Sep 5, 2012 0600 UTC Day 2 Convective Outlook
Updated: Wed Sep 5 06:02:46 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120905 0600 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20120905 0600 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 050600
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT WED SEP 05 2012
   
   VALID 061200Z - 071200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CENTRAL
   AND SRN PLAINS REGION...
   
   ...SYNOPSIS...
   CYCLONIC FLOW ALOFT WILL CONTINUE ACROSS THE NRN HALF OF THE U.S.
   THIS PERIOD...AS THE MAIN UPPER VORTEX OVER CANADA SHIFTS EWD. 
   MEANWHILE...A POTENT SHORT-WAVE TROUGH WILL BEGIN DIGGING SWD INTO
   THE PLAINS ON THE WRN FRINGE OF THIS SYSTEM.
   
   AT THE SURFACE...AN INITIAL COLD FRONT -- MOVING EWD ACROSS THE OH
   VALLEY REGION/LOWER GREAT LAKES AND SEWD INTO THE TN/MID MS/RED
   RIVER VALLEY AREA WILL BE FOLLOWED BY A SECOND/DEVELOPING FRONT
   FORECAST TO SHIFT QUICKLY SWD ACROSS THE PLAINS DURING THE SECOND
   HALF OF THE PERIOD.  BOTH OF THESE BOUNDARIES WILL FOCUS CONVECTION
   AND AT LEAST LIMITED SEVERE THREAT THIS PERIOD.
   
   ...PARTS OF THE CENTRAL AND SRN PLAINS...
   SOMEWHAT COMPLEX FORECAST WITH RESPECT TO CONVECTIVE POTENTIAL
   EXISTS ATTM...AS A BAROCLINIC ZONE -- WHICH WILL HAVE SHIFTED SWD
   INTO THE OZARKS/OK/NWRN TX AT THE START OF THE PERIOD -- WEAKENS
   WITH TIME AS SURFACE PRESSURE FALLS INCREASE FARTHER N IN RESPONSE
   TO THE DIGGING UPPER FEATURE.
   
   AS BOUNDARY LAYER WINDS RESPOND/TURN INCREASINGLY SLY THUS WEAKENING
   THE FRONT...A SECOND FRONT WILL IS PROGGED TO EVOLVE AND BEGIN
   SHIFTING SWD ACROSS THE NRN AND EVENTUALLY THE CENTRAL PLAINS. 
   ATTM...THE NAM SUGGESTS THAT THE CENTRAL PLAINS BOUNDARY LAYER WILL
   NOT FULLY MIX/DESTABILIZE IN THE WAKE OF THE PRIOR FRONTAL
   PASSAGE...SO THERMODYNAMIC QUALITY APPEARS IN QUESTION. 
   STILL...WITH 35 TO 40 KT WNWLY MID-LEVEL FLOW SPREADING ATOP
   LOW-LEVEL SLYS/SELYS...SHEAR SUPPORTIVE OF ORGANIZED STORMS WILL
   EXIST.  OVERALL...SOME THREAT FOR AT LEAST HAIL APPEARS TO EXIST
   FROM ROUGHLY THE RED RIVER VALLEY NWD INTO THE NEB VICINITY...WITH
   WIND ALSO POSSIBLE IF THE BOUNDARY LAYER CAN FULLY MIX/DESTABILIZE. 
   THUS...WILL INTRODUCE SLIGHT RISK INTO THE SRN NEB/KS/OK/TX
   PANHANDLE REGION THIS FORECAST.  WHILE THE MAIN SEVERE THREAT SHOULD
   EXIST IN THE AFTERNOON AND EVENING...STORMS WILL LIKELY CONTINUE
   THROUGH THE OVERNIGHT HOURS AS A SWLY LOW-LEVEL JET SUPPORTS
   CONTINUATION OF CONVECTION. 
   
   ...LOWER GREAT LAKES AND OH/TN/MID MS VALLEY AREAS...
   SHOWERS AND THUNDERSTORMS ARE FORECAST TO INCREASE IN COVERAGE
   THROUGH THE AFTERNOON WITHIN A ZONE FROM THE LOWER GREAT LAKES
   REGION SWWD TO THE MID MS VALLEY AREA...INVOF A SURFACE FRONT
   EXPECTED TO MOVE SLOWLY EWD ACROSS THE REGION.  WHILE POCKETS OF
   MODERATE DESTABILIZATION MAY SUPPORT LOCALLY STRONGER CELLS DURING
   THE AFTERNOON AND EARLY EVENING HOURS...FLOW ALOFT IS FORECAST TO
   REMAIN RELATIVELY MODEST -- LIKELY HINDERING SEVERE POTENTIAL TO
   SOME DEGREE.  STILL...WILL INCLUDE LOW PROBABILITY WIND/HAIL THREAT
   ACROSS THIS REGION -- PRIMARILY THROUGH THE PERIOD OF DIURNAL
   CONVECTIVE MAXIMUM.
   
   ..GOSS.. 09/05/2012
   
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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z