SEVERE THUNDERSTORM WATCH NUMBER 185

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 185
   NWS STORM PREDICTION CENTER NORMAN OK
   230 PM CDT FRI APR 20 2012
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          DEEP SOUTH TEXAS
          COASTAL WATERS
   
   EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 230 PM UNTIL
   1000 PM CDT.
   
   HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
   STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES SOUTH OF
   MCALLEN TEXAS TO 30 MILES NORTH NORTHWEST OF ALICE TEXAS.  FOR A
   COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
   UPDATE (WOUS64 KWNS WOU5).
   
   REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
   FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
   DO PRODUCE TORNADOES.
   
   OTHER WATCH INFORMATION...CONTINUE...WW 184...
   
   DISCUSSION...SVR TSTMS EXPECTED TO DEVELOP ALONG AND POSSIBLY AHEAD
   OF SFC COLD FRONT IN ENVIRONMENT CHARACTERIZED BY 2000-3000 J/KG
   MLCAPE AND 40-50 KT EFFECTIVE SHEAR MAGNITUDES. SUPERCELLS AND
   COLD-POOL DRIVEN CLUSTERS EACH ARE POSSIBLE...OFFERING
   LARGE/DAMAGING HAIL AND RISK FOR SVR GUSTS.  TORNADO CANNOT BE RULED
   OUT...BUT WITH WEAK AMBIENT/EFFECTIVE SRH OVER AREA...RISK IS VERY
   DEPENDENT ON STORM-SCALE PROCESSES.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
   MOTION VECTOR 30025.