textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warm and mostly dry today and tomorrow ahead of a strong cold front late tomorrow night with scattered showers, isolated thunderstorms, high elevation snow, and gusty westerly winds.

- Breezy and much cooler Sunday, with lingering showers in northeast OR and the central ID mountains.

- Unsettled cool conditions through next Wednesday, then a warming and drying trend likely for the end of the week.

SHORT TERM /Through Sunday Night/

Issued 305 AM MDT FRI SEP 11 2026 Breezy westerly winds will linger over higher terrain this morning as a weak cold front continues tracking east. A short lived ridge of high pressure will build in later today into early Saturday, bringing temperatures about 3-5 degrees above normal for the region. Then, a strong low pressure system will move into the Pacific Northwest late Saturday with a strong cold front moving into southeast OR overnight. This front will then track into southwest ID by early Sunday morning. Southwest winds with gusts up to 40 mph, scattered showers, isolated thunderstorms, and much cooler temperatures will accompany this front. Current model runs track the low pressure and the bulk of the moisture into northern Idaho, keeping the best chances of precipitation over northern zones near Baker County, OR and Valley County, ID. Liquid equivalent precipitation amounts by Sunday will range from 0.50-0.80 inches, with snow levels dipping down to 6,500-7,500 feet MSL by Sunday night. Snowfall accumulations will likely be around 1-2 inches over high terrain.

LONG TERM /Monday through Friday/

Issued 305 AM MDT FRI SEP 11 2026 Low pressure will gradually move east early next week, but continued troughing will linger over the region, keeping temperatures slightly below normal on Monday and Tuesday. Another weak low pressure system will move in by Wednesday, bringing a low chance of precipitation over high terrain and another brief cool down. Model disagreement then increases with the evolution of that low; however, the majority of solutions favor ridging returning by late week, with dry conditions and temperatures 5-10 degrees above normal expected.

AVIATION /12Z Friday through Saturday/

Issued 600 AM MDT FRI SEP 11 2026

VFR. Scattered high clouds throughout the day. Surface winds: SW-NW 5-15 kt. Winds aloft at 10kft MSL: SW-W 25-35 kt.

KBOI...VFR with scattered high clouds. Surface winds: NW-N 4-8 kt, then E-SE 5-10 kt after 12/02Z.

Weekend Outlook...VFR with increasing SW surface winds in OR Saturday afternoon. Cold front with gusty southwest winds, widespread showers, and scattered thunderstorms late Saturday, mainly in Baker County, OR and north of the Snake Basin in ID. MVFR conditions and mountain obscuration in precip. Showers, mountain valley fog, and MVFR conditions continuing Sunday morning in west-central ID before improving in the afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Fire Weather Watch from Saturday afternoon through Saturday evening for IDZ423-426. OR...None.