

203 

WWUS20 KWNS 102045

SEL0

SPC WW 102045

ILZ000-WIZ000-LMZ000-110300-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 420

NWS Storm Prediction Center Norman OK

345 PM CDT Tue Aug 10 2021



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Northern Illinois

  Southeastern Wisconsin

  Lake Michigan



* Effective this Tuesday afternoon and evening from 345 PM until

  1000 PM CDT.



* Primary threats include...

  Scattered damaging winds and isolated significant gusts to 75

    mph likely

  Scattered large hail events to 1.5 inches in diameter possible



SUMMARY...Thunderstorms across eastern Iowa will continue to expand

while spreading eastward and northeastward into Wisconsin and

Illinois through late evening.  The storm environment favors storm

clusters capable of producing damaging winds (some significant up to

75 mph) and occasional large hail.



The severe thunderstorm watch area is approximately along and 70

statute miles east and west of a line from 35 miles north northwest

of Oshkosh WI to 25 miles west southwest of Marseilles IL. For a

complete depiction of the watch see the associated watch outline

update (WOUS64 KWNS WOU0).



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 419...



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

1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A

few cumulonimbi with maximum tops to 600. Mean storm motion vector

27025.



...Thompson

