

692 

WWUS20 KWNS 111832

SEL9

SPC WW 111832

MTZ000-120100-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 569

NWS Storm Prediction Center Norman OK

1235 PM MDT Sun Aug 11 2019



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Southwest to central Montana



* Effective this Sunday afternoon and evening from 1235 PM until

  700 PM MDT.



* Primary threats include...

  Scattered damaging winds and isolated significant gusts to 75

    mph possible

  Scattered large hail and isolated very large hail events to 2.5

    inches in diameter possible

  A tornado or two possible



SUMMARY...Multiple supercells are expected to develop from southwest

into central Montana. Large hail will be the primary initial hazard,

but potential for severe wind gusts will increase later this

afternoon as storms likely grow upscale into a cluster.



The severe thunderstorm watch area is approximately along and 70

statute miles either side of a line from 45 miles west southwest of

Dillon MT to 25 miles southeast of Lewistown 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 500. Mean storm motion vector

22035.



...Grams

