783  
ACUS11 KWNS 112248  
SWOMCD  
SPC MCD 112248  
SDZ000-120015-  
 
MESOSCALE DISCUSSION 1937  
NWS STORM PREDICTION CENTER NORMAN OK  
0548 PM CDT TUE AUG 11 2026  
 
AREAS AFFECTED...PARTS OF WESTERN SD  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 569...  
 
VALID 112248Z - 120015Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 569  
CONTINUES.  
 
SUMMARY...INTENSE SUPERCELLS WILL REMAIN CAPABLE OF PRODUCING MAINLY  
LARGE TO VERY LARGE HAIL (UP TO 2-3.5 INCHES AND DIAMETER) THIS  
EVENING AS THEY TRACK EAST-SOUTHEASTWARD.  
 
DISCUSSION...A SUPERCELL WHICH DEVELOPED OVER THE BLACK HILLS  
EARLIER THIS AFTERNOON STRENGTHENED AND PRODUCED LARGE HAIL UP TO  
3.5 INCHES IN DIAMETER IN SOUTHWEST SD. SINCE THEN, ADDITIONAL  
SUPERCELLS HAVE DEVELOPED OVER FAR SOUTHEAST MT INTO NORTHWEST SD,  
AND OVER THE BLACK HILLS. THE ENVIRONMENT ACROSS WESTERN SD REMAINS  
QUITE FAVORABLE FOR THE MAINTENANCE FOR INTENSE SUPERCELLS THIS  
EVENING, WITH STRONG INSTABILITY AND DEEP-LAYER SHEAR BOTH PRESENT.  
THESE SUPERCELLS ARE EXPECTED TO GENERALLY TRACK EAST-SOUTHEASTWARD  
WHILE POSING A THREAT FOR MAINLY LARGE TO VERY LARGE HAIL UP TO  
2.5-3.5 INCHES IN DIAMETER. SOME RISK FOR SEVERE/DAMAGING WINDS WILL  
ALSO EXIST WITH RFD SURGES WITH THESE INTENSE CELLS.  
 
..GLEASON.. 08/11/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...UNR...  
 
LAT...LON 45680402 45870388 45830328 45530270 43640213 43130210  
43070322 43610392 44120403 45680402  
 
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH  
MOST PROBABLE PEAK WIND GUST...55-70 MPH  
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN  
 
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