441  
ACUS01 KWNS 041302  
SWODY1  
SPC AC 041300  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0700 AM CST MON DEC 04 2017  
 
VALID 041300Z - 051200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN  
OKLAHOMA AND THE ARK-LA-TEX REGION INTO MISSOURI...  
   
..SUMMARY
 
 
ISOLATED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED ACROSS EASTERN  
OKLAHOMA AND THE ARK-LA-TEX REGION INTO MISSOURI LATE THIS AFTERNOON  
AND EVENING.  
   
..EASTERN OK/ARK-LA-TEX TO MIDDLE MISSISSIPPI VALLEY
 
 
STRONG MID-LEVEL HEIGHT FALLS WILL SPREAD ACROSS THE CENTRAL PLAINS  
TOWARD THE UPPER MIDWEST THROUGH TONIGHT WITH A 90+ KT MID-LEVEL JET  
TRANSLATING ACROSS NORTHERN KS INTO IA/NORTHEAST MO BY EARLY  
EVENING. A SURFACE LOW NEAR THE NE/IA BORDER EARLY THIS EVENING WILL  
DEEPEN AND PROGRESS NORTHEASTWARD, WITH RAPID SURFACE CYCLOGENESIS  
PARTICULARLY OCCURRING TONIGHT FROM THE UPPER MIDWEST INTO NORTHERN  
ONTARIO THROUGH EARLY TUESDAY.  
 
AHEAD OF A COLD FRONT (AND PRE-FRONTAL TROUGH ACROSS THE  
SOUTH-CENTRAL PLAINS), MOISTURE CHARACTERIZED BY UPPER 50S/LOWER 60S  
F SURFACE DEWPOINTS WILL CONTINUE TO GRADUALLY SPREAD  
NORTH-NORTHEASTWARD THROUGH THE DAY. WEAK SURFACE-ROOTED BUOYANCY  
WILL EVOLVE ALONG A PRE-FRONTAL CORRIDOR FROM EASTERN OK INTO MO AND  
SOUTH-CENTRAL IA BY MID/LATE AFTERNOON. WHILE ONLY SEVERAL HUNDRED  
J/KG SBCAPE IS EXPECTED IN MOST AREAS, STRONG LARGE-SCALE FORCING  
FOR ASCENT SUGGESTS CONVECTION WILL INITIATE AND INTENSIFY ALONG THE  
SURGING COLD FRONT BY MID/LATE AFTERNOON.  
 
THE INITIAL DEEPER CONVECTIVE DEVELOPMENT SHOULD OCCUR ACROSS FAR  
EASTERN OKLAHOMA AND SOUTHWEST/CENTRAL MISSOURI AS EARLY AS LATE  
AFTERNOON (ROUGHLY 21Z-23Z). FORECAST SOUNDINGS AND LARGE-SCALE  
FORCING SUGGEST THUNDERSTORMS WILL QUICKLY DEVELOP INTO A SQUALL  
LINE BEFORE ADVANCING INTO CENTRAL MO/WESTERN AR. CONVECTION IS  
EXPECTED TO WEAKEN FARTHER EAST DUE TO LIMITED BUOYANCY AND COOLING  
BOUNDARY LAYER. DAMAGING WINDS ARE THE PRIMARY THREAT ALTHOUGH AT  
LEAST SOME TORNADO RISK MAY EXIST AS WELL GIVEN ADEQUATE MOISTURE  
AND STRONG LOW-LEVEL SHEAR/SRH. PORTIONS OF THE REGION WILL BE  
REEVALUATED IN SUBSEQUENT OUTLOOKS FOR THE POSSIBILITY OF A  
CATEGORICAL SLIGHT RISK PENDING DESTABILIZATION TRENDS.  
   
..UPPER MIDWEST
 
 
A COUPLE OF STRONGER STORMS COULD MATERIALIZE LATE THIS AFTERNOON  
AND EVENING ACROSS PARTS OF WISCONSIN AND/OR WESTERN UPPER MICHIGAN  
IN CONJUNCTION WITH THE STEADILY APPROACHING/DEEPENING CYCLONE AND  
COLD FRONT. STEEPENING MID-LEVEL LAPSE RATES AND MODEST ELEVATED  
BUOYANCY COULD SUPPORT THE POSSIBILITY OF AT LEAST SOME SMALL HAIL  
AND/OR THUNDERSTORM-ENHANCED WIND GUSTS, ALTHOUGH THE POTENTIAL FOR  
SEVERE-CALIBER STORMS CURRENTLY APPEARS LOW.  
 
..GUYER/DIAL.. 12/04/2017  
 

 
 
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