

838 

WWUS20 KWNS 251939

SEL2

SPC WW 251939

INZ000-MIZ000-OHZ000-LEZ000-LHZ000-LMZ000-260200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 182

NWS STORM PREDICTION CENTER NORMAN OK

340 PM EDT SAT APR 25 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF NORTHERN INDIANA

       LARGE PART OF LOWER MICHIGAN

       SMALL PART OF NORTHWEST OHIO

       LAKE ERIE

       LAKE HURON

       LAKE MICHIGAN



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 340 PM UNTIL

1000 PM EDT.



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 55

STATUTE MILES EITHER SIDE OF A LINE FROM 40 MILES EAST NORTHEAST

OF MOUNT CLEMENS MICHIGAN TO 30 MILES SOUTHWEST OF BENTON HARBOR

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.



OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 181. WATCH NUMBER 181 WILL NOT

BE IN EFFECT AFTER 340 PM EDT.



DISCUSSION...THUNDERSTORMS CONTINUE TO REDEVELOP AND MOVE ACROSS SRN

LWR MI AHEAD OF COLD FRONT.  WITH STRONG DEEP LAYER SHEAR AND STEEP

LOW LEVEL LAPSE RATES ALONG WITH MLCAPES TO 1000 J/KG...CONDITIONS

WILL REMAIN FAVORABLE FOR LINE SEGMENTS/BOWS AND ACCOMPANYING WIND

DAMAGE THREAT INTO THE EVENING HOURS.



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 450. MEAN STORM

MOTION VECTOR 24040.





...HALES

