Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
331 FXUS65 KBOI 111616 AFDBOI Area Forecast Discussion National Weather Service Boise ID 916 AM MST Tue Nov 11 2025 .DISCUSSION...Continued dry and mild through Thursday morning under high pressure aloft. A weak surface-based inversion will continue with afternoon temps in the lower valleys slightly cooler than at higher elevations. On Thursday the high pressure aloft will shift east, and moist, southwesterly flow will come into eastern OR ahead of an approaching Pacific cold front and upper trough. Showers will begin in eastern OR Thursday afternoon, then CWA-wide Thursday night as the cold front moves through. The frontal passage, and cooling aloft later on, should mix-out the inversion. && .AVIATION...VFR under mid/high-level clouds. Surface Winds: Variable up to 10 kt. Winds aloft at 10kft MSL: W 10-25 kt. KBOI...VFR. SE up to 5 kt this morning, becoming light and variable this afternoon. && .AIR STAGNATION...Weak surface-based inversion and limited mixing will continue through early Thursday as high pressure aloft and subsidence keep mixing heights near or slightly below 2 kft AGL in valleys. Mixing should deepen later Thursday as a Pacific surface cold front and upper trough approach Thursday, removing the inversion Thursday night. && .PREV DISCUSSION... SHORT TERM...Today through Thursday night...Mild and dry conditions continue today and through much of the short term as a ridge persists. An inversion remains over many lower valleys, with mixing heights near to less than 2 kft AGL. Temps today through Thursday will be 10-15 degrees above normal, with the warmest day being Wednesday. As southwesterly flow increases ahead of the trough later in the week, winds increase Wednesday and Thursday. A 15 to 30 percent chance of showers is expected across southeast Oregon and the central Idaho mountains late Wednesday night as the trough moves inland. Snow levels will be 8000 to 9000 feet MSL as the precipitation begins. Clouds will increase Wednesday as a high-amplitude trough strengthens over the West Coast. Isolated showers will develop late Thursday, with higher confidence early Friday as the trough and cold front move through the region. LONG TERM...Friday through Tuesday...A strong trough axis moves overhead Friday, with a cold front bringing precipitation and colder temperatures. In lower elevations there will be a 40-60% chance of precipitation late Thursday through Friday morning. At higher elevations it will be 80-90%. Similarly, the forecast rainfall totals are up to 0.15 inch for lower elevations, and up to 0.50 inch for higher. Temps will cool to just a few degrees above normal for this time of year, and snow levels drop to 5-6 kft MSL by Friday afternoon. Snow on ridges and high elevation passes will be 1-3 inches. After Sunday deterministic models depict a trough deepening in the region, consistent with ensemble clusters. Most clusters show the trough deepening over the area Tuesday morning, but one cluster and the GFS deterministic show another closed low off the SoCal coast forming. All this to say: while generally unsettled and colder weather is in store Monday/Tuesday, significant uncertainty remains in the details as of the latest runs. && .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...LC AVIATION.....NF AIR STAGNATION...LC/JM SHORT TERM...JM LONG TERM....JM