MESOSCALE DISCUSSION 0708
   NWS STORM PREDICTION CENTER NORMAN OK
   1221 PM CDT TUE MAY 05 2009
   
   AREAS AFFECTED...SERN OK THROUGH NERN TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 051721Z - 051845Z
   
   THREAT FOR ISOLATED LARGE HAIL AS WELL AS A MORE CONDITIONAL THREAT
   OF ISOLATED DAMAGING WIND MAY INCREASE THIS AFTERNOON. TRENDS ARE
   BEING MONITORED FOR A POSSIBLE WW.
   
   EARLY THIS AFTERNOON A WARM FRONT EXTENDS FROM THE SE U.S. THROUGH
   NRN LA AND NRN TX. SURFACE BASED INSTABILITY REMAINS CONFINED TO
   ALONG AND SOUTH OF THIS BOUNDARY WITH MLCAPE FROM 2000 TO 2500 J/KG
   OVER THE TX WARM SECTOR. HOWEVER...OBSERVATIONAL TRENDS HAVE SHOWN
   THE LEADING EDGE OF STRONGER ELEVATED INSTABILITY ADVANCING NWD TO
   NEAR THE RED RIVER WITH MUCAPE AOA 1000 J/KG ALONG WITH STEEP MID
   LEVEL LAPSE RATES. A SLY LOW LEVEL JET WILL PERSIST OVER N-CNTRL TX
   THIS AFTERNOON DOWNSTREAM FROM A SHORTWAVE TROUGH ADVANCING EWD
   THROUGH THE HIGH PLAINS. INTERSECTION OF LOW LEVEL JET WITH THE
   BAROCLINIC ZONE WILL SUSTAIN A ZONE OF LIFT FROM SERN OK INTO NERN
   TX. IN ADDITION...LOW LEVEL THETA-E ADVECTION WILL LIKELY CONTRIBUTE
   TO DESTABILIZATION A LITTLE FARTHER NWD WITH TIME. WITH TEMPERATURES
   STILL IN THE LOW 60S OVER SRN OK...STORMS REMAIN ELEVATED ABOVE A
   STABLE LAYER. HOWEVER...AS STORMS DEVELOP SEWD WHERE SURFACE
   TEMPERATURES ARE WARMING INTO THE UPPER 60S TO NEAR 70...SUFFICIENT
   DESTABILIZATION OF THE BOUNDARY LAYER MAY OCCUR TO SUPPORT A FORWARD
   PROPAGATING MCS ALONG WITH AN INCREASING  THREAT OF ISOLATED
   DAMAGING WIND.
   
   ..DIAL.. 05/05/2009
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...
   
   LAT...LON   32839510 33399697 34359730 34659595 34129445 32839510