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WWUS20 KWNS 031837

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 231

NWS STORM PREDICTION CENTER NORMAN OK

235 PM EDT THU MAY 3 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN LOWER MICHIGAN

       LAKE MICHIGAN



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 235 PM UNTIL

900 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 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTH

NORTHWEST OF BENTON HARBOR MICHIGAN TO 25 MILES EAST SOUTHEAST OF

BAD AXE MICHIGAN.  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 229...WW 230...



DISCUSSION...EXPECT TSTMS TO INCREASE ALONG WARM FRONT AND WITHIN

WARM SECTOR ESTABLISHED ACROSS SRN LOWER MI. TEMPS IN THE 80S AND

DEWPOINTS IN THE 60S WERE CONTRIBUTING TO MLCAPE VALUES AROUND 2000

J/KG. SHEAR AND FORCING NEAR/ALONG AND NORTH OF THE FRONT SHOULD BE

SUFFICIENT TO SUSTAIN INCREASINGLY PERSISTENT UPDRAFTS ALONG WITH

SOME POTENTIAL FOR SUPERCELL STRUCTURE AND LARGE HAIL. WITH

TIME...SHEAR AND DEEP-LAYER FLOW MAY ALSO STRENGTHEN ACROSS THE WARM

SECTOR WITH THE CHANCE FOR STORMS IN THE FORM OF LINE SEGMENTS

POSSIBLY  INCREASING AND POSING A DAMAGING WIND THREAT.



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 26025.





...CARBIN

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