textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Continued very warm, dry days through Friday.

- Much cooler, with showers, Saturday through Tuesday.

- Significant rainfall possible in Idaho next week, but confidence remains low.

SHORT TERM /Through Friday Night/

Issued 208 PM MDT WED OCT 7 2026 An upper level ridge will continue warm, dry days through Friday. Highs temps will reach the 80s in the lower valleys, near daily record highs. Nights will continue cool with lows in the 40s to lower 50s in the valleys and 30s in the mountains. West winds will increase Friday afternoon, especially south of the Lower Snake Basin as a cold front approaches from the northwest. The front should pass through our CWA early Saturday morning, with the supporting upper low now forecast to pass through eastern OR Saturday night and Sunday on its way to the California coast Monday. This track is again a little west of the track forecast by yesterday's models. The westward adjustment means that coldest air will pass through Oregon, while Idaho remains under milder but also moister southerly flow aloft. Significant rainfall remains possible in Idaho Sunday through Tuesday, but it is still unclear where the western boundary of precipitation will finally set up. In any case, Idaho looks wetter than Oregon.

LONG TERM /Saturday through Wednesday/

Issued 208 PM MDT WED OCT 7 2026 Saturday max temperatures will trend ~20 degrees cooler than Friday's max temps in the wake of a strong cold front. Precipitation will spread into the area Saturday, with highest chances expected across the West-Central/Central Idaho and Boise Mountains. Snow levels will lower from northwest to southeast throughout the day, allowing for light snow accumulations in west-central Idaho above 7500 feet MSL by Saturday night. Cold air advection from the northwest will continue into Sunday, resulting in max temperatures lowering by an additional 5-10 degrees. High elevation light snow will continue over the West- Central/Central Idaho mountains through Sunday. Meanwhile, hurricane remnants originating from the eastern Pacific will carry a significant bout of moisture northeastward through the western U.S. The bulk of the precipitation is expected to reach the Northern Rockies by mid-Sunday and continue into Monday, with the western edge of the precipitation clipping southwest Idaho. While the exact path of moisture is still a bit uncertain, higher confidence for notable precipitation is currently anticipated for the SW Idaho Highlands, Magic Valley, Camas Prairie, and the Central Idaho Mountains, with lower chances farther west and north. Precipitation from this system will taper Monday night as both the parent trough and tropical moisture exit the area. Some guidance members are indicating a secondary, colder trough could usher into E Oregon and SW Idaho late Tuesday or Wednesday, while other members suggest a slight blocking pattern that would result in drier, warmer conditions.

AVIATION /00Z Thursday through Friday/

Issued 559 PM MDT WED OCT 7 2026 VFR and clear, except areas of smoke/haze reducing visibility near prescribed burns. Surface winds: variable less than 12 kt. Winds aloft at 10kft MSL: W-NW 5-15 kt.

KBOI...VFR and clear. Surface winds: variable around 4 kt, becoming SE tonight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Fire Weather Watch Friday afternoon for IDZ423-426. OR...None.