MESOSCALE DISCUSSION 0704
   NWS STORM PREDICTION CENTER NORMAN OK
   0423 PM CDT MON MAY 09 2011
   
   AREAS AFFECTED...PORTIONS OF CNTRL TX INTO SWRN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 092123Z - 092330Z
   
   AN ISOLATED SVR STORM OR TWO COULD DEVELOP ACROSS PORTIONS OF CNTRL
   TX INTO SWRN OK LATER THIS AFTERNOON. GIVEN THE ANTICIPATED SPARSE
   COVERAGE OF ANY SVR STORMS...THE ISSUANCE OF A WW IS UNLIKELY.
   
   MID-AFTERNOON SFC ANALYSIS DEPICTS A DRYLINE EXTENDING FROM 20 NNE
   CSM TO THE RED RIVER 20 SSW LTS TO 45 NNW ABI AND FARTHER SSW TO 55
   WSW SJT. STRONG INSOLATION OVER THE ERN PERIPHERY OF A THERMAL AXIS
   /LOCATED WEST OF THE DRYLINE/ HAS RESULTED IN TEMPERATURES WARMING
   INTO THE UPPER 90S TO 103 DEGREES. MODIFIED 12Z OBSERVED SOUNDINGS
   AND RAPID REFRESH FORECAST SOUNDINGS SUGGEST THAT THE STRONG
   DIABATIC HEATING HAS SUBSTANTIALLY REDUCED SURFACE-BASED CINH WITHIN
   A NARROW CORRIDOR ALONG AND JUST EAST OF THE DRYLINE. THE REDUCTION
   IN CINH...ALONG WITH LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE
   DRYLINE...HAS LED TO THE INITIATION OF A FEW HIGHER-BASED CU WEST OF
   THE DRYLINE. THIS INITIAL ATTEMPT AT CONVECTION MAY ALSO BE
   SUPPORTED BY A SUBTLE MID-LEVEL WAVE EMERGING FROM THE HIGHER
   TERRAIN OF NRN MEXICO INTO TX...ALSO RESPONSIBLE FOR HIGH-LEVEL
   CLOUDINESS OVER THE MOIST SECTOR.
   
   RECENT RUNS OF THE EXPERIMENTAL HRRR SUGGEST SOME POTENTIAL FOR ONE
   OR TWO DEEPER CONVECTIVE PLUMES TO EMANATE FROM THE CU FIELD AS
   HEATING CONTINUES AND THE BOUNDARY LAYER DEEPENS. ANY INCIPIENT
   CONVECTION WILL BE HIGH BASED...WITH THE POTENTIAL FOR SUPERCELLULAR
   STRUCTURES TO EVOLVE GIVEN EFFECTIVE BULK SHEAR MAGNITUDES OF 35-45
   KT. THE THREAT FOR LARGE HAIL WILL EXIST PROVIDED VERY STEEP
   MID-LEVEL LAPSE RATES /IN EXCESS OF 8.5 C PER KM/ ASSOCIATED WITH A
   STRONG ELEVATED MIXED LAYER. STEEP LOW-LEVEL LAPSE RATES...IN PART
   YIELDING DCAPE VALUES AOA 1300 J PER KG...SUGGESTS A POTENTIAL FOR
   DMGG WINDS...AS WELL. THE THREAT FOR VERY LARGE HAIL /ALBEIT A LOW
   THREAT/ MAY OCCUR IF CONVECTION CAN SUSTAIN ITSELF EAST OF THE
   DRYLINE AND TRAVERSE RICHER LOW-LEVEL MOISTURE AND A VERY UNSTABLE
   AIR MASS -- I.E. SFC DEWPOINTS AOA THE MIDDLE 60S SUPPORTING MLCAPE
   VALUES OVER 3500 J/KG. HIGH LCL HEIGHTS AND RELATIVELY WEAK
   LOW-LEVEL FLOW WILL MITIGATE THE THREAT FOR ANY TORNADOES. WITH THE
   ONLY SUBSTANTIAL FORCING FOR CONVECTION EXPECTED TO BE MAINLY TIED
   TO THE DRYLINE...AND GIVEN THE STRONG CINH AWAY FROM THE
   DRYLINE...ANY SEVERE CONVECTIVE COVERAGE IS EXPECTED TO BE SPARSE.
   
   ..COHEN.. 05/09/2011
   
   
   ATTN...WFO...FWD...OUN...EWX...SJT...LUB...MAF...
   
   LAT...LON   35299809 35269863 34429895 33809935 33169985 32350060
               31830081 30980046 30569972 30529905 31019828 31779778
               32459746 33759750 34949751 35299809