SEL7
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 427
   NWS STORM PREDICTION CENTER NORMAN OK
   405 PM CDT THU JUN 10 2004
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF 
   
          CENTRAL SOUTH DAKOTA
   
   EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 405 PM UNTIL
   900 PM CDT.
   
   TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
   TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES EAST AND WEST
   OF A LINE FROM 60 MILES SOUTH SOUTHWEST OF CHAMBERLAIN SOUTH
   DAKOTA TO 30 MILES NORTH NORTHWEST OF MOBRIDGE SOUTH DAKOTA.
   
   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 424...WW 425...WW 426...
   
   DISCUSSION...THUNDERSTORMS ARE EXPECTED TO CONTINUE DEVELOPING EWD
   ACROSS SD IN RESPONSE TO STRONG DYNAMIC FORCING ASSOCIATED WITH
   VIGOROUS UPPER LEVEL VORTICITY MAX LIFTING ACROSS NRN HIGH PLAINS. 
   AIR MASS IS UNSTABLE WITH MLCAPE TO 1500 J/KG. SUFFICIENT DEEP LAYER
   SHEAR AND LOW LEVEL HELICITY INDICATE POTENTIAL FOR TORNADIC
   SUPERCELLS TO FORM...ESPECIALLY GIVEN THE SELY LOW LEVEL WINDS
   ALONG/NORTH OF THE WARM FRONT ACROSS SRN SD.
   
   AVIATION...TORNADOES AND 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 450.
   MEAN STORM MOTION VECTOR 21035.
   
   
   ...WEISS