002  
ACUS01 KWNS 290050  
SWODY1  
SPC AC 290049  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0749 PM CDT SAT JUN 28 2025  
 
VALID 290100Z - 291200Z  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER  
MIDWEST INTO THE NORTHERN HIGH PLAINS...  
   
..SUMMARY  
 
SCATTERED SEVERE THUNDERSTORMS WILL SPREAD ACROSS THE UPPER MIDWEST  
AND PORTIONS OF THE NORTHERN PLAINS THIS EVENING INTO THE OVERNIGHT  
HOURS. ALL SEVERE HAZARDS ARE POSSIBLE.  
   
..01Z UPDATE  
 
SHORT-WAVE RIDGING HAS FLATTENED ACROSS THE NORTHERN PLAINS/UPPER  
MIDWEST AS BROADER CYCLONIC FLOW NOW EXTENDS ACROSS THE NORTHERN  
ROCKIES INTO THE EASTERN DAKOTAS. THIS FLOW REGIME IS NOTABLY  
DIFFLUENT ACROSS THE UPPER MIDWEST, AND SCATTERED DEEP CONVECTION IS  
MATURING WITHIN THIS FAVORABLE ENVIRONMENT FROM THE UPPER RED RIVER  
VALLEY INTO SOUTHWESTERN MN. WHILE LLJ IS NOT PARTICULARLY STRONG AT  
THIS TIME, LATEST MODEL GUIDANCE SUGGESTS 1KM FLOW COULD INCREASE IN  
EXCESS OF 35KT ACROSS SOUTHERN MN BY MID-LATE EVENING. SCATTERED  
SUPERCELLS HAVE EVOLVED NEAR THE SD/MN BORDER, AND THIS ACTIVITY  
COULD GROW UPSCALE AS IT PROPAGATES DOWNSTREAM ALONG A WEAK  
BOUNDARY, AIDED BY THE AFOREMENTIONED INCREASE IN LLJ AND ASSOCIATED  
LOW-LEVEL WARM ADVECTION. 00Z SOUNDING FROM ABR EXHIBITED MLCAPE  
AROUND 3000 J/KG WITH ADEQUATE DEEP-LAYER SHEAR FOR SUSTAINING  
ORGANIZED UPDRAFTS. THIS SUPPORTS THE POTENTIAL FOR ALL HAZARDS WITH  
THESE STORMS INTO THE LATE-EVENING HOURS.  
 
UPSTREAM ACROSS THE HIGH PLAINS, WATER-VAPOR IMAGERY SUGGESTS A WEAK  
DISTURBANCE IS EJECTING ACROSS SOUTHERN MT, AND THIS FEATURE WILL  
SHIFT INTO THE WESTERN DAKOTAS BY THE END OF THE PERIOD. ISOLATED  
THUNDERSTORMS DEVELOPED OVER THE HIGHER TERRAIN SOUTHWEST OF  
BILLINGS MT, AND THERE IS SOME CONCERN FOR ADDITIONAL DEVELOPMENT  
AHEAD OF THE SHORT WAVE LATER TONIGHT AS IT ENCOUNTERS A BIT MORE  
MOISTURE/INSTABILITY OVER SOUTHEAST MT INTO THE BLACK HILLS REGION.  
UNTIL THEN, A LONG-LIVED SUPERCELL IS DIGGING SOUTHEAST ACROSS  
JACKSON COUNTY SD, JUST SOUTH OF PHILLIP. THIS STORM HAS A HISTORY  
OF PRODUCING VERY LARGE HAIL AND DAMAGING WINDS. THIS ACTIVITY MAY  
REMAIN SOMEWHAT ISOLATED AS IT PROPAGATES TOWARD SOUTH CENTRAL SD  
LATER THIS EVENING.  
 
..DARROW.. 06/29/2025  
 
 
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