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185 

WWUS20 KWNS 122041

SEL8

SPC WW 122041

MTZ000-WYZ000-130400-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 318

NWS Storm Prediction Center Norman OK

245 PM MDT Mon Jun 12 2017



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  South Central Montana

  Northern Wyoming



* Effective this Monday afternoon and evening from 245 PM until

  1000 PM MDT.



* Primary threats include...

  Scattered large hail likely with 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...Scattered strong to severe thunderstorms are expected to

develop and spread across the watch area this afternoon and evening.

 Large hail and damaging winds will be possible in the strongest

cells, along with the potential of an isolated tornado.



The severe thunderstorm watch area is approximately along and 80

statute miles north and south of a line from 15 miles north

northwest of Livingston MT to 55 miles north northeast of Casper WY.

For a complete depiction of the watch see the associated watch

outline update (WOUS64 KWNS WOU8).



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 316...WW 317...



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 400. Mean storm motion vector

21035.



...Hart

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