May 11, 2010 1300 UTC Day 1 Convective Outlook
Updated: Tue May 11 12:26:17 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20100511 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20100511 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20100511 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20100511 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 111223
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0723 AM CDT TUE MAY 11 2010
   
   VALID 111300Z - 121200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT FOR
   OK/KS EWD TO NRN AR AND MO...
   
   ...SYNOPSIS...
   AN INITIAL MIDLEVEL SHORTWAVE TROUGH OVER THE OH VALLEY WILL
   CONTINUE TO DECAY AND MOVE EWD TO PA/NY AS LARGE SCALE HEIGHT RISES
   OCCUR OVER THE MS VALLEY.  UPSTREAM...A HIGH-AMPLITUDE TROUGH/CLOSED
   LOW WILL PROGRESS EWD FROM THE GREAT BASIN TO THE CENTRAL ROCKIES. 
   THE APPROACH OF THE GREAT BASIN TROUGH WILL INDUCE LEE CYCLOGENESIS
   ACROSS THE SRN HIGH PLAINS AND STRENGTHENING LOW-LEVEL SLY FLOW
   FARTHER E ACROSS TX/OK/KS.  THIS WILL ALLOW THE STALLED FRONT ALONG
   I-44 IN OK TO MOVE NWD AS A WARM FRONT THIS AFTERNOON INTO TONIGHT.
   
   ...OH VALLEY TO SRN PLAINS THROUGH TONIGHT...
   ASIDE FROM THE ELEVATED CONVECTION MOVING EWD OVER WRN OH...
   THUNDERSTORM COVERAGE SHOULD REMAIN ISOLATED THIS AFTERNOON/EVENING
   ALONG THE OH VALLEY PORTION OF THE FRONT.  ASCENT WILL DIMINISH AS
   THE MIDLEVEL WAVE MOVES BY EARLY IN THE DAY...LEAVING A NARROW
   CORRIDOR OF MOISTENING/DESTABILIZATION ALONG THE STALLING FRONT THIS
   AFTERNOON.  STORMS THAT FORM ALONG THE FRONT COULD DEVELOP SUPERCELL
   STRUCTURES GIVEN 0-6 KM BULK SHEAR NEAR 50 KT...BUT WEAK INSTABILITY
   WITH NEWD EXTENT FROM THE LOWER OH VALLEY WILL LIMIT THE OVERALL
   HAIL/WIND THREAT.  
   
   STRONGER SURFACE-BASED INSTABILITY IS EXPECTED ALONG AND S OF THE
   FRONT FROM SRN MO/AR INTO CENTRAL/SRN OK...WITH MLCAPE OF 3000-4000
   J/KG EXPECTED ACROSS OK WHERE NEAR 70 F BOUNDARY LAYER DEWPOINTS LIE
   BENEATH 7-8 C/KM MIDLEVEL LAPSE RATES.  THUNDERSTORM COVERAGE ACROSS
   OK/AR/MO DURING THE AFTERNOON IS IN QUESTION GIVEN MINIMAL LARGE
   SCALE SUPPORT FOR ASCENT AND A RATHER STRONG CAP.  IF STORMS DO FORM
   ALONG THE FRONT AND/OR DRYLINE THIS AFTERNOON...THE ENVIRONMENT WILL
   BE FAVORABLE FOR SUPERCELLS WITH A MORE SUBSTANTIAL HAIL/TORNADO
   THREAT THAN INDICATED BY THE UNCONDITIONAL PROBABILITIES.  THE MORE
   PROBABLE SCENARIO IS FOR ELEVATED CONVECTION TO FORM TONIGHT AS THE
   LLJ AND WAA STRENGTHEN FROM NRN OK INTO KS/MO...WHERE ELEVATED
   INSTABILITY AND EFFECTIVE BULK SHEAR WILL BE SUFFICIENT FOR
   ORGANIZED CLUSTERS/SUPERCELLS WITH VERY LARGE HAIL...AND ISOLATED
   DAMAGING WIND.
   
   ..THOMPSON/HURLBUT.. 05/11/2010
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z