SPC
SPC Severe Thunderstorm Watch 642
WW 642 SEVERE TSTM MT SD 212100Z – 220400Z 
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 642 NWS Storm Prediction Center Norman OK 400 PM CDT Wed Aug 21 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southeast Montana Western South Dakota * Effective this Wednesday afternoon and evening from 400 PM until 1100 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...Thunderstorms will develop across southeast Montana and western South Dakota through the afternoon and evening. The strongest cells may produce damaging winds and large hail. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 145 miles west northwest of Broadus MT to 25 miles north northeast of Philip SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). 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 500. Mean storm motion vector 25030. ...Hart
SPC – No watches are valid as of Wed Aug 21 04:02:02 UTC 2024
No watches are valid as of Wed Aug 21 04:02:02 UTC 2024.
SPC Severe Thunderstorm Watch 641
WW 641 SEVERE TSTM MT 202040Z – 210400Z 
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
SPC – No watches are valid as of Tue Aug 20 04:02:02 UTC 2024
No watches are valid as of Tue Aug 20 04:02:02 UTC 2024.
SPC Severe Thunderstorm Watch 640
WW 640 SEVERE TSTM ID MT 192050Z – 200400Z 
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 640 NWS Storm Prediction Center Norman OK 250 PM MDT Mon Aug 19 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Idaho Western and Central Montana * Effective this Monday afternoon and evening from 250 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 are forming over the mountains of northern Idaho and western Montana. These storms will intensify and organize through the afternoon and spread northeastward across the watch area. Damaging wind gusts will be possible in the strongest storms. The severe thunderstorm watch area is approximately along and 70 statute miles east and west of a line from 35 miles east southeast of Salmon ID to 35 miles northeast of Cut Bank MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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 639... 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 23025. ...Hart
SPC Severe Thunderstorm Watch 639
WW 639 SEVERE TSTM CO NE WY 191945Z – 200300Z 
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 639 NWS Storm Prediction Center Norman OK 145 PM MDT Mon Aug 19 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Colorado Nebraska Panhandle Southeast Wyoming * Effective this Monday afternoon and evening from 145 PM until 900 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...Thunderstorms are expected to build eastward off the foothills of this afternoon, spreading across the watch area. The strongest storms will pose a risk of large hail and locally damaging wind gusts. The severe thunderstorm watch area is approximately along and 35 statute miles east and west of a line from 25 miles southeast of Pueblo CO to 20 miles northwest of Chadron NE. 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 500. Mean storm motion vector 24025. ...Hart