textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- A strong cold front will bring gusty winds and cooler temperatures area-wide today, with isolated showers for the north.

- Temperatures will average 10 degrees below normal on Saturday.

- A weak low pressure system will support shower chances near the NV border and central Idaho Sunday.

- Seasonable temperatures returning next week.

SHORT TERM /Through Sunday Night/

Issued 303 AM MDT FRI SEP 25 2026 A pronounced low pressure system is currently moving through western Washington and Oregon early this morning and will continue into eastern Oregon and Idaho later today. The accompanying cold front will arrive in east Oregon by mid morning, and into southwest and central Idaho by this afternoon and evening. Rain showers will move along the front, remaining limited to northeast OR and w-central ID. However, chances for measurable rainfall are relatively low (10-25%). Winds will transition from southeast-southwest to west-northwest with the frontal passage, with gusts increasing to 25-35 mph across the area. Pockets of 40 mph can be expected in portions of the Upper Treasure Valley and the higher terrain of southwest/central Idaho. Max temperatures will cool as much as 15-20 degrees in the Oregon zones today compared to yesterday. Due to the later arrival of the front, the Idaho zones will have 5-15 degrees of cooling today, then additional 5-15 degrees of cooling for Saturday. Winds will gradually taper off tonight as the trough exits toward the northeast, with drier, cool, and mostly cloudy weather prevailing on Saturday. A weak, elongated trough will then approach on Sunday and generate a slight chance of showers near the Nevada border and over central Idaho through Sunday night.

LONG TERM /Monday through Friday/

Issued 303 AM MDT FRI SEP 25 2026 The aforementioned trough will exit Monday, allowing temperatures to rebound to near-normal values through much of the week as westerly flow develops aloft. Benign conditions will proceed through at least Thursday as the storm track remains north of the area. Long range ensemble members are signaling another cool-down toward the end of the week as 1000-500mb thicknesses gradually lower. However, guidance continues to keep moisture out of the forecast area through the extended period.

AVIATION /12Z Friday through Saturday/

Issued 550 AM MDT FRI SEP 25 2026

VFR. Cold front will move from W to E today, bringing gusty winds area-wide. Isolated showers and lower ceilings will pass through northeast OR and w-central ID late morning through evening, with light rain or virga for KBNO/KBKE/KMYL. Surface winds: S-SE 5-15 kt with 15-25 kt gusts. Shifting to SW-NW 10-20 kt with 20-35 kt gusts with front. Winds aloft at 10kft MSL: SW 20-40 kt, gradually decreasing by this evening. Pockets of LLWS through mid morning.

KBOI...VFR. Surface winds: S-SE 7-14 kt with occasional gusts near 20 kt through morning. Cold front will move through early afternoon, shifting winds to NW 12-20 kt with 25-30 kt gusts.

Weekend Outlook...VFR with high/mid level ceilings Saturday and Sunday. Isolated showers near NV border and over central ID mtns Sunday. Surface winds: NW 5-15 kt Saturday, and NW 5-20 kt Sunday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.