Sep 6, 2012 0100 UTC Day 1 Convective Outlook
Updated: Thu Sep 6 01:01:32 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120906 0100 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120906 0100 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20120906 0100 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20120906 0100 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
   SPC AC 060057
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0757 PM CDT WED SEP 05 2012
   
   VALID 060100Z - 061200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SRN HIGH PLAINS TO WRN
   OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS MID-SOUTH/TN VALLEY
   REGION...
   
   ...SYNOPSIS...
   UPPER-AIR PATTERN IS CHARACTERIZED GENERALLY BY BROADLY CYCLONIC
   FLOW FROM PAC NW TO GREAT LAKES...ASSOCIATED WITH MAJOR VORTEX
   CENTERED IN NERN MB.  STG/EMBEDDED SHORTWAVE TROUGH WAS EVIDENT IN
   MOISTURE CHANNEL IMAGERY OVER SERN BC AND PORTIONS WA....MOVING SEWD
   ACROSS NRN ROCKIES...AND SLATED TO REACH NWRN MT BEFORE END OF
   PERIOD.  FARTHER E...TROUGH AND EMBEDDED VORTICITY MAX WERE EVIDENT
   OVER LS AND ADJOINING ONT LAKEHEAD REGION...NEARLY IN PHASE WITH
   ANOTHER PERTURBATION FROM SRN LOWER MI SWD ACROSS INDIANA TO CENTRAL
   KY.  LATTER FEATURE SHOULD MOVE EWD TOWARD CENTRAL APPALACHIANS AND
   WEAKEN SOMEWHAT...WHILE LS TROUGH EJECTS ENEWD OVER NERN ONT. 
   SEPARATE/CUT-OFF CYCLONE WAS EVIDENT OFFSHORE ATLC COAST OF CENTRAL
   FL.  THIS FEATURE SHOULD DRIFT ERRATICALLY THROUGH 12Z...WHILE
   ANOTHER MID-UPPER LEVEL VORTICITY MAX AND WEAK LOW MOVES SLOWLY SWD
   FROM COASTAL WATERS OF EXTREME SERN LA.
   
   AT SFC...23Z CHART SHOWED WEAK LOW BETWEEN CHI-MKE...WITH COLD FRONT
   SWWD ACROSS SERN CORNER OF IA...MKC AREA...AND NRN TX PANHANDLE.  BY
   12Z...FRONT SHOULD MOVE TO LE...NRN INDIANA...MO OZARKS...WRN OK AND
   TX SOUTH-PLAINS REGION.  SWRN PART OF THIS BOUNDARY MAY BE VERY
   DIFFUSE/ILL-DEFINED WITHIN REMAINS OF OUTFLOW FROM TSTMS NOW OVER
   SRN HIGH PLAINS.
   
   ...SRN HIGH PLAINS TO WRN OK...
   SCATTERED-NUMEROUS MULTICELLULAR TSTMS OVER THIS REGION ARE EXPECTED
   TO CONTINUE POSING RISK FOR STG-SVR OUTFLOW GUSTS FOR ANOTHER FEW
   HOURS INTO WHAT IS LEFT OF WELL-MIXED BOUNDARY LAYER. POTENTIAL
   EXISTS AMIDST GENERALLY WEAK DEEP-LAYER SHEAR AND FAVORABLE BUT
   DIMINISHING BUOYANCY.  REF SPC WWS 622-623 AND RELATED MESOSCALE
   DISCUSSIONS FOR NEAR-TERM GUIDANCE.  LATE THIS EVENING...COMBINATION
   OF DIABATIC SFC COOLING AND EXPANSIVE OUTFLOW COVERAGE WILL RENDER
   AIR MASS PROGRESSIVELY LESS UNSTABLE...AND DIMINISH POTENTIAL FOR
   DAMAGING DOWNDRAFTS TO REACH SFC.
   
   ...MID-SOUTH/TN VALLEY REGION...
   BAND OF STG-SVR TSTMS SHOULD CONTINUE TO MOVE SEWD ACROSS MUCH OF
   SERN KY...TN...AND INTO PORTIONS NRN MS/AL...WITH SPORADIC DAMAGING
   GUSTS THAT GENERALLY WILL BE BELOW 50-KT SVR LIMITS.
   REF SPC WW 621 AND ACCOMPANYING MESOSCALE DISCUSSIONS FOR NOWCAST
   INFORMATION ON THIS SITUATION.  OVERALL SVR POTENTIAL AND CONVECTIVE
   ORGANIZATION EACH IS EXPECTED TO DIMINISH WITH SEWD EXTENT THROUGH
   ABOUT 06Z AS CONVECTION MOVES INTO REGIME CHARACTERIZED BY WEAKENING
   OF BOTH AMBIENT SHEAR AND INSTABILITY.
   
   ...UPPER GREAT LAKES...
   PROBABILITY FOR SFC-BASED SVR CONVECTION WILL CONTINUE TO DIMINISH
   WITH TIME AS COLD FRONT ENCOUNTERS AIR MASS STABILIZED BOTH BY SFC
   COOLING AND BY EARLIER MCS NOW OVER TN.  ELEVATED LOW-LEVEL WAA MAY
   SUPPORT DEVELOPMENT OF SCATTERED TO WIDELY SCATTERED TSTMS E OR SE
   OF PRESENT SFC LOW POSITION...WITH MAIN CONCERN BEING ISOLATED SVR
   HAIL OR STG-/DAMAGING GUSTS...AS ALSO IS TRUE FOR CONVECTION NOW
   MOVING EWD FROM NRN LOWER MI.
   
   ..EDWARDS.. 09/06/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z