MESOSCALE DISCUSSION 0506
   NWS STORM PREDICTION CENTER NORMAN OK
   0730 PM CDT WED APR 17 2013
   
   AREAS AFFECTED...A SMALL PART OF S TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 180030Z - 180200Z
   
   PROBABILITY OF WATCH ISSUANCE...5 PERCENT
   
   SUMMARY...AN ISOLATED SUPERCELL STORM WITH SVR HAIL WILL IMPACT A
   SMALL PART OF S TX DURING THE NEXT HOUR OR TWO. THE VERY ISOLATED
   NATURE OF ANY SVR THREAT WILL PRECLUDE WW ISSUANCE.
   
   DISCUSSION...RICH BOUNDARY-LAYER MOISTURE -- WITH SFC DEWPOINTS
   AROUND 70F -- OVERLAPPING WITH SFC TEMPS IN THE MID 80S BENEATH
   STEEP MID-LEVEL LAPSE RATES WILL CONTINUE SUPPORTING MODERATE
   INSTABILITY DOWNSTREAM OF A SUPERCELL THUNDERSTORM. THIS STORM
   RECENTLY CROSSED THE RIO GRANDE RIVER...MOVING INTO KINNEY COUNTY
   TX...WITH STORM MAINTENANCE/ORGANIZATION SUPPORTED BY OVER 60 KT OF
   EFFECTIVE BULK SHEAR. HOWEVER...A PRONOUNCED CINH LAYER -- EVIDENT
   IN THE CRP/BRO 00Z RAOBS -- WILL LIKELY EVENTUALLY SUPPRESS UPDRAFT
   INTENSITY...ESPECIALLY AS THE BOUNDARY LAYER EXPERIENCES ADDITIONAL
   NOCTURNAL COOLING. REGARDLESS...THE STORM MAY PRODUCE SVR HAIL --
   QUARTER TO PERHAPS GOLF BALL SIZE -- ACROSS SRN KINNEY AND NRN
   MAVERICK COUNTIES BEFORE MOVING EWD/ESEWD INTO ADJACENT UVALDE AND
   ZAVALA COUNTIES DURING THE NEXT HOUR OR TWO.
   
   ..COHEN/THOMPSON.. 04/18/2013
   
   
   ATTN...WFO...EWX...
   
   LAT...LON   28749975 28880054 29250064 29300016 29219933 28899924
               28749975