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209 

WWUS20 KWNS 311906

SEL9

SPC WW 311906

IDZ000-NVZ000-WYZ000-010200-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 139

NWS Storm Prediction Center Norman OK

110 PM MDT Thu May 31 2018



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Southern and Eastern Idaho

  Northeast Nevada

  Northwest Wyoming



* Effective this Thursday afternoon and evening from 110 PM until

  800 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



SUMMARY...In advance of an upper trough, ample heating in

conjunction with steep lapse rates and strengthening winds aloft

will support severe storms including the possibility of some

supercells. Large hail and damaging winds will be possible through

the afternoon.



The severe thunderstorm watch area is approximately along and 85

statute miles east and west of a line from 60 miles south southeast

of Owyhee NV to 20 miles east northeast of West Yellowstone MT. For

a complete depiction of the watch see the associated watch outline

update (WOUS64 KWNS WOU9).



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 136...WW 137...WW 138...



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

24030.



...Guyer

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