May 22- Tornado Watch #326

URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 326
   NWS STORM PREDICTION CENTER NORMAN OK
   150 PM CDT SUN MAY 22 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          CENTRAL OKLAHOMA
          NORTH-CENTRAL TEXAS
   
   EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 150 PM UNTIL 900
   PM CDT.
   
   TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND
   GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
   AREAS.
   
   THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
   MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH NORTHWEST OF
   MCALESTER OKLAHOMA TO 40 MILES SOUTH SOUTHWEST OF MINERAL WELLS
   TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
   WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).
   
   REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
   TORNADOES AND 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.
   
   OTHER WATCH INFORMATION...CONTINUE...WW 321...WW 322...WW
   323...WW 324...WW 325...
   
   DISCUSSION...ISOLATED STORM DEVELOPMENT IS ANTICIPATED ALONG THE
   DRYLINE BY LATE AFTERNOON AS CONTINUED DAYTIME HEATING ERODES
   REMAINING CONVECTIVE INHIBITION.  18Z FWD SOUNDING SHOWED THAT THE
   WARM SECTOR IS ALREADY EXTREMELY UNSTABLE WITH MLCAPE VALUES
   APPROACHING 5000 J/KG.  THIS DEGREE OF INSTABILITY COUPLED WITH
   35-40 KT OF DEEP-LAYER SHEAR WILL SUPPORT INTENSE SUPERCELLS CAPABLE
   OF DESTRUCTIVE HAIL.  THE THREAT FOR TORNADOES WILL INCREASE THIS
   EVENING AS LOW-LEVEL SHEAR INTENSIFIES IN RESPONSE TO THE
   DEVELOPMENT OF A SLY LLJ.
   
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
   WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
   500. MEAN STORM MOTION VECTOR 27020.