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000 

WWUS20 KWNS 260036

SEL8

SPC WW 260036

MIZ000-LMZ000-260500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 238

NWS STORM PREDICTION CENTER NORMAN OK

835 PM EDT FRI APR 25 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST LOWER MICHIGAN

       LAKE MICHIGAN



EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 835 PM

UNTIL 100 AM EDT.



HAIL TO 1.5 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 40

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES WEST

NORTHWEST OF PELLSTON MICHIGAN TO 25 MILES SOUTHWEST OF ROBEN

HOOD MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 231...WW 232...WW

233...WW 234...WW 235...WW 237...



DISCUSSION...CONVECTION WILL CROSS LAKE MI AND OVERSPREAD NW LOWER

MI THE NEXT FEW HOURS IN ADVANCE OF A MID LEVEL TROUGH AND SURFACE

COLD FRONT MOVING EWD OVER WI.  RELATIVELY STEEP MID LEVEL LAPSE

RATES AND EFFECTIVE BULK SHEAR IN EXCESS OF 40 KT WILL SUPPORT A

THREAT FOR ORGANIZED STORMS CAPABLE OF PRODUCING LARGE HAIL AND

DAMAGING GUSTS.



AVIATION...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 24035.





...THOMPSON

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