

000 

WWUS20 KWNS 291901

SEL2

SPC WW 291901

MIZ000-LHZ000-300100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 662

NWS STORM PREDICTION CENTER NORMAN OK

300 PM EDT WED AUG 29 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN LOWER MICHIGAN

       LAKE HURON



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 300 PM UNTIL

900 PM 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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHEAST OF

BAD AXE MICHIGAN TO 25 MILES SOUTH OF JACKSON MICHIGAN.  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.



DISCUSSION...ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP

AND MOVE EWD ACROSS WW THROUGH THE EARLY EVENING AHEAD OF SURFACE

COLD FRONT NOW MOVING SSEWD ACROSS NRN LOWER MI.  AIR MASS IS

MODERATELY UNSTABLE AHEAD OF THE FRONT...WITH 25-35 KT EFFECTIVE

SHEAR SUPPORTING ORGANIZED LINES AND POSSIBLY SUPERCELLS.  DAMAGING

WINDS AND LARGE HAIL ARE EXPECTED WITH THE MORE INTENSE CORES.



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 26025.





...EVANS

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