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SEL1 URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 641 NWS Storm Prediction Center Norman OK 240 PM MDT Tue Aug 20 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southwest and Central Montana * Effective this Tuesday afternoon and evening from 240 PM until 1000 PM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms will develop over the mountains of southwest Montana this afternoon and spread quickly eastward across the watch area through the evening. Damaging wind gusts are the main threat with the strongest storms. The severe thunderstorm watch area is approximately along and 85 statute miles north and south of a line from 20 miles north of Dillon MT to 125 miles east northeast of Lewistown MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). 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 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25030. ...Hart