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WWUS20 KWNS 171920

SEL0

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MTZ000-SDZ000-WYZ000-180300-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 100

NWS Storm Prediction Center Norman OK

120 PM MDT Thu May 17 2018



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Extreme Southeast Montana

  Western South Dakota

  Northeast Wyoming



* Effective this Thursday afternoon and evening from 120 PM until

  900 PM MDT.



* Primary threats include...

  Scattered large hail and isolated very large hail events to 2

    inches in diameter possible

  Scattered damaging wind gusts to 70 mph possible

  A tornado or two possible



SUMMARY...Storms developing over northeast Wyoming and western South

Dakota are expected to increase in intensity this afternoon and

spread northeast through the evening posing a threat for large hail

and damaging wind gusts.



The severe thunderstorm watch area is approximately along and 80

statute miles east and west of a line from 50 miles east northeast

of Buffalo SD to 70 miles south of Rapid City SD. 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.



&&



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

2 inches. Extreme turbulence and surface wind gusts to 60 knots. A

few cumulonimbi with maximum tops to 500. Mean storm motion vector

24025.



...Weiss

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