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WWUS20 KWNS 102012

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URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 269

NWS Storm Prediction Center Norman OK

215 PM MDT Tue Jul 10 2018



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Central into northeastern Montana



* Effective this Tuesday afternoon and evening from 215 PM until

  900 PM MDT.



* Primary threats include...

  Scattered damaging winds and isolated significant gusts to 75

    mph likely

  Scattered large hail and isolated very large hail events to 2.5

    inches in diameter likely

  A tornado or two possible



SUMMARY...Thunderstorms are developing near and just northeast of

the higher terrain in south central Montana, and other storm

development is expected the next couple of hours into north central

Montana.  The storm environment will favor supercells initially with

the potential to produce isolated very large hail and damaging

winds.  Some clustering of convection is probable by this evening,

with an increasing threat for damaging winds.  An isolated tornado

cannot be ruled out due to storm interactions with a lingering

boundary across northeastern Montana this evening.



The severe thunderstorm watch area is approximately along and 95

statute miles north and south of a line from 65 miles west northwest

of Lewistown MT to 10 miles east southeast of Sidney 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.



&&



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

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

few cumulonimbi with maximum tops to 550. Mean storm motion vector

26030.



...Thompson

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