textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Mostly sunny and warm today.

- Cold front and gusty winds late today and this evening, followed by breezy and slightly cooler weather Friday, then warmer again Saturday.

- Much stronger cold front late Saturday and Saturday night with wind gusts 40 to 50 mph in southern areas, and widespread showers and scattered thunderstorms in the north.

- Windy and much cooler Sunday, with showers continuing in the north.

- Warming and drying Monday and beyond.

SHORT TERM /Through Saturday Night/

Issued 201 AM MDT THU SEP 10 2026 Latest satellite imagery shows mid and high level clouds in nrn California and out into the Pacific. Models spread these clouds across our southern zones today but leave northern zones sunny. A dry cold front from the north will push a band of mid and high clouds across our northern zones tonight, merging with the southern clouds in eastern Idaho late tonight. Today will therefore be "mostly sunny". The approaching cold front will increase west winds to 15-25 mph in southern areas late today and this evening, but after it passes Friday will be only 5 to 10 degrees cooler than today mainly in the north.

The big story is the stronger cold front and deep upper low still forecast in our CWA late Saturday through Sunday night. Latest models delay arrival of the cold front until late Saturday afternoon in eastern OR and Saturday evening in western ID. This delay will allow Saturday to get about 5 degrees warmer than forecast yesterday morning. Pre-frontal southwest winds will still increase in southeast OR Saturday afternoon, with fire danger also increasing due to the combination of wind and low humidity. The deep upper low off the OR coast is forecast inland across OR Saturday night, then northeastward across nrn ID into MT Sunday, also slower than forecast yesterday. As a result, maximum frontal wind gusts should be slightly less but still at least 40 mph in all southern zones. A Wind Advisory will be considered for those areas in the day forecast. The rest of the previous forecast is still there: widespread showers and scattered thunderstorms with locally heavy rain Saturday night in northern areas, and strong gusty winds in southwestern ID Saturday evening, and south-central ID later Saturday night. Due to the slower movement of the upper low showers will continue all day Sunday in the north (where the main moisture will be), with gradual clearing in the south. Sunday night will continue the clearing trend from west to east, and will be colder, with areas of fog in northern valleys overnight and Monday morning. Then sunny and warmer Monday.

LONG TERM /Sunday through Thursday/

Issued 201 AM MDT THU SEP 10 2026 A following upper trough will bring only some clouds from the north to the central ID mountains Monday night while leaving other zones mostly clear. The next upper trough will split a weak closed low off the OR coast Wednesday, again leaving our CWA generally clear but also warming into Thursday and beyond.

AVIATION /12Z Thursday through Friday/

Issued 525 AM MDT THU SEP 10 2026 VFR with high clouds south and clear skies north. Cold front and broken clouds above 15kft MSL will spread southward into central ID (including KMYL) after 03Z Friday. Surface winds: Variable less than 10 kt through 18Z, becoming SW-NW 10-15 kt after 18Z. Gusts to 30 kt after 20Z Thursday in the Magic Valley and south of the Snake Plain. Winds aloft at 10kft MSL: W 15-20 kt this morning, increasing to 25-30 kt after 18Z.

KBOI...VFR with clear skies. Surface winds: SE 5-8 kt until 15Z, becoming NW around 10 kt by 20Z.

Weekend Outlook...VFR Saturday with increasing SW surface wind in OR Saturday afternoon. Strong Pacific cold front Saturday evening. MVFR conditions and mountain obscuration with widespread showers and scattered thunderstorms mainly in Baker County/OR and north of the Snake Basin in ID. W surface wind 20-30 kt with gusts 40 kt Saturday evening in se OR and sw ID from the Snake Basin south. Showers and MVFR conditions continuing in central ID Sunday, but improving to VFR in se OR Sunday afternoon and in se ID Sunday evening.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.