textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Breezy and cool today, with lingering mountain showers in northeast OR and central ID.

- Slight warming and drying trend Tuesday and Wednesday, with light winds.

- Another push of low pressure will bring precipitation to higher terrain and south central Idaho by the middle of this week.

SHORT TERM /Through Wednesday Night/

Issued 307 AM MDT MON SEP 14 2026 Scattered low clouds and patchy valley fog will develop this morning, primarily in high terrain, but clearing will occur by late morning into the early afternoon. A deep low pressure system will move northeast of the region today, keeping cool temperatures and breezy westerly winds over the region with some lingering mountain showers across northeast Oregon and central Idaho. A longwave trough will keep slightly below normal temperatures tomorrow, but southwest flow aloft will bring a slight warming and drying trend by Wednesday. Another low pressure system will dive into western Oregon late Wednesday, with southerly flow allowing for some monsoonal moisture to move northward over south central Idaho. This low will then track to the east over our region on Thursday, bringing a slight chance of showers and cooler temperatures. Isolated thunderstorms are possible as well, especially Thursday afternoon. Light and primarily terrain driven winds will dominate the short term period, with slightly increasing southerly winds on Thursday.

LONG TERM /Thursday through Monday/

Issued 307 AM MDT MON SEP 14 2026 Cool and unsettled conditions will continue on Friday, with showers lingering over high terrain. Precipitation accumulations look to be minimal and isolated to higher elevations in Baker County, OR and the West Central Mountains. A short lived pattern shift will then occur by the weekend. Model solutions have come into alignment over the ridge of high pressure developing over the Intermountain West by Saturday. This will bring above normal temperatures and dry conditions through Monday, but another trough looks to move onshore by the middle of next week.

AVIATION /12Z Monday through Tuesday/

Issued 612 AM MDT MON SEP 14 2026

Generally VFR. Scattered low stratus across Baker County and the west-central Idaho mountains creating mountain obscuration, mixing out by early afternoon. Patchy valley fog/mist this morning near KBKE, KMYL, and KBNO. Surface winds: SW-NW 5-15 kt. Winds aloft at 10kft MSL: W to NW 15-35 kt.

KBOI...VFR. Mid level clouds lowering to 3500-5000 ft AGL between Mon/12Z-15Z, then clearing by the afternoon. Surface winds: NW 4-8 kt becoming variable less than 5 kt this evening, then ESE 4-8 kt by Tues/10Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.