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WWUS20 KWNS 151729

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 480

NWS STORM PREDICTION CENTER NORMAN OK

130 PM EDT THU JUL 15 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       MUCH OF LOWER MICHIGAN

       LAKE ERIE

       LAKE HURON



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 130 PM UNTIL

1000 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 60

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

SOUTHWEST OF JACKSON MICHIGAN TO 35 MILES NORTH NORTHEAST OF

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

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 479...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY TODAY AHEAD OF SURFACE FRONT PROGRESSING EWD ACROSS THE

STATE.  BREAKS IN THE CLOUDS COUPLED WITH BOUNDARY LAYER DEWPOINTS

IN THE 70S ARE YIELDING A MODERATELY UNSTABLE AIR MASS WITH MLCAPE

OF 1000-2000 J/KG.  WHEN COMBINED WITH 30-35 KT OF DEEP WLY

SHEAR...ENVIRONMENT IS SUPPORTIVE OF ORGANIZED CONVECTIVE BANDS WITH

EMBEDDED MARGINAL SUPERCELL STRUCTURES.  THE PRIMARY HAZARD WITH

THESE STORMS WILL BE SOME HAIL AND DAMAGING WIND GUSTS.



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 500. MEAN STORM

MOTION VECTOR 27030.





...MEAD

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