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000 

WWUS20 KWNS 060231

SEL0

SPC WW 060231

IAZ000-MNZ000-NEZ000-SDZ000-060900-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 240

NWS STORM PREDICTION CENTER NORMAN OK

930 PM CDT SAT MAY 5 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN IOWA

       SOUTHWEST MINNESOTA

       CENTRAL AND EASTERN NEBRASKA

       SOUTHERN AND EASTERN SOUTH DAKOTA



EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 930 PM

UNTIL 400 AM CDT.



TORNADOES...HAIL TO 1.5 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 110 STATUTE

MILES EAST AND WEST OF A LINE FROM 10 MILES NORTHEAST OF HURON

SOUTH DAKOTA TO 55 MILES SOUTHEAST OF HASTINGS NEBRASKA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU0).



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 232...TORNADO WATCH NUMBER 235. WATCH NUMBER 232 235

WILL NOT BE IN EFFECT AFTER 930 PM CDT. CONTINUE...WW 234...WW

236...WW 237...WW 238...WW 239...



DISCUSSION...SCATTERED STORMS/SUPERCELLS EXPECTED TO MOVE/DEVELOP

NNE ACROSS WW AREA...BOTH ALONG NOSE OF CONFLUENT LLJ AND INVOF DRY

LINE/LEE TROUGH IN WRN PART OF WW.  DESPITE WEAKENING SFC-BASED

INSTABILITY... ENVIRONMENT MAY SUPPORT ADDITIONAL TORNADOES AS WELL

AS HAIL/HIGH WIND.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 21045.





...CORFIDI

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