April 20: Severe Thunderstorm Watch #3

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 170
   NWS STORM PREDICTION CENTER NORMAN OK
   200 PM CDT WED APR 20 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          ARKANSAS
          FAR SOUTHEAST OKLAHOMA
          FAR NORTHEAST TEXAS
   
   EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 200 PM UNTIL
   900 PM CDT.
   
   HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
   STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES NORTH OF DE
   QUEEN ARKANSAS TO 60 MILES EAST OF LITTLE ROCK ARKANSAS.  FOR A
   COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
   UPDATE (WOUS64 KWNS WOU0).
   
   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 168...WW 169...
   
   DISCUSSION...ELEVATED TSTMS ARE INCREASING IN COVERAGE THIS
   AFTERNOON N OF SYNOPTIC COLD FRONT...LIKELY BEING DRIVEN BY A BAND
   OF ENHANCED ASCENT TIED TO LOW-AMPLITUDE IMPULSE MOVING ACROSS THE
   TX PNHDL AND OK.  GIVEN THE PRESENCE OF STEEP MIDLEVEL LAPSE
   RATES...MUCAPE OF 1000-2000 J/KG AND 40-50+ KT OF EFFECTIVE BULK
   SHEAR...SETUP WILL BE SUPPORTIVE OF SUPERCELLS CAPABLE OF HAIL TO
   THE SIZE OF GOLF BALLS.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
   MOTION VECTOR 27035.