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   URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 660
   NWS STORM PREDICTION CENTER NORMAN OK
   900 PM CDT TUE JUL 20 2004
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          SOUTHWEST MINNESOTA
          NORTHERN AND EASTERN SOUTH DAKOTA
   
   EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 900 PM
   UNTIL 100 AM CDT.
   
   HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
   
   THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 65 STATUTE MILES
   EITHER SIDE OF A LINE FROM 20 MILES SOUTHEAST OF REDWOOD FALLS
   MINNESOTA TO 80 MILES WEST OF ABERDEEN 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 657...WW 658...
   
   DISCUSSION...THUNDERSTORM CLUSTER NOW NEAR BKX EXPECTED TO
   MOVE/DEVELOP E/NE INTO SW MN DURING THE NEXT 1-2 HRS.  FARTHER
   NW...STORMS NOW E AND NE OF MBG EXPECTED TO MERGE INTO A CLUSTER
   THAT SHOULD MOVE/DEVELOP SE TOWARD ABR/HON LATER THIS EVENING. 
   WHILE INCREASING CIN SHOULD RESULT IN A GRADUAL DECREASE IN
   INTENSITY LATER TONIGHT...MODEST STRENGTHENING OF LOW LEVEL JET AND
   PRESENCE OF EXISTING STORMS SUGGESTS A CONTINUED THREAT FOR SEVERE
   BEYOND SCHEDULED EXPIRATION OF WW 657.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
   MOTION VECTOR 27020.
   
   
   ...CORFIDI