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WWUS20 KWNS 102223

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URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 641

NWS Storm Prediction Center Norman OK

625 PM EDT Tue Sep 10 2019



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Central Lower Michigan

  Lake Huron



* Effective this Tuesday evening from 625 PM until 1100 PM EDT.



* Primary threats include...

  Isolated damaging wind gusts to 70 mph possible

  Isolated large hail events to 1 inch in diameter possible

  A tornado or two possible



SUMMARY...Scattered thunderstorms will likely persist through late

evening while spreading eastward across central Lower Michigan.  The

storm environment appears favorable for some supercell structures

capable of producing damaging gusts, marginally severe hail, and

perhaps a tornado or two.



The severe thunderstorm watch area is approximately along and 40

statute miles north and south of a line from 20 miles north of Grand

Rapids MI to 40 miles southeast of Bad Axe MI. For a complete

depiction of the watch see the associated watch outline update

(WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 640...



AVIATION...A few severe thunderstorms with hail surface and aloft to

1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few

cumulonimbi with maximum tops to 500. Mean storm motion vector

27035.



...Thompson

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