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WWUS20 KWNS 080006

SEL9

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URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 339

NWS Storm Prediction Center Norman OK

605 PM MDT Tue Jul 7 2020



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Western South Dakota



* Effective this Tuesday night from 605 PM until Midnight 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...An ongoing thunderstorm cluster in southwest South Dakota

will develop northeastward, while a separate cluster in southeast

Montana will move into northwest South Dakota.  Both of these storm

clusters will be capable of producing damaging winds and large hail.

 There is also some chance for embedded supercell structures capable

of producing an isolated tornado.



The severe thunderstorm watch area is approximately along and 60

statute miles east and west of a line from 40 miles northeast of

Buffalo SD to 35 miles west southwest of Philip SD. 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 inches. Extreme turbulence and surface wind gusts to 60 knots. A

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

26035.



...Thompson

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