

220 

WWUS20 KWNS 042042

SEL2

SPC WW 042042

MIZ000-LEZ000-LHZ000-050200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 462

NWS STORM PREDICTION CENTER NORMAN OK

445 PM EDT WED JUL 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHEAST LOWER MICHIGAN

       LAKE ERIE

       LAKE HURON



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 445 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 NORTH AND SOUTH OF A LINE FROM 45 MILES NORTHWEST

OF LANSING MICHIGAN TO 20 MILES EAST SOUTHEAST OF MOUNT CLEMENS

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...CONTINUE...WW 460...WW 461...



DISCUSSION...STORMS ARE BEGINNING TO DEVELOP ALONG A CONFLUENCE BAND

ACROSS CENTRAL/SE LOWER MI...WHERE A HOT/DEEPLY MIXED AIR MASS

IMPINGES ON THE BOUNDARY.  ADDITIONALLY...A SUBTLE MIDLEVEL SPEED

MAX IS MOVING SEWD OVER NRN LOWER MI.  GIVEN THE STRONG INSTABILITY

AND MODEST NWLY MIDLEVEL FLOW ENVIRONMENT...THERE WILL BE THE

POTENTIAL FOR ORGANIZED STORM CLUSTERS WITH THE POTENTIAL TO PRODUCE

LARGE HAIL AND DAMAGING WINDS THROUGH LATE EVENING.



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 550. MEAN STORM

MOTION VECTOR 31030.





...THOMPSON

