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WWUS20 KWNS 091938

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URGENT - IMMEDIATE BROADCAST REQUESTED

Tornado Watch Number 417

NWS Storm Prediction Center Norman OK

240 PM CDT Mon Aug 9 2021



The NWS Storm Prediction Center has issued a



* Tornado Watch for portions of

  Northern Illinois

  Extreme northwestern Indiana

  Lake Michigan



* Effective this Monday afternoon and evening from 240 PM until

  1000 PM CDT.



* Primary threats include...

  A couple tornadoes possible

  Scattered damaging wind gusts to 70 mph possible

  Isolated large hail events to 1.5 inches in diameter possible



SUMMARY...Severe storms are expected to develop in clusters or short

bands across northern Illinois this afternoon, and storms will

spread east-southeastward through late evening.  The storm

environment favors a mix of clusters and embedded supercells capable

of producing a couple of tornadoes, damaging winds of 60 to 70 mph,

and isolated large hail of 1 to 1.5 inch diameter.



The tornado watch area is approximately along and 45 statute miles

north and south of a line from 30 miles southwest of Rockford IL to

85 miles east of Marseilles IL. For a complete depiction of the

watch see the associated watch outline update (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



REMEMBER...A Tornado Watch means conditions are favorable for

tornadoes and 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.



&&



AVIATION...Tornadoes and 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 550. Mean

storm motion vector 30025.



...Thompson

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