SEL9
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 599
   NWS STORM PREDICTION CENTER NORMAN OK
   525 PM CDT SAT JUL 10 2004
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          EASTERN SOUTH DAKOTA
   
   EFFECTIVE THIS SATURDAY AFTERNOON FROM 525 PM UNTIL MIDNIGHT 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 ALONG AND 85 STATUTE MILES
   NORTH AND SOUTH OF A LINE FROM 30 MILES EAST SOUTHEAST OF
   WATERTOWN SOUTH DAKOTA TO 65 MILES NORTHWEST OF CHAMBERLAIN SOUTH
   DAKOTA.
   
   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 596...WW 597...WW 598...
   
   DISCUSSION...CLUSTER OF INTENSE CONVECTION OVER CENTRAL SD WILL
   PROGRESS EASTWARD THROUGH THE EVENING. MOIST/UNSTABLE AIRMASS AND
   INCREASING SOUTHWESTERLY LOW LEVEL JET WILL POSE A RISK OF LARGE
   HAIL AND DAMAGING WINDS ACROSS WW AREA.
   
   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 27030.
   
   
   ...HART