ACUS11 KWNS 301915
SWOMCD
SPC MCD 301914=20
NEZ000-SDZ000-COZ000-WYZ000-302115-

Mesoscale Discussion 0903
NWS Storm Prediction Center Norman OK
0214 PM CDT Sat May 30 2026

Areas affected...Parts of western NE/SD into northeast CO and
extreme eastern WY

Concerning...Severe potential...Watch possible=20

Valid 301914Z - 302115Z

Probability of Watch Issuance...60 percent

SUMMARY...The severe-storm threat is expected to increase later this
afternoon. Watch issuance is possible.

DISCUSSION...A negative-tilt mid/upper-level shortwave trough across
the central/northern Rockies will move east-northeastward toward the
High Plains through the afternoon. Southeasterly flow will maintain
low-level moisture transport into parts of western NE/SD and
adjacent northeast CO/eastern WY, to the north of a surface low near
the CO/KS border. Modest diurnal heating and steep midlevel lapse
rates are supporting MLCAPE of 1000-2000 J/kg, with locally greater
values across southwest NE.=20

The approaching shortwave trough will aid in scattered storm
development from late afternoon into the evening. Initial
development is ongoing in the Black Hills vicinity, and additional
storms may develop near a surface trough extending northward from
the surface low into northeast CO and the NE/CO/WY border region.
Deep-layer flow will remain generally modest, though some
enhancement to effective shear/SRH will be possible near any surface
boundaries and where stronger backing of low-level flow occurs.=20

Organized multicells and perhaps a couple supercells may evolve with
time, with an attendant threat of large hail and localized severe
gusts. The thermodynamic environment is conditionally favorable for
very large hail (especially across parts of western NE and northeast
CO), if any supercells can be sustained. A tornado or two also
cannot be ruled out, especially where low-level vorticity is
enhanced near any surface boundaries and the DCVZ. Watch issuance is
possible for parts of the region by mid/late afternoon.

..Dean/Hart.. 05/30/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8iCIP4ifT3iUE9kKbVQusr3yYw266UezEyeNDDsJPuX8yuboTYooqVXUuq9kUcStqrxfdKEDU= Sw7hFqgjBPJy-0kqek$ for graphic product...

ATTN...WFO...LBF...UNR...GLD...BOU...CYS...

LAT...LON 40090452 42480460 44620460 44760389 44760310 44640262
43380206 42410201 41250205 40640212 39900222 39830311
39850371 40090452=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


=3D =3D =3D
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