ACUS11 KWNS 231924
SWOMCD
SPC MCD 231924 
NEZ000-SDZ000-NDZ000-232130-

Mesoscale Discussion 2100
NWS Storm Prediction Center Norman OK
0224 PM CDT Sun Aug 23 2026

Areas affected...southeast North Dakota...western South Dakota...and
portions of the Nebraska Panhandle

Concerning...Severe potential...Watch possible 

Valid 231924Z - 232130Z

Probability of Watch Issuance...60 percent

SUMMARY...The threat for severe storms capable of large hail up to
two inches and severe wind gusts up to 75 mph is expected to
increase by mid to late afternoon. A severe thunderstorm watch is
possible.

DISCUSSION...Visible satellite and lightning data indicate incipient
thunderstorm development over the Black Hills, which is being aided
by heating along the high terrain and convergence in the vicinity of
a surface low. The 18Z Rapid City sounding is likely representative
of the ambient environment, featuring modestly steep mid-level lapse
rates atop a moist boundary layer with MLCAPE of 1500-2000 J/kg and
some residual capping.  While deep-layer shear isn't particularly
strong, the 18Z Riverton, WY sounding sampled stronger winds above
5-6 km AGL, which will spread east into the region later this
afternoon.

Elsewhere, high-based convection is developing over portions of
southeast WY into the western NE Panhandle amidst a deeper,
well-mixed boundary. Deepening cumulus is also being observed over
far eastern MT, along and ahead of a weak surface trough. Latest
time-lagged HRRR and RRFS ensemble guidance indicates the potential
for widely scattered storms to evolve by mid to late afternoon from
parts of the western Dakotas into the NE Panhandle, which seems
reasonable based on the observational signals mentioned above.
Parameter space appears supportive of organized storm modes,
including supercells capable of large hail, potentially up to two
inches in diameter. Severe wind gusts up to 75 mph also appear
possible, especially with the storms moving into the NE Panhandle.

Convective trends are being monitored for a possible severe
thunderstorm watch.

..Mead/Smith.. 08/23/2026

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

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

LAT...LON   44000392 44660399 47280403 47290368 47130326 44500268
            42180209 41680239 41640291 42540322 43690382 44000392 

MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN