Cottonwood Butte Snow Report

712 FXUS65 KMSO 270758 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 158 AM MDT Thu Aug 27 2026 .DISCUSSION... KEY MESSAGES: - Scattered thunderstorms today, with lightning and gusty outflow winds being the main threats. - A cold front arrives Saturday, bringing cooling temperatures, gusty westerly winds, and precipitation, focused along and south of about I-90. Satellite imagery early this morning indicates a circulation of low pressure spinning off the coast of southern British Columbia. This feature, along with a ridge of high pressure with its axis just east of the Continental Divide, will keep the Northern Rockies under southwest flow aloft going into the weekend. Pacific moisture from the southwest will bring chances for showers and thunderstorms again today. Model soundings show enough instability for showers to start as early as this morning for Lemhi County and southwest Montana. Instability increases this afternoon, when thunderstorm activity will spread further north. High resolution models indicate chances for thunderstorms across north-central Idaho and northwest and west-central Montana. A dry lower atmosphere will keep rain amounts on the low side, so primary impacts will be gusty outflow winds (30-50 mph) and frequent lightning. Expect windy conditions this afternoon across much of the Northern Rockies as the Pacific low moves inland and an upper level jet streak becomes situated over central Idaho and western Montana. Southern Idaho County, as well as Lemhi County and southwest Montana will be the breeziest, as gusts from the southwest reach about 30 mph this afternoon. As the low traverses the Canadian border on Friday, it will push a cold front across the Northern Rockies. Daytime high temperatures will drop down to the upper 70s to low 80s for Montana valleys and low 90s for the lower valleys of western Idaho. Widespread precipitation arrives on Saturday as the low moves further inland. Expect more fall-like temperatures as the weekend progresses. As far as precipitation goes, chances for wetting rain (more than 0.10 in) by Sunday will be about 70-80% for west-central and southwest Montana, as well as Lemhi County. Chances will be slightly better going east, and worse further west and north, with little to no precipitation for far northwest Montana. Temperatures rebound early next week, while ensemble solutions are indicating more unsettled weather later in the week. && .AVIATION...Gusty winds and chances for thunderstorms will be the main impacts to aviation today. Southwest winds gusting to 20-30 knots will increase this afternoon at all airfields. Chances for thunderstorms will also increase by about 27/2000Z. Model soundings show enough instability for isolated showers to start as early as this morning for KSMN and KBTM. Thunderstorm coverage this afternoon will be primarily over KSMN and KBTM. While the lower atmosphere remains dry, the primary threats from todays storms will be gusty outflow winds of 30-40 knots and frequent lightning. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$