Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
688 FXUS65 KBOI 191028 AFDBOI Area Forecast Discussion National Weather Service Boise ID 328 AM MST Wed Nov 19 2025 .SHORT TERM...Today through Friday night...Light rain showers and stratus continue across much of the region this morning ahead of a weak upper level trough slowly moving east. Mainly low stratus is trapped in the lower valley this morning, stretching from Burns, Oregon through the Western Magic Valley. Light showers associated with the weak trough have helped dissipate the low stratus in Baker Valley and will likely help dissipate the stratus in the Lower Treasure Valley and the West Central Mountains later this morning. Fog is not expected to be a widespread issue this morning along the I 84 corridor, though light showers could bring some wet roads during the morning commute. Stratus is likely to remain across much of the Western Snake Plain into the afternoon before increased winds aloft associated with the next upper level system help erode the remaining clouds. The only area that may not see any improvement or brief improvement will be Burns, where stratus could remain in place through the late evening. This will primarily affect high temperatures today, as the delayed stratus dissipation could keep the valley a few degrees cooler than yesterday. The next system will bring scattered showers across much of the area starting late tonight as the upper level trough reaches the Pacific Northwest coast. This will continue through Thursday as a closed low forms to the west and moves south southeast into southern California/Arizona Thursday night. The best chance for precipitation will be Thursday morning with a 20 to 40 percent chance for light accumulations. Snow levels remain between 6000 to 7000 feet MSL. A weak ridge builds across the area following the low moving south for Friday, which could return the inversion for valley stratus and fog. Peak daytime valley temperatures are expected to remain in the lower 50s today through Friday, with nighttime temperatures dropping into the upper 30s. Again, low clouds, especially Thursday and Friday morning, could keep temperatures warmer overnight. .LONG TERM...Saturday through Wednesday...An upper-level ridge axis will be overhead to begin Saturday, with flow being weak aloft. This should persist our current pattern of valley fog/stratus overnight and early morning. Getting into Sunday, the closed low that traversed California will continue its trek east into the four corners region, with an upper-level shortwave trough moving across the U.S./Canada border. This provides a more zonal flow pattern into Monday. At some point in time after midday Monday, the shortwave upper-level trough traversing the U.S./Canada border will sag a cold front through the region. As is typical this far out, timing is quiet varied between long range models, but they do seem to agree between evening Monday and overnight into Tuesday. This will cause some PoPs in higher terrain and closer to normal temperatures. Upper- level ridging looks to build following into Wednesday. && .AVIATION...MVFR-LIFR in areas of fog/low stratus, especially in SE Oregon, west-central Idaho mountains, and the Snake River Plain. Light precip for E Oregon and W-central Idaho Wednesday morning. Some Flight Cat improvement expected by mid-day Wed, except for lingering low ceilings over SW Idaho mountains and E Oregon. Surface winds: variable less than 8kt. Winds aloft at 10kft MSL: S to SW 5- 15 kt. .KBOI...Predominantly MVFR from persistent low stratus in the upper Treasure Valley through late morning. A 20-30% chance of IFR/LIFR ceilings occurring until 18z. Impact on flight category not expected to be impacted by fog at this time. Small (10-15%) chance of light rain through morning. Surface winds: light and variable. && .AIR STAGNATION...Conditions remain borderline in regards to a prolonged stagnantion event. Mixing heights of 1800-2500 feet AGL and light winds are expected today through Friday. Expect fog and stratus today with a system on Thursday bringing light rain that could possibly breaking it up, especially in the Snake Plain which gets into easterly winds. The weekend will see a low-amplitude ridge which will keep dry and stable conditions in place along with low level moisture. && .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...JDS LONG TERM....CH AVIATION.....CH AIR STAGNATION...JDS