568  
ACUS01 KWNS 031956  
SWODY1  
SPC AC 031955  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0155 PM CST SUN DEC 03 2017  
 
VALID 032000Z - 041200Z  
   
..NO SEVERE THUNDERSTORM AREAS FORECAST
 
 
   
..SUMMARY
 
 
ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF SOUTHEAST TEXAS  
TODAY AND OVER PARTS OF THE UPPER MIDWEST TONIGHT.  
   
..SOUTHEAST TX
 
 
GIVEN TRENDS IN CONVECTIVE DEVELOPMENT AND THE OCCURRENCE OF A  
COUPLE LIGHTNING STRIKES SO FAR ACROSS SOUTHEAST TX, NO CHANGES ARE  
NEEDED IN THE GENERAL THUNDERSTORM AREA. WEAK LAPSE RATES SHOULD  
CONTINUE TO TEMPER UPDRAFT STRENGTH AND SEVERE POTENTIAL, WHILE  
ADDITIONAL CONVECTION/THUNDERSTORMS FORM WITHIN A ZONE OF ASCENT  
ATTENDANT TO A PROGRESSIVE SOUTHERN-STREAM SHORTWAVE TROUGH.  
   
..UPPER MIDWEST
 
 
NO CHANGES NEEDED WITH THIS GENERAL THUNDERSTORM AREA.  
   
..EASTERN ID, WESTERN WY AND ADJACENT SOUTHWEST MT
 
 
LIGHTNING DATA INDICATED A STRIKE IN SOUTHWEST MT ATTENDANT TO  
STRONG FORCING FOR ASCENT, MODIFYING THERMODYNAMIC PROFILES, ALONG  
THE LEADING EDGE OF A PROGRESSIVE MIDLEVEL TROUGH. THE PRESENCE OF  
MEAGER INSTABILITY SUGGESTS ADDITIONAL LIGHTNING SHOULD BE TOO  
SPARSE TO INTRODUCE A GENERAL THUNDERSTORM AREA IN THIS REGION.  
 
..PETERS.. 12/03/2017  
   
PREV DISCUSSION
 
/ISSUED 1022 AM CST SUN DEC 03 2017/  
   
..UPPER MIDWEST LATE TONIGHT
 
 
A WELL-DEFINED MIDLEVEL TROUGH WILL CROSS THE NORTHERN GREAT  
BASIN/ROCKIES AND REACH THE CENTRAL/NORTHERN HIGH PLAINS BY MONDAY  
MORNING. DOWNSTREAM LEE CYCLOGENESIS IS EXPECTED TODAY ACROSS  
EASTERN WY, AND THE CYCLONE WILL PROGRESS EASTWARD ACROSS SD/NE  
OVERNIGHT. THE LEE CYCLOGENESIS WILL INDUCE STRENGTHENING LOW-LEVEL  
SOUTH-SOUTHWESTERLY FLOW AND WARM ADVECTION FROM THE  
SOUTHERN/CENTRAL PLAINS TOWARD THE MID-UPPER MS VALLEY. AFTER ABOUT  
06Z, MOISTENING (E.G., THE 8-10 C 850 MB DEWPOINTS OBSERVED THIS  
MORNING AT FWD AND SGF) AND ASCENT IN THE WARM ADVECTION REGIME  
SHOULD BE SUFFICIENT FOR A FEW ELEVATED THUNDERSTORMS ON THE NOSE OF  
THE LOW-LEVEL JET ACROSS THE UPPER MIDWEST.  
   
..SOUTHEAST TX THIS AFTERNOON/EVENING
 
 
A REMNANT SOUTHERN-STREAM SHORTWAVE TROUGH NEAR THE BIG BEND THIS  
MORNING WILL CONTINUE EASTWARD TO SOUTH CENTRAL TX BY THIS EVENING.  
WEAK ASCENT PRECEDING THIS WAVE, IN CONJUNCTION WITH DAYTIME HEATING  
IN CLOUD BREAKS AND WEAK LOW-LEVEL WARM ADVECTION ON THE  
NORTHEASTERN PERIPHERY OF THE RETURNING MOISTURE (ROUGHLY CLL-HOU),  
SHOULD SUPPORT AT LEAST ISOLATED THUNDERSTORM DEVELOPMENT THIS  
AFTERNOON/EVENING. DEEP-LAYER VERTICAL SHEAR WILL BECOME SUFFICIENT  
FOR STORMS WITH MARGINAL SUPERCELL STRUCTURES NEAR THE MIDDLE TX  
COAST, BUT THE SEVERE STORMS ARE UNLIKELY BASED ON MODEST MIDLEVEL  
LAPSE RATES AND RATHER WEAK LOW-LEVEL SHEAR.  
   
..ELSEWHERE
 
 
VERY ISOLATED LIGHTNING FLASHES CANNOT BE RULED OUT THIS AFTERNOON  
FROM NORTH/NORTHEAST NV TO EASTERN ID AND WESTERN WY. STRONG  
FORCING FOR ASCENT MAY MODIFY PROFILES ENOUGH FOR SOME EMBEDDED  
CONVECTION, BUT VERY MARGINAL BUOYANCY SUGGESTS THAT ANY  
THUNDERSTORM RISK IS TOO LOW TO WARRANT AN OUTLOOK AREA.  
 

 
 
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