SEL4
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 814
   NWS STORM PREDICTION CENTER NORMAN OK
   1250 PM EDT WED SEP 8 2004
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          DISTRICT OF COLUMBIA
          SOUTHERN MARYLAND
          CENTRAL AND EASTERN NORTH CAROLINA
          CENTRAL AND EASTERN VIRGINIA
          COASTAL WATERS
   
   EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL
   700 PM EDT.
   
   TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
   TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE TORNADO WATCH AREA IS ALONG AND 80 STATUTE MILES EAST AND WEST
   OF A LINE FROM 55 MILES NORTH NORTHEAST OF CHARLOTTESVILLE
   VIRGINIA TO 15 MILES SOUTHEAST OF FAYETTEVILLE NORTH CAROLINA.
   
   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...THIS TORNADO WATCH REPLACES TORNADO
   WATCH NUMBER 813. WATCH NUMBER 813 WILL NOT BE IN EFFECT AFTER
   1250 PM EDT. 
   
   DISCUSSION...BREAKS IN CLOUDS WILL CONTINUE TO SPREAD NWD ACROSS
   VA...ALLOWING ADDITIONAL DESTABILIZATION THIS AFTERNOON.  BOUNDARY
   LAYER DEWPOINTS IN THE MID 70S AND TEMPERATURES IN THE 80S WILL
   SUPPORT SBCAPE VALUES OF 1500-2500 J/KG...IN AN ENVIRONMENT OF 0-1
   KM SRH OF 200-300 M2/S2.  THE THREAT FOR SUPERCELLS WITH A FEW
   TORNADOES WILL LIKELY INCREASE THIS AFTERNOON AS CELLULAR CONVECTION
   INCREASES IN THE WARM SECTOR FROM CENTRAL NC TO CENTRAL VA...WITH
   THE GREATEST TORNADO THREAT FOCUSED ALONG A WEAK BAROCLINIC ZONE
   ACROSS CENTRAL VA.
   
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND
   GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
   MEAN STORM MOTION VECTOR 18025.
   
   
   ...THOMPSON