FXUS65 KMSO 240702 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 102 AM MDT Tue Mar 24 2026 .DISCUSSION... KEY MESSAGES: - Atmospheric River: Widespread precipitation, high elevation snow, and gusty winds through Wednesday. - Mountain Snow: Snow accumulations will primarily impact high elevations above 6,000 feet, with minor travel impacts on mountain passes. - Wind and Fire Risk: Strong winds arrive Wednesday. Combined with low humidity, confidence is growing for critical fire weather conditions east of the divide in Southwest Montana. - Mild Weekend: A warming trend begins Friday, bringing above- normal temperatures by Saturday. A quick shot of subtropical moisture-a short-lived Atmospheric River (AR) will arrive across north-central Idaho and northwest Montana by midafternoon today. This system is expected to deliver 0.5 to 1.5 inches of liquid precipitation across the higher terrain and along the Montana/Idaho border, with the heaviest totals in northwest Montana. Snow levels will rise sharply this afternoon, with rain falling above 7,000 feet through tonight. A potent cold front remains on track to arrive Wednesday morning, with snow levels falling quickly across northwest Montana, falling near 3,500 by Wednesday afternoon. Conversely, ahead of the front in southwest Montana and Lemhi County, snow levels will steadily rise to near 7,000 feet through Wednesday afternoon. By Wednesday night and into Thursday morning, snow levels will fall region-wide, transitioning any lingering showers to snow. While Lookout and Marias Passes could see a few inches of new accumulation, travel impacts are expected to remain minimal. The primary concern with this mid-week system remains the wind on Wednesday. A 40 to 60 knot low-level jet will set up over the Northern Rockies, creating widespread breezy to windy conditions. The strongest winds are anticipated across Lemhi County and into southwest Montana Wednesday afternoon, where there is a 50% to 70% chance of gusts exceeding 40 mph. While the higher terrain along the Continental Divide could see gusts up to 60 mph, western Montana valleys carry a 25% to 50% chance for gusts in the 30 to 40 mph range. Critical fire weather conditions are a major concern for Southwest Montana, east of the Divide within the East Beaverhead on Wednesday afternoon. As the winds peak, relative humidity values are forecast to drop into the teens. This combination of high wind and low humidity has prompted the issuance of a Fire Weather Watch. Following the frontal passage, temperatures will dip below seasonal normals on Thursday before a ridge of high pressure rebounds late in the week. This will initiate a notable warming and drying trend, with temperatures returning to above normal by Saturday. && .AVIATION... A fast-moving Atmospheric River (AR) arrives this afternoon, bringing widespread rain and terrain-obscuring clouds to north- central Idaho and northwest Montana. Ceilings and visibility reductions will become more common after 23/2100Z. Ceilings/Visibility: VFR conditions will deteriorate to areas of MVFR by mid-afternoon (approx. 21Z-00Z) across north-central Idaho and northwest Montana as widespread precipitation begins. Expect persistent mountain obscuration along the Montana/Idaho border and the Continental Divide through the period. Wind/Turbulence: Low-level wind shear (LLWS) and mechanical turbulence will become the primary hazards toward the end of the 24-hour period (approx 21-06z). Surface gusts of 25-40 kt are expected in western Montana valleys by late Wednesday morning as a cold front passes, with gusts exceeding 40 kt over ridges and through wind-prone canyons in southwest Montana and Lemhi County (near KTBM and KSMN) by Wednesday afternoon. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Fire Weather Watch from Wednesday afternoon through Wednesday evening for East Beaverhead. ID...None. && $$