Day 1 Convective Outlook issued at 1229 UTC 2 March 2012

   SPC AC 021259
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0659 AM CST FRI MAR 02 2012
   
   VALID 021300Z - 031200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR
   EXTREME SRN INDIANA...CENTRAL KY... AND NRN MIDDLE TN...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK...FOR
   MUCH OF THE OH/TN VALLEYS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER MS VALLEY TO THE
   UPPER OH VALLEY AND APPALACHIANS...
   
   --SIGNIFICANT SEVERE WEATHER OUTBREAK EXPECTED THIS AFTERNOON INTO
   TONIGHT ACROSS MUCH OF THE OH/TN VALLEY REGION...INCLUDING THE
   POTENTIAL FOR LONG-TRACK/STRONG TORNADOES--
   
   ...SYNOPSIS...
   A 130 KT JET STREAK ALOFT NOW OVERSPREADING NW OK PER PROFILER PLOTS
   WILL CONTINUE NEWD TO MO/IL/INDIANA BY THIS EVENING.  A COUPLING OF
   LOW-LEVEL WAA/DECREASING STATIC STABILITY AND DIVERGENCE IN THE LEFT
   EXIT REGION OF THE MID-UPPER JET STREAK WILL PROMOTE DEEPENING OF A
   SURFACE CYCLONE WHICH WILL MOVE NEWD FROM MO TO CENTRAL IL BY
   MIDDAY...AND SRN LOWER MI BY THIS EVENING.  A WARM FRONT WILL MOVE
   QUICKLY NWD TODAY IN ADVANCE OF THE CYCLONE...AND A TRAILING COLD
   FRONT WILL SWEEP EWD ACROSS THE MID MS AND OH VALLEY REGION.  A
   RESERVOIR OF L0W-MID 60S BOUNDARY LAYER DEWPOINTS NEAR AND S OF I-40
   WILL SURGE NEWD INTO THE OH VALLEY BY MID-LATE AFTERNOON...WHICH
   WILL CONTRIBUTE TO SUBSTANTIAL NEWD EXPANSION OF THE UNSTABLE WARM
   SECTOR IN THE WAKE OF MORNING ELEVATED CONVECTION IN THE WARM
   ADVECTION REGIME.
   
   ...TN/OH VALLEY REGION TODAY THROUGH THIS EVENING...
   THE INITIAL ELEVATED SEVERE STORMS NEAR STL /JUST AHEAD OF THE
   SURFACE CYCLONE/ WILL CONTINUE TO SPREAD ENEWD OVER CENTRAL
   IL/INDIANA WITH AN ACCOMPANYING RISK FOR LARGE HAIL AND DAMAGING
   GUSTS.  THE MORE SERIOUS SEVERE STORM/TORNADO RISK WILL BEGIN TO
   MATERIALIZE IMMEDIATELY E OF THE MS RIVER BY MIDDAY.  A BROKEN BAND
   OF STORMS WILL LIKELY FORM ALONG THE COLD FRONT BY EARLY
   AFTERNOON...WITH ADDITIONAL STORM DEVELOPMENT EXPECTED FARTHER E IN
   THE UNSTABLE/WEAKLY CAPPED WARM SECTOR.  AS SURFACE TEMPERATURES
   WARM INTO THE UPPER 60S TO MID 70S AND MOISTURE LIKEWISE
   INCREASES...MLCAPE WILL INCREASE TO 1500-2000 J/KG AS FAR NE AS NRN
   KY BY LATE AFTERNOON.  THE DESTABILIZATION WILL BE COINCIDENT WITH
   AN INCREASE IN DEEP-LAYER FLOW/VERTICAL SHEAR...WITH EFFECTIVE BULK
   SHEAR NEAR 70 KT AND EFFECTIVE SRH OF 300-400 M2/S2.  
   
   THE VERY STRONG VERTICAL SHEAR...MODERATE INSTABILITY...A MOIST
   LOW-LEVEL ENVIRONMENT...AND THE LIKELIHOOD OF A FEW DISCRETE WARM
   SECTOR SUPERCELLS / AND SUPERCELLS WITHIN THE LINE ALONG THE
   FRONT/...ALL APPEAR SUPPORTIVE OF A POTENTIALLY SIGNIFICANT TORNADO
   EPISODE WITH A FEW LONG-TRACK/STRONG TORNADOES.  THE MOST PROBABLE
   AREA FOR DAMAGING TORNADOES WILL BE SE OF THE SURFACE LOW TRACK IN
   THE MORE ESTABLISHED WARM SECTOR...OR NEAR AND S OF THE OH RIVER
   FROM EXTREME SRN INDIANA INTO CENTRAL KY/NRN MIDDLE TN.  BOTH
   PRE-FRONTAL AND FRONTAL SUPERCELLS ARE MOST PROBABLE IN THE HIGH
   RISK AREA...AND SOME OF THESE STORMS COULD SPREAD AS FAR NE AS SW OH
   AND WRN WV BEFORE EXITING THE WARM SECTOR THIS EVENING. 
   OTHERWISE...DAMAGING WINDS AND LARGE HAIL CAN ALSO BE EXPECTED WITH
   THE PRE-FRONTAL AND FRONTAL STORMS THROUGH THIS EVENING. 
   
   ...MS/AL/GA LATE THIS AFTERNOON INTO TONIGHT...
   THE MOIST/UNSTABLE WARM SECTOR IS ALREADY ESTABLISHED ACROSS THE
   GULF COAST STATES THIS MORNING.  THIS AREA WILL REMAIN A LITTLE S OF
   THE STRONGEST DEEP-LAYER FLOW...AND THE STRONGEST LLJ CORE WILL
   DEVELOP NEWD TO THE OH VALLEY IN CONJUNCTION WITH THE UPPER JET
   STREAK AND SURFACE CYCLONE.  STILL...INSTABILITY AND VERTICAL SHEAR
   WILL BE FAVORABLE FOR SUPERCELLS WITHIN IN ONE OR MORE BANDS OF
   CONVECTION ALONG AND AHEAD OF THE COLD FRONT BEGINNING LATER THIS
   AFTERNOON AND CONTINUING INTO TONIGHT.  RISKS WILL INCLUDE A FEW
   TORNADOES...DAMAGING WINDS...AND LARGE HAIL THROUGH TONIGHT.
   
   ..THOMPSON/LEITMAN.. 03/02/2012
   
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