Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
522 FXUS65 KBOI 290947 AFDBOI Area Forecast Discussion National Weather Service Boise ID 247 AM MST Sat Nov 29 2025 .SHORT TERM...Today through Monday night...Friday`s cold front and afternoon wind dried out the air mass, and there is less fog in the valleys than the previous two nights. The air is also colder. Snow level will stay near valley floors when the next upper trough (currently in western BC) comes in tonight. The trough will spread a dusting to an inch of snow over all areas overnight, continuing Sunday morning south of the Snake River in ID, then ending early Sunday afternoon. For the lower southern valleys this will be the first snowfall of the season. Snow may briefly cover main roads around sunrise Sunday. Roads should become wet by mid-morning, with any remaining snow melting by midday as temps rise through the 30s. Skies will clear Sunday night. Lingering moisture from the melted snow will develop patchy fog in the valleys Sunday night and Monday morning. Higher valleys and basins will keep their new snow cover and may become very cold Monday morning as heat radiates off the snow out into space. After skies clear Monday morning, Monday should be mostly sunny but begin to cloud up from the north later on as the next upper trough approaches from the north. A 30 to 60 percent chance of light snow will spread south into our CWA late Monday night with best chance in the west central Idaho mountains. .LONG TERM...Tuesday through Saturday...An upper level trough will move across our area from northwest to southeast on Tuesday. Moisture will be limited with this system, resulting in light precipitation amounts. Precipitation chances are 30-50% in the valleys and 50-80% in the mountains. Snow levels will be around 2500-3500 feet, resulting in snow in the mountains and a rain/snow mix in the valleys. With snow levels near valley floors, there is around a 20% chance of accumulating snow in the Treasure and Magic valleys. Snow amounts of a couple inches will be possible in the mountains. This system will also bring breezy winds and slightly below normal temperatures. After the trough exits the area on Wednesday, the large-scale pattern will remain amplified through Friday with a ridge in the eastern Pacific and trough in the central U.S. As a result, cool and mostly dry northwesterly flow will keep temperatures near to slightly below normal with a 20-40% chance of snow in the mountains. On Saturday, the ridge is favored to weaken, allowing potential for Pacific moisture to return to the area. However, how much/when the ridge weakens and how much moisture remains uncertain. The net result is a 20-60% chance of rain/snow and an uptick in temperatures, with snow levels around 4000-6000 feet. && .AVIATION...Areas of LIFR/IFR stratus/fog this morning, though less coverage than Friday. Most likely in the Magic Valley and sheltered valleys of SE Oregon. Mainly VFR today as fog dissipates by late morning, with high clouds overhead. Snow will develop N to S mainly after 06Z/Sun with MVFR to LIFR conditions and mountain obscuration. Snow levels on valley floors with light accumulations. Surface winds: E-SE 5-15 kt. Winds aloft at 10kft MSL: NW 5-15 kt, becoming W-SW 10-25 kt after 18Z/Sat. KBOI...Low stratus/fog along the foothills this morning. Less than 30% chance of LIFR conditions directly impacting the terminal. Any potential for fog will end by 15-16Z. Surface winds light and variable early this morning, becoming SE 8-15 kt by mid morning. A 50% chance of snow developing at the terminal 08-13Z/Sun with MVFR/IFR conditions in snow. Less than a half inch of snow accumulation expected. Sunday Outlook...Snow showers decreasing N to S in the morning, with remaining accumulation limited to near the Nevada border. Snow levels on valley floors. MVFR to LIFR in snow and mountain obscuration in the morning, with mainly VFR conditions by the afternoon as snow ends and low clouds decrease. Surface winds: NW 5-15 kt with afternoon gusts 15-25 kt. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...LC LONG TERM....ST AVIATION.....ST