089  
ACUS48 KWNS 170800  
SWOD48  
SPC AC 170759  
 
DAY 4-8 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0259 AM CDT WED SEP 17 2025  
 
VALID 201200Z - 251200Z  
   
..DISCUSSION  
 
MEDIUM-RANGE GUIDANCE GENERALLY INDICATES LOW-AMPLITUDE/WEAK UPPER  
TROUGHING WILL PERSIST ACROSS PORTIONS OF THE CENTRAL U.S. THROUGH  
THE WEEKEND. BY EARLY NEXT WEEK, LARGE SPREAD EXISTS BETWEEN THE  
CONTROL MEMBERS OF THE GFS AND ECMWF AND HOW THESE MODELS HANDLE THE  
EVOLUTION OF A DEEPENING UPPER TROUGH MOVING OUT OF THE ROCKIES AND  
INTO THE PLAINS/MIDWEST AROUND DAYS 6-8/MON-WED. ENSEMBLE MEAN 500  
MB FORECASTS ARE IN BETTER ALIGNMENT, INDICATING A STRONGER  
LARGE-SCALE TROUGH WILL EMERGE OVER THE PLAINS AND MS VALLEY LATE IN  
THE PERIOD, BRINGING A STRONGER AUTUMN COLD FRONT SOUTH/SOUTHEAST  
ACROSS MUCH OF THE CENTRAL U.S. THIS COULD BRING SOME INCREASING  
SEVERE POTENTIAL TO PORTIONS OF THE PLAINS MS VALLEY DURING THE  
SECOND HALF OF THE FORECAST PERIOD, BUT GIVEN AFOREMENTIONED  
UNCERTAINTY/LARGE SPREAD, IT IS UNCLEAR WHICH DAYS/LOCATIONS MAY  
EXPERIENCE ANY INCREASING RISK.  
 
..LEITMAN.. 09/17/2025  
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