ACUS11 KWNS 122235
SWOMCD
SPC MCD 122234
NEZ000-SDZ000-130030-

Mesoscale Discussion 1959
NWS Storm Prediction Center Norman OK
0534 PM CDT Wed Aug 12 2026

Areas affected...southwestern South Dakota into northern Nebraska

Concerning...Severe Thunderstorm Watch 576...578...

Valid 122234Z - 130030Z

The severe weather threat for Severe Thunderstorm Watch 576, 578
continues.

SUMMARY...Damaging wind and large hail threat continues within WW576
and WW578.

DISCUSSION...A cluster of supercells continue southeastward across
southwestern South Dakota. These have produced hail up to 1.75
inches in diameter and damaging wind up to 87 mph. These will likely
continue to pose a risk for large hail and damaging wind downstream
over the next few hours, given the very favorably unstable and
deeply sheared environment across western Nebraska, where MLCAPE
around 1000-2400 J/kg and deep layer shear around 45-50 kts is
depicted by SPC Mesoanalyis. Trends in hi-res guidance suggest that
this cluster may eventually interact with convection coming out of
Colorado later this evening, with a continued damaging wind risk
through the evening.

..Thornton.. 08/12/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!8ziMWRf4cGuS4dz-Kb27yXXS9pruIu0L7pGHb-ZSaCzs9mJK_poZVxasUOt1D927fdrQkFbCZUtjkUUtcf3MoyuXfl4$ for graphic product...

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

LAT...LON 42880340 43090396 43350404 43540393 43640366 43700343
43750298 43760295 43640232 43310183 43050191 42910202
42860217 42810234 42880340

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


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--- scorpsmtpd
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