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000
ACUS11 KWNS 251852
SWOMCD
SPC MCD 251851
SDZ000-NEZ000-WYZ000-252045-

Mesoscale Discussion 0512
NWS Storm Prediction Center Norman OK
0151 PM CDT Thu Apr 25 2024

Areas affected...Southeast Wyoming into South Dakota and northwest
Nebraska

Concerning...Severe potential...Watch possible

Valid 251851Z - 252045Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms are expected to gradually intensify through
the afternoon hours across parts of southeast Wyoming, western South
Dakota, and northwest Nebraska. This activity will primarily pose a
severe hail risk, though a few severe gusts are also possible.

DISCUSSION...Over the past 1-2 hours, high-based convection
developing off the higher terrain of central WY, along with
additional convection along a deepening surface trough, has migrated
into a narrow plume of returning moisture noted in surface
observations (dewpoints in the low to mid 50s). Steep lapse rates
between 8-9 C/km noted in 12 UTC soundings remain entrenched over
the region with upper-level ascent increasing with the approach of
synoptic wave from the southwest. This combination of improving
moisture and steep lapse rates is supporting MLCAPE values upwards
of 1000 J/kg over a region with increasing ascent. Consequently,
thunderstorm coverage and intensity is forecast to increase through
the afternoon. While stronger mid-level flow is displaced to the
south, elongated hodographs featuring 30 knot winds near the 6 km
level should support organization of semi-discrete cells and
thunderstorm clusters with an attendant threat for large hail (most
likely between 0.75 to 1.5 inches in diameter). Additionally, 20-30
F dewpoint depressions indicate steep low-level lapse rates that
should support the potential for a few severe gusts - especially if
a more organized cluster with a consolidated cold pool can become
established.

..Moore/Hart.. 04/25/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LBF...UNR...CYS...

LAT...LON   41400497 42890500 43730424 45270256 45320203 44820147
            44430131 43640208 42700284 41700349 41140400 41100456
            41400497