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WWUS20 KWNS 311754

SEL7

SPC WW 311754

MIZ000-WIZ000-LHZ000-LMZ000-LSZ000-010200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 407

NWS STORM PREDICTION CENTER NORMAN OK

155 PM EDT TUE MAY 31 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN LOWER AND MUCH OF UPPER MICHIGAN

       NORTHEAST WISCONSIN

       LAKE HURON

       LAKE MICHIGAN

       LAKE SUPERIOR



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

1000 PM EDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST

SOUTHWEST OF IRON MOUNTAIN MICHIGAN TO 40 MILES NORTHEAST OF

ALPENA MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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...SCATTERED THUNDERSTORMS ARE EXPECTED TO INTENSIFY

ACROSS THE WATCH AREA THIS AFTERNOON AS A STRONG UPPER TROUGH

APPROACHES FROM THE WEST.  MODERATE INSTABILITY AND FAVORABLE WINDS

ALOFT WILL PROMOTE ORGANIZED STORMS CAPABLE OF DAMAGING WINDS AND

LARGE HAIL.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 25040.





...HART

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