MESOSCALE DISCUSSION 0656
   NWS STORM PREDICTION CENTER NORMAN OK
   0248 PM CDT FRI MAY 01 2009
   
   AREAS AFFECTED...NWRN TX...SRN OK
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 011948Z - 012115Z
   
   ...TORNADO WATCH WILL LIKELY BE ISSUED BY 21Z FOR PORTIONS OF NWRN
   TX AND SRN OK...
   
   LATEST SFC ANALYSIS INDICATES STRONG BOUNDARY LAYER HEATING HAS ALL
   BUT REMOVED WHAT LITTLE INHIBITION EXISTED ALONG DRYLINE/COLD FRONT
   ACROSS NWRN TX.  AS A RESULT...CU FIELD IS BEGINNING TO
   EXPAND/DEEPEN ACROSS THIS REGION...PRIMARILY WHERE SFC TEMPERATURES
   HAVE WARMED INTO THE LOWER 90S BETWEEN CDS-ABI...JUST SOUTH OF THE
   SFC FRONT.  ALTHOUGH DEEP LAYER SHEAR IS SOMEWHAT MARGINAL...SFC-6KM
   VALUES ON THE ORDER OF 30KT...INSTABILITY IS BECOMING QUITE
   IMPRESSIVE AS LAPSE RATES STEEPEN IN EXCESS OF 8 C/KM...YIELDING
   MLCAPE VALUES ON THE ORDER OF 4500 J/KG.  IT APPEARS THUNDERSTORMS
   WILL EVOLVE IN THE NEXT FEW HOURS ALONG ADVANCING COLD FRONT/DRYLINE
   WITH SUBSEQUENT SLOW SEWD EXPANSION EXPECTED ACROSS NWRN TX/SRN OK. 
   WITH DEW POINTS NOW WELL INTO THE UPPER 60S IT APPEARS THERMODYNAMIC
   PROFILES WILL COMPENSATE FOR WEAKER SHEAR AND SUPPORT AT LEAST A
   RISK FOR TORNADOES WITH SLOW-MOVING HP SUPERCELLS.
   
   ..DARROW.. 05/01/2009
   
   
   ATTN...WFO...FWD...OUN...SJT...LUB...
   
   LAT...LON   33300061 34389847 34609709 33619676 32619824 32140030
               33300061