


Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
947 FXUS65 KBOI 180903 AFDBOI Area Forecast Discussion National Weather Service Boise ID 303 AM MDT Sat Oct 18 2025 .SHORT TERM...Today through Monday night...Weak ridging today ahead of the next system for Sunday will bring warm and dry conditions. As we enter inversion season, mountains will tap into warming aloft as high temperatures rise 2 to 5 degrees over yesterday`s, while sheltered mountain valleys and lower elevations will see high temperatures remain unchanged or even a couple of degrees cooler than today. The next system approaches the Pacific Northwest coast today and will push eastward with a cold frontal passage on Sunday. The frontal passage across the area is expected between 7 AM MDT and 3 PM MDT Sunday, with no significant change seen in the guidance. The greatest confidence for precipitation remains across the mountains of east central Oregon and west central Idaho. Confidence is lower across central Malheur, Harney counties, and the lower Snake Plain, due to a large variance in high res guidance which has been reflected in the forecast with a low chance (15 to 20 percent) for showers developing along the front in these areas. Areas along the Nevada border look to remain dry through the weekend. Snow levels will drop behind the front on Sunday, allowing for minor accumulations (less than 2 inches) above 6500 to 7000 feet. Southerly winds will pick up ahead of the front on Sunday, mostly across higher terrain where gusts of 20 to 30 mph are expected. The frontal passage Sunday afternoon brings a wind shift to the west northwest and increases the gust potential to 25 to 40 mph across the entire area. Showers will continue across the west central mountains of Idaho into Monday under cool and breezy northwesterly flow. This will keep temperatures about 5 to 7 degrees below normal. .LONG TERM...Tuesday through Saturday...A ridge of high pressure will build over the Intermountain West Tuesday through Friday morning, bringing slightly above normal temperatures and dry conditions to the region. Temperatures will be in the upper 60s to low 70s on Thursday and Friday in valley locations with light winds across the area. A significant change looks to move in late Friday, with a trough over the Gulf of Alaska deepening bringing an atmospheric river into the Pacific Northwest. This will bring breezy winds and widespread precipitation into the region late Friday into Saturday. Southwest flow ahead of the main cold frontal passage on Saturday will keep snow levels elevated around 7000-8000 feet. This will drop and lead to a higher potential for heavy mountain snow accumulations by late Saturday. Model agreement remains high in the passage of this system, but there remains discontinuity in precipitation totals and timing with ensemble and deterministic solutions. && .AVIATION...VFR. Low confidence in scattered stratus deck near KBOI- KONO and near KBKE. Areas of LLWS over the Magic Valley early this morning. Surface winds: W-NW 5-15 kt with occasional gusts to 25 kt, dropping to SW-W 5-10 kt by Sat/10Z then becoming E-SE 5-15 kt after Sun/00Z. Winds aloft at 10kft MSL: W-NW 20-40 kt. KBOI...VFR with a few low stratus clouds this morning. Surface winds: variable becoming NW-W 8-12 kt becoming SE 5-8 kt after Sat/22Z. Sunday Outlook...Increasing clouds with scattered showers north of a KBNO-KMUO line after Sun/12Z. Snow levels during precip drop from 9000 ft MSL to 5500 ft MSL by Sun evening. Surface winds: SW-SE 10- 20 kt with gusts up to 40 kt. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Frost Advisory until 9 AM MDT this morning IDZ012-014-016. OR...Frost Advisory until 9 AM MDT /8 AM PDT/ this morning ORZ064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...JDS LONG TERM....SA AVIATION.....SA