Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
103 FXUS65 KBOI 011705 AFDBOI Area Forecast Discussion National Weather Service Boise ID 1005 AM MST Mon Dec 1 2025 .DISCUSSION...A weak cold front will move over the area late tonight into Tuesday morning. Increasing clouds expected later this afternoon, with snow showers over the mountains this evening. Sprinkles possible in the Snake Basin. As the cooler air aloft moves overhead on Tuesday, rain and snow showers develop during the afternoon with the daytime heating. Dry conditions return for Thursday and Friday. Current forecast reflects this, no updates. && .AVIATION...Generally VFR. Localized MVFR/IFR in fog/low stratus this morning near the Magic Valley, KBKE, and in mtn valleys. Conditions improving to VFR through the morning. MVFR/IFR conditions returning across the central ID mountains late this afternoon in low ceilngs and light snow showers. Isolated showers expanding across the area Tuesday morning. Snow levels: 2.5-3.5 kft MSL. Surface winds: Variable up to 12kt. Winds aloft at 10kft MSL: KBOI...VFR under increasing mid-high clouds. A 20% chance of rain/snow mix Tuesday morning. Surface winds: Light and variable. && .PREV DISCUSSION... SHORT TERM...Today through Wednesday night...Clear, cold wx in most of our CWA early this morning but satellite showed either fog or stratus across northern Gooding and Lincoln Counties. Webcams suggest stratus. Same in Baker County/OR. Cold, dry northerly flow aloft will maintain quiet wx today with light winds and slightly below normal temps. The upper air pattern has an upper ridge in the north Pacific along 130W and a short wave trough in the Gulf of Alaska. The trough is forecast to move north of the ridge and onto the BC coast today, then southward in BC tonight and into our area Tuesday, much like the weekend trough that brought light snow to our CWA. The new trough should also bring light snow. Latest MOS products indicate at most about a half-inch, but up to 3 inches may accumulate on northern peaks and in se Owyhee County along the NV border. Temperatures will also be similar to the previous event, so roads below 4500 feet should become only wet with little impact on travel. The trough and light snow should exit into NV Wednesday morning followed by clearing skies and breezy northwest winds. LONG TERM...Thursday through Monday...An upper level ridge off the coast will begin to weaken on Thursday. This will allow the jet stream to move south, ushering in wetter conditions as early as Thursday night and Friday and continuing into early next week. Strong westerly to northwesterly flow aloft is expected to develop across the Pacific Northwest, with Pacific moisture and embedded shortwave troughs resulting in periodic precipitation across our area. There is good ensemble agreement about the overall pattern. Without a strong northerly component to the flow, these systems should be fairly mild with mainly rain in the lower elevations and rain and snow in the mountains. The first impulse is expected to move through Friday into early Saturday. This will bring increasing precipitation chances on Friday, peaking Saturday morning at around 40-60% in the lower elevations and 60-90% in the mountains. Snow levels should rise with the warm front associated with this system to around 5500-7000 feet by Friday night, then trend lower as cooler air aloft arrives. Snow levels Saturday night through Monday are forecast to average 3500-5000 feet, with fluctuations higher and lower as additional impulses pass through the area. Individual system timing and strength are uncertain, but this pattern will continue a 10-30% chance of precipitation in the lower elevations and 30-60% in the mountains. Moderate to heavy snow totals will be possible through early next week on higher peaks. Temperatures are expected to average 5-10 degrees above normal through the period, and the active pattern will result in breezy conditions. && .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 DISCUSSION...KA AVIATION.....NF SHORT TERM...LC LONG TERM....ST