing in northeast
Kansas may continue to have a severe threat later this evening as it
tracks northeastward into northwest Missouri and far southern Iowa.
A marginal wind-damage threat will extend southwestward along a
surface trough into parts of west Texas.

In the central High Plains, the western edge of moderate instability
extends westward into far western Kansas. Scattered strong storms
are ongoing near the Colorado-Kansas state line where the RAP has
MLCAPE around 1500 J/kg. The Goodland WSR-88D VWP has 0-6 km shear
around 50 knots, and the RAP has 700-500 mb lapse rates in western
Kansas near 7.5 C/km. This will support a supercell threat this
evening with a potential for isolated large hail. Severe wind gusts
will also be possible...see MCD 2313.

..Broyles.. 09/20/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sun Sep 20 05:27:54 2026

ACUS01 KWNS 200521
SWODY1
SPC AC 200519

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1219 AM CDT Sun Sep 20 2026

Valid 201200Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
OKLAHOMA AND FROM EASTERN COLORADO INTO FAR WESTERN KANSAS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail will be possible
this afternoon and evening across parts of Oklahoma and from eastern
Colorado into far western Kansas. Isolated severe gusts and hail
will also be possible in parts of the southern Plains, and from the
Ozarks eastward into the Ohio Valley.

...Southern Plains...
At mid-levels, southwesterly flow will be in place today over much
of the central U.S. A shortwave trough is forecast to move into
Kansas and Oklahoma this afternoon. At the surface, a low will
deepen over southwest Oklahoma today, as a cold front advances
southward into central Oklahoma. Near the front, surface dewpoints
will be in the mid to upper 60s F, which will allow moderate
instability to develop by afternoon. MLCAPE is forecast to peak in
the 2000 to 3000 J/kg range in much of central and eastern Oklahoma.
As surface temperatures warm and low-level convergence increases,
scattered thunderstorms are expected to develop in the afternoon,
with storms moving from the Low Rolling Plains and Red River Valley northeastward into central and eastern Oklahoma.

RAP forecast soundings at 00Z near the instability axis in central
Oklahoma have MLCAPE around 3000 J/kg with 0-6 km shear near 30
knots, and 700-500 mb lapse rates in the 7 to 7.5 C/km range.
Although a mixed mode is expected, the environment will likely
support supercell development in areas that become locally
favorable. Large hail and severe wind gusts will be possible with
supercells. The potential for supercells may continue into the early
evening over east-central Oklahoma, but a gradual transition to
linear mode is expected to take place. The wind-damage threat could
become maximized in the early evening, if an organized line segment
can develop.

...Central High Plains...
A mid-level shortwave trough will move into the central High Plains
today. Ahead of this feature, a lee surface trough will deepen
during the day from northeast New Mexico into eastern Colorado.
Surface dewpoints near the surface trough will be in the 50s F,
which will enable moderate destabilization by afternoon. As surface temperatures warm, convection will initiate in the higher terrain
during the early afternoon and move eastward into the lower
elevations. A small complex of storms will likely develop from this
convection over the central High Plains. RAP forecast soundings near
the instability axis in eastern Colorado at 00Z have MLCAPE near
1500 J/kg with 0-6 km around 40 knots, and 700-500 mb lapse rates
near 7.5 C/km. This environment should be capable of producing
supercells with large hail and severe wind gusts.

...Ozarks/Mid Mississippi and Ohio Valleys...
At mid-levels, a subtle anticyclonic flow pattern will be in place
from the Ozarks eastward into the Ohio Valley. At the surface, an
axis of moisture and instability will be located from central
Missouri eastward into southern Indiana and southern Ohio, along
which surface dewpoints will be in the 70s F. By mid to late
afternoon, MLCAPE is forecast to peak in the 2000 to 3000 J/kg range
along much of this corridor. Although large-scale ascent will remain
relatively limited, increasing low-level convergence near the moist
axis will result in isolated convective initiation. Any small
cluster that can develop and persist in the late afternoon and early
evening could produce isolated severe wind gusts.

..Broyles/Thornton.. 09/20/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sun Sep 20 12:28:54 2026

ACUS01 KWNS 201228
SWODY1
SPC AC 201227

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0727 AM CDT Sun Sep 20 2026

Valid 201300Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
OKLAHOMA AND FROM EASTERN COLORADO INTO FAR WESTERN KANSAS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail will be possible
this afternoon and evening across parts of Oklahoma and from eastern
Colorado into far western Kansas. Isolated severe gusts and hail
will also be possible in parts of the southern Plains, and from the
Ozarks eastward into the Ohio Valley.

...OK and TX...
Southwesterly upper-level flow over the southern Great Plains will
be downstream of an eastward-migrating upper trough moving into the
central and southern High Plains by early evening. A frontal zone
modulated by convection overnight over the eastern part of the TX
Panhandle and OK will sag southward through tonight. A moist
airmass will undergo appreciable heating amidst surface dewpoints
in the mid to upper 60s F, resulting in moderate buoyancy by mid
afternoon. Sufficient deep-layer shear for storm organization is
expected across OK, where a risk for severe wind gusts and some hail
is expected to evolve during the afternoon into the early evening.
The 20/00z HREF/REFS ensemble guidance showed agreement in
delineating the strongest explicit 10-m wind gusts across parts of
southern OK within a corridor characterized by very steep 0-3 km
lapse rates. Have introduced an intensity level-1 area where
confidence in 60-80 mph gusts is greatest.

...Central High Plains...
A mid-level shortwave trough will move into the central High Plains
today. An easterly component to low-level flow north of the surface
front will maintain a fetch of moisture (50s deg F surface
dewpoints), and this moisture combined with heating will enable
moderate destabilization by afternoon. As surface temperatures warm
and convective inhibition erodes, scattered storms are forecast by
mid-late afternoon. Model forecast soundings show straight
hodographs with sizable CAPE in the -10 to -30 deg C layer. As a
result, a few supercells are probable with the primary severe hazard
being large hail (1 to 2.5 inches in diameter) along with isolated
severe gusts. Some lingering severe risk may eventually develop
over southeast CO late this evening and spread into the OK Panhandle
overnight.

...Ozarks/Mid Mississippi and Ohio Valleys...
A series of low-amplitude perturbations will move generally east
across the Ozarks and OH Valley to the north of a weakened mid-level anticyclone centered over the northwest Gulf Coast. A reservoir of
seasonally rich low-level moisture (mid 60s to low 70s deg F surface
dewpoints) will exist south a cold front that was analyzed near the
I-70 corridor this morning. This frontal zone is forecast to
gradually push southward during the period and serve as the northern
delimiter of strong/severe thunderstorm activity.

As the boundary layer heats through the mid afternoon to the south
of more extensive cloud cover with north extent, moderate buoyancy
will likely develop. Some modest enhancement to mid-level flow will
probably accompany the aforementioned convectively augmented
mid-level features. Portions of eastern IL into IN could perhaps
yield a slightly more favorable environment for severe storms due to
hodograph structure. Yet, it remains uncertain whether some
strengthening of low-level flow in vicinity of the effective frontal
zone occurs later today. The 19/06z NAM differed substantially
versus recent RAP model runs. Regardless, a few clusters of strong
to severe thunderstorms will probably evolve, posing mainly an
isolated threat for wind damage.

..Smith/Mead.. 09/20/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sun Sep 20 16:28:30 2026

ACUS01 KWNS 201628
SWODY1
SPC AC 201626

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1126 AM CDT Sun Sep 20 2026

Valid 201630Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL AND EASTERN OKLAHOMA...AND FROM EASTERN COLORADO INTO FAR
WESTERN KANSAS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail will be possible
this afternoon and evening across parts of Oklahoma and from eastern
Colorado into far western Kansas. Isolated severe gusts and hail
will also be possible in parts of the southern Plains, and from the
Ozarks eastward into the Ohio Valley.

...Central/North TX into central/eastern OK...
Surface analysis places a low over central OK, along a cold front
that arcs from northeast OK into southwest OK and then back up
through the central TX Panhandle. This low also precedes a shortwave
trough moving into western OK. The cold front is forecast to shift southward/southeastward today as the shortwave continues eastward.
The airmass ahead of this front will be warm, moist, and moderately
buoyant, and thunderstorm development is expected from
central/eastern OK into central TX. Mid-level flow is slightly
stronger across OK, supporting a greater potential for strong to
severe storms. A more isolated severe risk exists across TX where a
more disorganized storm mode is likely. Primary threat is damaging
gusts from 55 to 65 mph.

...Central High Plains...
An easterly component to low-level flow north of the surface front
will maintain a fetch of moisture (50s deg F surface dewpoints)
across eastern CO this afternoon. This moisture, combined with
heating and cool temperatures aloft, will enable moderate
destabilization by afternoon. Thunderstorm development is expected
as ascent attendant to the mid-level cyclone over WY persists across
the region. Moderate mid-level westerly flow will also persist
throughout the base of this cyclone, resulting in moderate to strong
vertical shear across the region this afternoon and evening. Storm
coverage is expected to remain isolated to widely scattered (largely
due to cooler surface temperatures and some lingering convective
inhibition), but any storms that do form and mature will likely be supercellular. Primary severe hazard is large hail (1 to 2.5 inches
in diameter), but isolated severe gusts are possible as well. Some
lingering severe risk may eventually develop over southeast CO late
this evening and spread into the OK Panhandle overnight.

...Ozarks into the Mid Mississippi and Ohio Valleys...
Recent surface analysis places lows over central PA, central IL,
central MO, and central OK. An arcing stationary boundary extends
between these features, with this boundary largely demarcated by a
subtle wind shift. Current water vapor satellite imagery shows
several convectively augmented vorticity maxima within this corridor
as well. These vorticity maxima are forecast to progress
eastward/northeastward along the northern periphery of a weakened
mid-level anticyclone centered over the northwest Gulf Coast,
augmenting low-level convergence and helping to support
afternoon/evening thunderstorms from the OH Valley into
central/southern MO.

Despite ample low-level moisture, relatively warm temperatures aloft
will likely mitigate the overall buoyancy. Even so, steep low-level
lapse rates and moderate mid-level flow could still support some
bowing line segments capable of damaging gusts. Highest thunderstorm
coverage this afternoon and evening is expected from
central/southern IN into southern OH, with another corridor of
relatively higher coverage developing across central MO later this
evening as well. Both of these corridors are downstream of a
previously mentioned vorticity max, and represent areas of greater
severe potential.

..Mosier/Chalmers.. 09/20/2026

$$

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From COD Weather Processor @1:2320/107 to All on Sun Sep 20 19:46:40 2026

ACUS01 KWNS 201946
SWODY1
SPC AC 201944

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0244 PM CDT Sun Sep 20 2026

Valid 202000Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL AND EASTERN OKLAHOMA AND FROM EASTERN COLORADO INTO FAR
WESTERN KANSAS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail remain possible
this afternoon and evening across parts of Oklahoma and from eastern
Colorado into far western Kansas. Isolated severe gusts and hail
will also be possible in parts of the southern Plains and from the
Ozarks eastward into the Ohio Valley.

...20z Update...
The forecast remains generally on track, with only minor adjustments
made to the existing outlook. See the discussion below for
additional information.

..Chalmers/Wendt.. 09/20/2026

.PREV DISCUSSION... /ISSUED 1126 AM CDT Sun Sep 20 2026/

...Central/North TX into central/eastern OK...
Surface analysis places a low over central OK, along a cold front
that arcs from northeast OK into southwest OK and then back up
through the central TX Panhandle. This low also precedes a shortwave
trough moving into western OK. The cold front is forecast to shift southward/southeastward today as the shortwave continues eastward.
The airmass ahead of this front will be warm, moist, and moderately
buoyant, and thunderstorm development is expected from
central/eastern OK into central TX. Mid-level flow is slightly
stronger across OK, supporting a greater potential for strong to
severe storms. A more isolated severe risk exists across TX where a
more disorganized storm mode is likely. Primary threat is damaging
gusts from 55 to 65 mph.

...Central High Plains...
An easterly component to low-level flow north of the surface front
will maintain a fetch of moisture (50s deg F surface dewpoints)
across eastern CO this afternoon. This moisture, combined with
heating and cool temperatures aloft, will enable moderate
destabilization by afternoon. Thunderstorm development is expected
as ascent attendant to the mid-level cyclone over WY persists across
the region. Moderate mid-level westerly flow will also persist
throughout the base of this cyclone, resulting in moderate to strong
vertical shear across the region this afternoon and evening. Storm
coverage is expected to remain isolated to widely scattered (largely
due to cooler surface temperatures and some lingering convective
inhibition), but any storms that do form and mature will likely be supercellular. Primary severe hazard is large hail (1 to 2.5 inches
in diameter), but isolated severe gusts are possible as well. Some
lingering severe risk may eventually develop over southeast CO late
this evening and spread into the OK Panhandle overnight.

...Ozarks into the Mid Mississippi and Ohio Valleys...
Recent surface analysis places lows over central PA, central IL,
central MO, and central OK. An arcing stationary boundary extends
between these features, with this boundary largely demarcated by a
subtle wind shift. Current water vapor satellite imagery shows
several convectively augmented vorticity maxima within this corridor
as well. These vorticity maxima are forecast to progress
eastward/northeastward along the northern periphery of a weakened
mid-level anticyclone centered over the northwest Gulf Coast,
augmenting low-level convergence and helping to support
afternoon/evening thunderstorms from the OH Valley into
central/southern MO.

Despite ample low-level moisture, relatively warm temperatures aloft
will likely mitigate the overall buoyancy. Even so, steep low-level
lapse rates and moderate mid-level flow could still support some
bowing line segments capable of damaging gusts. Highest thunderstorm
coverage this afternoon and evening is expected from
central/southern IN into southern OH, with another corridor of
relatively higher coverage developing across central MO later this
evening as well. Both of these corridors are downstream of a
previously mentioned vorticity max, and represent areas of greater
severe potential.

$$

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From COD Weather Processor @1:2320/107 to All on Mon Sep 21 01:02:12 2026

ACUS01 KWNS 210101
SWODY1
SPC AC 210100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Sun Sep 20 2026

Valid 210100Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL HIGH PLAINS....

...SUMMARY...
Thunderstorms with large hail and severe wind gusts will be possible
this evening across parts of the central High Plains. A few severe
wind gusts may also occur from the Ozarks northeastward into the
Ohio Valley.

...Central High Plains...
The latest water vapor imagery shows a shortwave mid-level trough
over eastern Colorado. An axis of moderate instability, with MLCAPE
in the 1500 to 2000 J/kg range, is analyzed by the RAP just ahead of
this feature from near the Colorado-Kansas state line southeastward
into the Oklahoma Panhandle. An isolated supercell is currently
ongoing near the instability axis near Lamar, Colorado. RAP forecast
soundings ahead of this cell across far southwest Kansas early this
evening have MLCAPE in the 1500 to 2000 J/kg range, 0-6 km shear
near 40 knots and 700-500 mb lapse rates around 7 C/km. This
environment will continue to support supercells capable of large
hail and wind damage. The threat could persist into the mid to late
evening with parts of southwest Kansas and the Oklahoma Panhandle
being affected. Later this evening, short-term model forecasts also
suggest that redevelopment may occur to the east of the Denver
Metro, with a new cluster potentially tracking southeastward near
the instability axis. This activity could also pose a large hail and
wind damage threat.

...Ozarks into the Ohio Valley...
Several minor perturbations, embedded in westerly flow aloft, appear
to moving through a corridor from the Ozarks eastward into the Ohio
Valley. The most pronounced feature appears to be located in
southeastern Indiana, ahead of which a small cluster of severe
storms is ongoing. Along the projected track of these storms, the
RAP has MLCAPE in the 1200 to 1500 J/kg range with 0-6 km around 35
knots. This should continue to support an isolated wind-damage
threat for a couple more hours early this evening...see MCD 2319.

Further southwest into the parts of the Ozarks and mid Mississippi
Valley, moderate instability is analyzed by the RAP from far
northeast Oklahoma northeastward into south-central Illinois.
Isolated to scattered thunderstorms are ongoing near the instability
axis. These storms may be capable of producing isolated severe wind
gusts for another hour or two this evening...see MCD 2318.

..Broyles.. 09/21/2026

$$

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