

138 

WWUS20 KWNS 021610

SEL3

SPC WW 021610

MIZ000-LHZ000-LMZ000-022100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 823

NWS STORM PREDICTION CENTER NORMAN OK

1210 PM EDT FRI SEP 2 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN LOWER MICHIGAN

       LAKE HURON

       LAKE MICHIGAN



EFFECTIVE THIS FRIDAY AFTERNOON FROM 1210 PM UNTIL 500 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST

NORTHWEST OF MANISTEE MICHIGAN TO 5 MILES NORTH OF OSCODA

MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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...LEADING EDGE OF A COLD POOL ASSOCIATED WITH A DECAYING

ERN WI MCS HAS GENERATED NEW MULTICELL STORMS OVER NRN LK MI LATE

THIS MORNING.  GRB VWP EXHIBITS RATHER STRONG WLY FLOW FROM 3-5KM

/AOB 50 KTS/ ALONG SRN FRINGE OF AN MCV OVER NERN WI. THIS FLOW WILL

EVOLVE ENE ACROSS NRN LWR MI THIS AFTN. STORMS NOW FORMING ALONG THE

LK MI SHORELINE WILL LIKELY BRIEFLY ORGANIZE INTO BOWS GIVING LOCAL

CORRIDORS OF SVR/DMGG WIND GUSTS AMIDST 1500 J/KG OF MLCAPE/STEEP

LAPSE RATES.



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 450. MEAN STORM

MOTION VECTOR 24045.





...RACY

