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765 

WWUS20 KWNS 201842

SEL7

SPC WW 201842

WIZ000-LMZ000-210100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 627

NWS STORM PREDICTION CENTER NORMAN OK

145 PM CDT FRI AUG 20 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN AND CENTRAL WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 145 PM UNTIL 800

PM 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 APPROXIMATELY ALONG AND 105

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTH OF LA

CROSSE WISCONSIN TO 50 MILES NORTHEAST OF MANITOWOC WISCONSIN.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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.



DISCUSSION...THUNDERSTORMS NOW INCREASING ALONG THE MS RIVER OVER

SOUTHEAST MN/NORTHEAST IA ARE EXPECTED TO SPREAD ACROSS THE WATCH

AREA THROUGH THE AFTERNOON AND EARLY EVENING.  STRONG INSTABILITY

AND SUFFICIENT VERTICAL SHEAR WILL PROMOTE MULTICELL STORMS CAPABLE

OF DAMAGING WINDS AND HAIL.  ENHANCED LOW LEVEL SHEAR NEAR THE WARM

FRONT OVER NORTHERN CENTRAL WI MAY RESULT IN AN ISOLATED SUPERCELL

AS WELL.



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 26030.





...HART

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