Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
594 FXUS65 KMSO 161833 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1233 PM MDT Thu May 16 2024 .DISCUSSION...A trough of low pressure is seen in GOES Water Vapor imagery this afternoon across British Columbia. As the trough continues to approach and replace the existing ridge of high pressure, the gradient will increase, giving us higher confidence for west-southwest winds of 20-40 mph range, with locally higher gusts in northwest Montana mountain areas through this evening. The aforementioned trough and associated surface cold front will move across the region tonight into Friday. Additional wind advisories have been issued for the Missoula/Bitterroot valley, Lemhi County, ID, and Butte/Blackfoot region, where frequent gusts of 40 mph or greater are expected by Friday afternoon. As the atmosphere destabilizes following the trough passage, convective showers, including isolated thunderstorms will develop, increasing the risk of isolated wind gusts in excess of 50 mph. NBM 24-hr max wind gusts probabilities for 50 mph or greater highlight the I-90 corridor north of Butte to Garrison Junction and the mountain areas across west-central MT as the primary areas of concern, with probabilities in the 50-80% range. Saturday will provide a brief break in between weather systems, before the next Pacific system drops down from the northwest on Sunday. Ensemble guidance suggests additional Pacific systems will move across the region early next week. Stay tuned for further details in the coming days! /Lukinbeal && .AVIATION...Southwest-west wind gusts of 20-30kts will continue through 17/0200-0400Z across the Northern Rockies as the pressure gradient tightens with an approaching trough of low pressure moving into British Columbia. A pacific cold frontal passage is expected tonight into Friday morning, with a line of showers and lower ceilings (around 5000 ft AGL) overnight into Friday morning. Westerly winds will once again ramp up by late Friday morning following the frontal passage, with gusts of 25-40kts. /Lukinbeal && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Wind Advisory from noon to 8 PM MDT Friday for Butte/Blackfoot Region...Missoula/Bitterroot Valleys. Wind Advisory until 8 PM MDT this evening for Flathead/Mission Valleys. Wind Advisory until 8 PM MDT this evening for Butte/Blackfoot Region...Missoula/Bitterroot Valleys. ID...Wind Advisory from noon to 8 PM MDT Friday for Eastern Lemhi County...Western Lemhi County. && $$