MESOSCALE DISCUSSION 0802
   NWS STORM PREDICTION CENTER NORMAN OK
   0220 PM CDT TUE MAY 12 2009
   
   AREAS AFFECTED...EXTREME SERN OK...SRN AR...FAR NRN LA
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 121920Z - 122015Z
   
   THE THREAT FOR DAMAGING WIND GUSTS/LARGE HAIL AS WELL AS HEAVY
   RAINFALL EXISTS MAINLY OVER SRN AR DURING THE NEXT SEVERAL
   HRS...POSSIBLY EXPANDING S INTO NRN LA BY MID TO LATE AFTERNOON.
   UNLESS MCS DEVELOPS INTO ORGANIZED BOW ECHO...WW DOES NOT APPEAR
   NECESSARY.
   
   LEADING EDGE OF MCS WHICH DEVELOPED OVER SERN OK IS CURRENTLY MOVING
   ESE AT AROUND 20 KT INTO SERN-SRN AR. THIS CONVECTIVE SYSTEM IS
   OCCURRING IMMEDIATELY AHEAD OF MID LEVEL RIDGE AXIS...IN AN
   ENVIRONMENT CHARACTERIZED BY STRONGLY VEERING WIND PROFILES
   INDICATIVE OF FAVORABLE WARM AIR ADVECTION REGIME. AT THE
   SURFACE...A WARM FRONT WHICH EXTENDS EWD OUT OF NW TX IS LIFTING NWD
   INTO PORTIONS OF NRN LA. SURFACE TEMPERATURES IN THE 80S RESIDE
   SOUTH OF THE FRONT...WHILE 60S AND 70S ARE LOCATED TO ITS NORTH. IF
   MCS CAN CONTINUE MOVING SE INTO NRN LA...IT WILL BEGIN TO ENCOUNTER
   INCREASING SURFACE BASED INSTABILITY /MLCAPE VALUES AOA 2000 J PER
   KG/. THIS COULD RESULT IN A SSE MOVING FORWARD PROPAGATING BOW
   ECHO...AND A SUBSEQUENT INCREASE IN DAMAGING WIND POTENTIAL.
   
   IN ADDITION TO THE SEVERE WEATHER THREAT...TRAILING PORTION OF MCS
   GUST FRONT EXTENDS W INTO SERN OK...AND IS ROUGHLY ALIGNED PARALLEL
   TO MEAN UPR LVL W-NWLY FLOW. THOUGH SLY LOW LVL INFLOW IS NOT
   PARTICULARLY STRONG...TRAINING STORMS FROM SERN OK INTO SRN AR WILL
   BE POSSIBLE DURING THE NEXT FEW HRS...RESULTING IN POTENTIAL FOR 2-3
   IN/HR RAINFALL RATES.
   
   ..GARNER.. 05/12/2009
   
   
   ATTN...WFO...JAN...LZK...SHV...TSA...
   
   LAT...LON   32759259 32839348 33529403 34129515 34229519 34269250
               33809176 33109197 32759259