MESOSCALE DISCUSSION 0688
   NWS STORM PREDICTION CENTER NORMAN OK
   1255 AM CDT MON MAY 02 2011
   
   AREAS AFFECTED...PORTIONS CENTRAL AND NRN TX...SERN OK.
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 020555Z - 020830Z
   
   TSTM COVERAGE IS INCREASING OVER REGION...WITH OCNL LARGE HAIL
   POSSIBLE. WHILE STG GUST CANNOT BE RULED OUT...THREAT IS MUCH LOWER
   THAN PREVIOUS NIGHT DUE TO DEEPER AND MORE STABLE STRATIFICATION OF
   SUBFRONTAL LAYER.
   
   AS OF 05Z...SFC COLD FRONT WAS ANALYZED FROM NWRN TN SWWD ACROSS
   MID-UPPER TX COASTAL PLAIN...TO BETWEEN COT-LRD.  850-MB COLD FRONT
   POSITION WAS ESTIMATED FROM AR OZARKS SWWD NEAR
   DEQ...ACT...JCT...USING BLEND OF 00Z UPPER-AIR ANALYSES...LATEST
   VWP/PROFILER WINDS...AND RUC FCSTS.  BULK OF ISENTROPIC ASCENT TO
   LFC WILL REMAIN ALONG AND N OF 850-MB FRONT ON NOSE OF WRN BRANCH OF
   LLJ.  FRONTAL LAYER APPEARED TO BE ABOUT 1.5 KM THICK AGL AT FTW AND
   2 KM DEEP ABOVE DYS...BASED ON VWP...WITH MODIFIED FWD RAOB AND RUC
   SOUNDINGS EACH DEPICTING NEAR-SATURATION OF AIR MASS BELOW FRONTAL
   SFC EXCEPT FOR THIN/NEAR-SFC SKIN LAYER.  WHILE LAPSE RATES HAVE
   DIMINISHED SOMEWHAT ABOVE FRONTAL LAYER DURING PAST 18-24
   HOURS...BUOYANCY AIDED BY ELEVATED THETAE ADVECTION SHOULD BE
   SUFFICIENT TO SUPPORT ADDITIONAL CONVECTIVE DEVELOPMENT.  FWD RAOB
   CONTAINED WET-BULBING ANOMALIES...HOWEVER STILL YIELDS ABOUT
   1500-1800 J/KG MUCAPE WHEN MODIFYING THOSE ARTIFACTS AWAY. 
   FAVORABLE DEEP-LAYER SHEAR WILL PERSIST TO SUPPORT ELEVATED
   SUPERCELLS...WITH 45-55 KT EFFECTIVE SHEAR MAGNITUDES.  WRN LLJ
   BRANCH IS FCST TO VEER/WEAKEN AFTER ABOUT 08Z...AFTER WHICH
   CONVECTIVE POTENTIAL SHOULD PERSIST AND SHIFT NEWD...BUT SVR THREAT
   SHOULD DIMINISH.
   
   ..EDWARDS.. 05/02/2011
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...EWX...SJT...
   
   LAT...LON   30929836 30649928 30849998 31170054 32090047 32899919
               33779710 34229595 34179523 34059499 33459489 32219587
               31259749 30929836