Sep 30, 2009 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Wed Sep 30 07:32:45 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20090930 0730 UTC Day 3 Outlook Graphic
Probabilistic Graphic
20090930 0730 UTC Day Probabilitic Graphic
Probability Legend Image
   SPC AC 300729
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0229 AM CDT WED SEP 30 2009
   
   VALID 021200Z - 031200Z
   
   ...SYNOPSIS...
   A STRONG UPPER LOW WILL CONTINUE MOVING SLOWLY EWD ACROSS THE
   CENTRAL U.S. THIS PERIOD...WITH AN ASSOCIATED COLD FRONT PROGGED TO
   MOVE EWD ACROSS THE ERN THIRD OF THE CONUS AND APPROACH THE
   APPALACHIANS LATE.  THIS FRONT SHOULD AGAIN SERVE AS A FOCUS FOR
   RELATIVELY WIDESPREAD CONVECTION...AND ASSOCIATED/LIMITED SEVERE
   POTENTIAL.
   
   ...COASTAL CAROLINAS WSWWD ACROSS THE GULF COAST REGION...
   SHOWERS AND THUNDERSTORMS WILL BE ONGOING AT THE START OF THE PERIOD
   -- LIKELY ACROSS PORTIONS OF THE CENTRAL GULF COAST STATES/TN VALLEY
   REGION ALONG A COLD FRONT MOVING INTO THIS REGION.  THE FRONT IS
   FORECAST TO MAKE STEADY EWD/SEWD PROGRESS THROUGH THE AFTERNOON...AS
   SOME DIURNAL DESTABILIZATION OF THE PRE-FRONTAL AIRMASS OCCURS
   DESPITE ONGOING PRECIPITATION/CLOUD COVER.
   
   THE DEGREE OF DESTABILIZATION SHOULD BE SUFFICIENT TO SUPPORT AN
   AFTERNOON INCREASE IN CONVECTIVE COVERAGE/INTENSITY -- AIDED BY
   MODERATE DEEP-LAYER SHEAR.  HOWEVER...THE OVERALL SHEAR/INSTABILITY
   COMBINATION APPEARS ATTM TO SUPPORT ONLY ISOLATED SEVERE STORMS --
   PARTICULARLY WITH STRONGER FORCING ALOFT TO REMAIN WELL N OF THIS
   REGION.  THUS...WILL INTRODUCE ONLY 5% SEVERE PROBABILITY THIS
   FORECAST.
   
   ..GOSS.. 09/30/2009
   
   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z