118  
ACUS11 KWNS 170748  
SWOMCD  
SPC MCD 170747  
SDZ000-NDZ000-170915-  
 
MESOSCALE DISCUSSION 1971  
NWS STORM PREDICTION CENTER NORMAN OK  
0247 AM CDT SUN AUG 17 2025  
 
AREAS AFFECTED...NORTHWEST/NORTH-CENTRAL SD INTO  
SOUTHWEST/SOUTH-CENTRAL ND  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 597...  
 
VALID 170747Z - 170915Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 597  
CONTINUES.  
 
SUMMARY...AN INCREASE IN THE SEVERE-WIND THREAT REMAINS POSSIBLE  
OVERNIGHT.  
 
DISCUSSION...A STORM CLUSTER OVER WESTERN SD HAS SHOWN SIGNS OF  
BECOMING BETTER ORGANIZED OVER THE LAST 30-60 MINUTES, WITH  
INDICATIONS OF BOW-ECHO DEVELOPMENT ACROSS NORTHWEST SD, AND RECENT  
OBSERVED WIND GUSTS OF 50-60 MPH. MUCAPE REMAINS IN THE 2500-4000  
J/KG RANGE, DUE TO STEEP MIDLEVEL LAPSE RATES ATOP A RICHLY MOIST  
BOUNDARY LAYER (AS OBSERVED IN THE 00Z UNR SOUNDING). MEANWHILE,  
BACKED LOW-LEVEL FLOW BENEATH MODEST SOUTHWESTERLIES ALOFT IS  
SUPPORTING EFFECTIVE SHEAR OF 25-35 KT, SUFFICIENT FOR ORGANIZED  
CONVECTION.  
 
A MODEST NOCTURNAL LOW-LEVEL JET COMBINED WITH THE FAVORABLE  
INSTABILITY AND DEEP-LAYER SHEAR WILL SUPPORT CONTINUED  
INTENSIFICATION OF THE ONGOING CLUSTER, AND MAINTENANCE OF THIS  
CLUSTER THROUGH MUCH OF THE OVERNIGHT HOURS. SHORT-TERM GUIDANCE  
SUGGESTS THAT THIS DEVELOPING MCS WILL GENERALLY MOVE NORTHEASTWARD  
ALONG THE MUCAPE AND LOW-LEVEL MOISTURE GRADIENT. THE MAGNITUDE OF  
THE WIND THREAT REMAINS SOMEWHAT UNCERTAIN, DUE TO THE PRESENCE OF  
LOW-LEVEL STABILITY AND SURFACE-BASED CINH. HOWEVER, IF AN ORGANIZED  
MCS DOES PERSIST, SOME INCREASE IN SEVERE-WIND POTENTIAL IS EXPECTED  
OVERNIGHT FROM NORTHERN SD INTO SOUTHERN ND.  
 
..DEAN.. 08/17/2025  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ABR...BIS...UNR...  
 
LAT...LON 45690234 46320209 46540110 46709979 45869933 45339923  
44759944 44280019 44370204 45240186 45690234  
 
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
 
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