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878 

WWUS20 KWNS 210300

SEL2

SPC WW 210300

IAZ000-MNZ000-NEZ000-SDZ000-211000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 362

NWS STORM PREDICTION CENTER NORMAN OK

1000 PM CDT SUN JUN 20 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWESTERN IOWA

       SOUTHWESTERN MINNESOTA

       NORTHEASTERN NEBRASKA

       SOUTHEASTERN SOUTH DAKOTA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 1000 PM UNTIL

500 AM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTH

NORTHWEST OF CHAMBERLAIN SOUTH DAKOTA TO 15 MILES EAST NORTHEAST

OF SPENCER IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 359...WW 360...WW 361...



DISCUSSION...A CLUSTER OF SUPERCELLS IN CENTRAL SD ARE EXPECTED TO

BE MAINTAINED E/ESEWD OVERNIGHT AS LOW LEVEL JET INTENSIFIES AND

STORMS MOVE INTO AN ENVIRONMENT WITH MODERATE TO STRONG INSTABILITY.

ALSO...LOW LEVEL JET SHOULD HELP TO GENERATE OTHER ELEVATED

THUNDERSTORMS. LARGE HAIL WILL BE THE MAIN THREAT...THOUGH IF STRONG

OUTFLOWS CAN CONGEAL INTO A LINE SEGMENT...THE THREAT FOR WIND

DAMAGE WOULD BE ENHANCED.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 27030.





...IMY

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