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461 

WWUS20 KWNS 082152

SEL1

SPC WW 082152

IAZ000-ILZ000-WIZ000-LMZ000-090400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 441

NWS STORM PREDICTION CENTER NORMAN OK

450 PM CDT WED JUN 8 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IOWA

       NORTHERN ILLINOIS

       SOUTHERN AND EASTERN WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 450 PM UNTIL

1100 PM 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 70

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES NORTH

NORTHWEST OF CEDAR RAPIDS IOWA TO 35 MILES EAST OF OSHKOSH

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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 440...



DISCUSSION...THUNDERSTORMS WILL INITIATE AND INCREASE IN COVERAGE

ALONG AND AHEAD OF A SEWD MOVING COLD FRONT. THE AIRMASS AHEAD OF

THE FRONT IS STRONGLY UNSTABLE WITH 40 TO 50 KT OF DEEP LAYER SHEAR

WHICH WILL RESULT IN A SEVERE THREAT DEVELOPING ACROSS THE WATCH

AREA FROM LATE THIS AFTERNOON INTO THE MID-EVENING. ALTHOUGH A

TORNADO OR TWO WILL BE POSSIBLE AS LOW-LEVEL FLOW INCREASES THIS

EVENING...THE MAIN THREATS ARE EXPECTED TO BE LARGE HAIL AND WIND

DAMAGE AS STORMS CONGEAL AND DEVELOP INTO A LINE-SEGMENT.



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.





...BROYLES/HART

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