textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Above normal temperatures today and tomorrow.

- A weak cold front brings a slight chance of showers to Baker County and the west central Idaho mountains on Sunday.

- Significantly above normal temperatures develop next week, peaking Wednesday around 15 degrees above normal with potential record highs.

SHORT TERM /Through Sunday Night/

Issued 321 AM MST FRI NOV 6 2026 Weak, zonal flow aloft will develop over the area today into tomorrow, keeping quiet and dry weather through Saturday. This brief pattern will be created by a low amplitude upper- level ridge over the Intermountain West, bringing warmer than average temperatures. Temperatures today will be near- to slightly above-average, while Saturday will see temperatures 5-15 degrees above normal. Overnight valley inversions and patchy early morning fog in sheltered basins are common under this pattern. Late Saturday and Sunday, a weak shortwave and accompanying cold front will track across the Pacific Northwest. Breezy prefrontal winds are expected for most areas, except sheltered mountain valleys, Saturday night into Sunday morning. Moisture and dynamics remain quite limited with this boundary, limiting precipitation chances to 5-10% in northern Baker County and the west central Idaho mountains. The remainder of southwest Idaho and southeast Oregon will stay dry, with little more than passing mid- and high-level clouds. A slight cool down from Saturday to Sunday is expected as well.

LONG TERM /Monday through Friday/

Issued 321 AM MST FRI NOV 6 2026 Southwesterly flow aloft will still be overhead Monday as troughing in the Gulf of Alaska begins to establish itself. This longwave troughing pattern will become largely stationary, contending with persistent upper- level ridging over the southwest CONUS. Flow aloft through the week will be out of the south/southwest, however, most of the moisture being brought north will stay west and north of the area. This combination will bring mostly dry and anomalously warm conditions as the ridge builds through the mid-week. Temperatures will climb rapidly from Monday onward. By Wednesday, high temperatures are projected to peak in the mid to upper 60s for lower elevation valleys, which is roughly 15 degrees above seasonal normals. Several locations, including the Treasure Valley, could approach or exceed daily record highs. Dry and tranquil conditions will persist across the forecast area through mid-week under this strong ridge. Model guidance begins to hint at unsettled weather approaching late in the week / weekend as the offshore trough moves slightly eastward and the ridge weakens.

AVIATION /12Z Friday through Saturday/

Issued 421 AM MST FRI NOV 6 2026

Mostly VFR, though IFR fog/low stratus is again possible in KBKE/KBNO/KMYL, with a low chance in the lower Treasure Valley. Surface winds: variable 5-10 kt. Winds aloft at 10kft MSL: NW 5-15 kt.

KBOI...VFR, possible fog development in the lower Treasure Valley is unlikely to impact the site. Surface winds: SE 4-8 kt.

Weekend Outlook...Mainly VFR. Isolated showers across the north on Sunday. Patchy fog each night and early morning across sheltered basins. Surface winds E-S 5-15 kt with gusts to 20-30 kt Saturday and Sunday. Wind direction shift to W-NW Sunday afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.