716  
ACUS01 KWNS 271959  
SWODY1  
SPC AC 271957  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0257 PM CDT SUN SEP 27 2026  
 
VALID 272000Z - 281200Z  
   
..NO SEVERE THUNDERSTORM AREAS FORECAST
 
 
   
..SUMMARY
 
 
ORGANIZED SEVERE STORMS ARE NOT EXPECTED THROUGH EARLY MONDAY.  
   
..20Z UPDATE
 
 
NO CHANGES WERE MADE TO THE EXISTING OUTLOOK WITH THIS UPDATE CYCLE.  
ISOLATED CONVECTIVE DEVELOPMENT IS ONGOING ACROSS PORTIONS OF  
CENTRAL/NORTH TEXAS AS OF 1945 UTC. WHILE AN ISOLATED  
STRONG/DAMAGING WIND GUST CANNOT BE RULED OUT WITH THIS ACTIVITY  
OWING TO STEEP LOW-LEVEL LAPSE RATES AND MODERATE BUOYANCY, WEAK  
LOWER TROPOSPHERIC FLOW (AS DEPICTED BY REGIONAL VWPS), LIMITED  
EFFECTIVE SHEAR, AND POOR MID-LEVEL LAPSE RATES SHOULD LARGELY  
TEMPER OVERALL CONVECTIVE INTENSITY. THUS, THE SEVERE THREAT  
CONTINUES TO APPEAR TOO LOW (LESS THAN 5%) TO WARRANT THE INCLUSION  
OF SEVERE PROBABILITIES. SEE THE DISCUSSION BELOW FOR ADDITIONAL  
DETAILS.  
 
..CHALMERS/GUYER.. 09/27/2026  
   
PREV DISCUSSION
 
/ISSUED 1137 AM CDT SUN SEP 27 2026/  
   
..SYNOPSIS
 
 
AN OCCLUDED CYCLONE WILL SLOWLY WEAKEN NEAR THE NORTHERN  
MID-ATLANTIC COAST, WITH LINGERING POTENTIAL FOR ELEVATED CONVECTION  
AND ISOLATED LIGHTNING FLASHES TO ITS NORTHEAST ACROSS SOUTHEAST NEW  
ENGLAND. FARTHER WEST, WEAK RIDGING ALOFT WILL EXTEND FROM THE  
SOUTHERN HIGH PLAINS TOWARD MN. A FEW THUNDERSTORMS WILL BE  
POSSIBLE LATE THIS AFTERNOON/EVENING ALONG A DIFFUSE SURFACE  
BOUNDARY FROM NORTH TX INTO SOUTHERN OK. THE STRONGEST STORMS MAY  
PRODUCE GUSTY OUTFLOW WINDS GIVEN STEEP LOW-LEVEL LAPSE RATES WITH  
AFTERNOON MIXING, BUT THE SEVERE THREAT APPEARS TOO LOW TO JUSTIFY  
ADDING SEVERE-WIND PROBABILITIES.  
 
SLIGHTLY ELEVATED CONVECTION IS ONGOING ACROSS CENTRAL SD IN A ZONE  
OF WEAK LOW-LEVEL FRONTOGENESIS, COINCIDENT WITH MIDLEVEL LAPSE  
RATES NEAR 8 C/KM AND MUCAPE CLOSE TO 1000 J/KG. DEEP-LAYER  
VERTICAL SHEAR IS ON THE LOWER MARGINS FOR STORM ORGANIZATION, BUT  
IT APPEARS THIS CONVECTION HAS ALREADY PEAKED. ADDITIONAL ELEVATED  
THUNDERSTORMS ARE EXPECTED OVERNIGHT FROM WESTERN SD INTO ND AS  
LOW-LEVEL WARM ADVECTION INCREASES IN ASSOCIATION WITH EMBEDDED  
SPEED MAXIMA DOWNSTREAM FROM A MIDLEVEL TROUGH MOVING ACROSS CA/NV.  
WHILE AN ISOLATED HAIL REPORT COULD OCCUR OVERNIGHT AS FAR NORTHEAST  
AS SOUTHWEST ND, THE OVERALL THREAT IS LOW AND WHEN COMBINED WITH  
THE QUESTIONABLE THREAT FOR DIURNAL CONVECTION ACROSS THE CENTRAL  
HIGH PLAINS, THE MRGL AREA HAS BEEN REMOVED.  
 

 
 
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