May 25: PDS Tornado Watch #371

URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 371
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT WED MAY 25 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          CENTRAL AND EASTERN ARKANSAS
          MISSOURI BOOTHEEL
          NORTHERN MISSISSIPPI
          WESTERN TENNESSEE
   
   EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL
   1000 PM CDT.
   
   ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
   
   DESTRUCTIVE TORNADOES...LARGE HAIL TO 3 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 85 STATUTE
   MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTHWEST OF LITTLE
   ROCK ARKANSAS TO 50 MILES EAST SOUTHEAST OF JACKSON TENNESSEE. 
   FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
   OUTLINE UPDATE (WOUS64 KWNS WOU1).
   
   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 367...WW 368...WW
   369...WW 370...
   
   DISCUSSION...TSTM INITIATION IS EXPECTED WITHIN THE NEXT ONE TO TWO
   HOURS WITHIN BROADLY CONFLUENT LOW-LEVEL FLOW REGIME IN PLACE ACROSS
   AR.  HERE...AIR MASS IS ALREADY MODERATELY UNSTABLE WITH MLCAPE OF
   2500 J/KG WITH FURTHER DESTABILIZATION EXPECTED THIS AFTERNOON. 
   THIS INSTABILITY AXIS COINCIDES WITH A 60-70 KT MIDLEVEL JET STREAK
   AND 40-50 KT LLJ...RESULTING IN VERY STRONG LOW AND DEEP-LAYER SHEAR
   ACROSS THE BROAD WARM SECTOR.  CURRENT INDICATIONS ARE THAT ONE OR
   MULTIPLE FAST-MOVING BANDS OF SUPERCELLS ARE LIKELY THIS AFTERNOON
   INTO EVENING WITH A THREAT FOR TORNADOES...SOME POTENTIAL STRONG TO
   VIOLENT AND LONG-TRACKED...VERY LARGE HAIL AND DAMAGING WINDS.
   
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
   WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
   500. MEAN STORM MOTION VECTOR 25040.