MESOSCALE DISCUSSION 0613
   NWS STORM PREDICTION CENTER NORMAN OK
   0329 AM CDT WED APR 27 2011
   
   AREAS AFFECTED...PORTIONS OF NERN TX...NWRN LA...SWRN AR...AND FAR
   SERN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 270829Z - 271030Z
   
   THE THREAT FOR SVR TSTMS...MAINLY ELEVATED WITH A LARGE HAIL
   THREAT...WILL INCREASE INTO THE EARLY MORNING HOURS ACROSS PORTIONS
   OF NERN TX...NWRN LA...SWRN AR...AND FAR SERN OK. A WW IS POSSIBLE.
   
   RECENT WATER VAPOR IMAGERY INDICATES A REGION OF ASCENT LEADING A
   MID-LEVEL COLD CORE THAT IS CURRENTLY SWINGING THROUGH WRN OK. IN
   RESPONSE...CONVECTION /LIKELY ELEVATED/ HAS RECENTLY DEVELOPED
   ACROSS VAN ZANDT AND HENDERSON COUNTIES IN NERN TX. LATEST HIGH-RES
   WRF GUIDANCE SUGGESTS THAT ADDITIONAL CONVECTION WILL INITIATE AS
   THE ASCENT INTERCEPTS STEEP MID-LEVEL LAPSE RATES /AOA 8 C PER KM/
   SUPPORTING MUCAPE VALUES OF 1500 TO 3000 J/KG. WITH EFFECTIVE BULK
   SHEAR MAGNITUDES FROM 40 TO 60 KT...OCCASIONAL MID-LEVEL
   MESOCYCLONES MAY DEVELOP IN ASSOCIATION WITH DEEPER UPDRAFTS...
   ENHANCING THE THREAT FOR LARGE HAIL. WHILE CONVECTION WILL LIKELY BE
   ROOTED ABOVE THE SFC...THE THREAT FOR DAMAGING WINDS CANNOT BE
   ENTIRELY RULED OUT IF MERGING COLD POOLS RESULT IN UPSCALE GROWTH
   SOUTHEAST OF A FRONT DRAPED NE TO SW ACROSS THE ARKLATEX REGION.
   HOWEVER...OVERTURNING DUE TO EARLIER CONVECTION IN THIS REGION WILL
   MITIGATE THIS POTENTIAL TO SOME DEGREE.
   
   ..COHEN.. 04/27/2011
   
   
   ATTN...WFO...SHV...FWD...
   
   LAT...LON   32209676 32859658 33589594 34019493 33809365 33039314
               32109379 31619495 31669635 32209676