Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
792 FXUS65 KBOI 292142 AFDBOI Area Forecast Discussion National Weather Service Boise ID 242 PM MST Sat Nov 29 2025 .SHORT TERM...Tonight through Monday night...High clouds continue to stream in from the northwest today as the next system moves into the area late this evening. Cool dry air continues to trickle down the Snake Plain today. East- southeast winds 10-20 mph this afternoon in the Snake Plain. Snow showers increase late this evening in eastern OR and overnight into Sunday morning in southwest ID as a weak system moves across the area. Cool dry air in the Snake Basin from east to southeast flow will limit snow amounts to under an inch due to sublimination in the low levels, while the higher terrain will generally see 1-2 inches of new snow. Snow showers taper off by Sunday afternoon with lingering low clouds and fog. Breezy northwest winds follow the system during the afternoon with clearing. Patchy fog possible on Monday morning. High clouds expected Monday afternoon with light winds. Next system arrives late Monday with showers developing in eastern OR late in the evening. .LONG TERM...Tuesday through Saturday...Come Tuesday, an upper level trough will dig down across our area from British Columbia. A consequence of this system digging down from mainland British Columbia is that moisture will be limited, with it removed from any Pacific moisture. None the less, this system will support precipitation chances of 30-50% in valleys, and 50-90% across higher terrain. With snow levels near valley floors Tuesday morning, Mountains could see 1-2 inches of additional snowfall with valley locations seeing a wintery mix. Ensembles have been pretty consistent the past few runs of putting down a measurable snowfall in the Treasure and western Magic Valleys on Tuesday. However limited accumulation is expected, and any snow that does accumulate will melt off pretty quickly with daytime highs climbing to the low 40s. Breezy conditions will also accompany this system Tuesday afternoon. As this system exits, an amplified pattern will remain with a high amplitude ridge off the west coast and troughing over the central/eastern CONUS, leaving our area under dry north/northwest flow. This flow will keep temperatures right around normal for this time of year in lower elevations, although upper-level subsidence will keep mountain temps leaning above normal. Uncertainty remains on when the ridge will begin to breakdown and when we can tap into some moisture, but it`s looking like sometime late this coming week is favored. The Euro and GFS ensembles have an uptick in moisture, ensemble mean values around the 90-95th percentile, but timing varies with the GFS bringing it in Friday and the Euro lagging it towards Saturday. This is resulting in increasing precipitation chances through Friday and into Saturday. Precipitations Friday afternoon are 20-50% generally confined north of the Snake Plain, expanding and increasing to 10-20% in and south of the Snake Plain with a 30-70% chance north (highest in the west Central Mountains). Temperatures Friday/Saturday will begin to lean above normal in lower elevations (staying above normal in higher elevations as well), with snow levels rising to 5-6kft MSL. && .AVIATION...VFR with increasing high clouds. Snow showers developing from N to S after Sun/06Z resulting in MVFR/LIFR conditions and mountain obscuration with low visibility and ceilings. Snow exiting our area by around Sun/18z. Snow Levels on Valley floors. Surface winds: E-SE 5-15 kt with gusts of 20-25 kt this afternoon in the Snake Plain. Winds aloft at 10kft MSL: Variable 5-20 kt, becoming W- NW 20-30 kt S and W of the Snake Plain, variable 5-20 kt north of the Snake Plain. KBOI...VFR Saturday. Snow showers developing Sunday morning, with a 50% chance of snow at terminal between Sun/8-13z. Uncertainty owed to dry surface air that will act to sublimate the snow before it makes it to the surface, accumulations under half an inch expected. MVFR/IFR conditions in snow. Surface winds: SE 10-15 kt with gusts up to 22 kt this afternoon, becoming W-NW 8-12 kt after Sun/08z. && .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...KA LONG TERM....NF AVIATION.....NF