ACUS11 KWNS 190154

SWOMCD

SPC MCD 190154 

SDZ000-190330-



Mesoscale Discussion 2032

NWS Storm Prediction Center Norman OK

0854 PM CDT Tue Aug 18 2026



Areas affected...Parts of western/southwest SD



Concerning...Severe potential...Watch unlikely 



Valid 190154Z - 190330Z



Probability of Watch Issuance...20 percent



SUMMARY...An isolated severe hail/wind threat may continue this

evening. Watch issuance is unlikely.



DISCUSSION...A cell which formed earlier over the Black Hills in

western SD has recently intensified into a supercell while

approaching Rapid City. The 00Z UNR sounding showed relatively

modest instability (MUCAPE less than 1000 J/kg) and mid-level lapse

rates, but strong deep-layer shear around 50 kt. This ongoing

supercell should continue to pose a threat for severe hail in the

short term per recent MRMS MESH estimates. But, it remains unclear

whether it will be able to persist downstream of the higher terrain

of the Black Hills given increasing MLCIN with nocturnal cooling

occurring across southwest SD. Some short term guidance suggests a

small cluster may evolve over the next couple of hours, with some

increase in severe/damaging outflow winds possible if this occurs.

Regardless, the presence of weak instability and overall isolated

nature of the severe threat suggest that watch issuance is unlikely.



..Gleason.. 08/19/2026



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



ATTN...WFO...UNR...



LAT...LON   44100353 44470321 44110146 43350148 43080203 43180275

            43810362 44100353 



MOST PROBABLE PEAK WIND GUST...55-70 MPH

MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN