textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Cold front with widespread showers, isolated thunderstorms, and gusty winds, coming in from the west late today and tonight.

- Breezy and cooler Monday, with showers continuing in the north, but becoming sunny in the south.

- Warmer and drier Tuesday through Thursday.

- Cooler and unsettled conditions possible on Saturday and Sunday.

SHORT TERM /Through Tuesday Night/

Issued 236 PM MDT SUN SEP 6 2026 An upper level trough continues to track across southern OR this afternoon. Showers and thunderstorms increase late this afternoon across eastern OR, with isolated showers and thunderstorms over the west central ID and Owyhee mountains. Showers will increase in coverage this evening as the upper level low tracks across southern ID early Monday morning. The precipitation will quickly taper off across eastern OR and the Snake Basin in southwest ID early Monday morning, with lingering showers over the central ID mountains through Monday afternoon. A convergence zone will set up in wake of the Wallowas late Monday afternoon keeping showers and thunderstorms north of McCall late into the evening. Drier and warmer conditions expected on Tuesday.

LONG TERM /Wednesday through Sunday/

Issued 236 PM MDT SUN SEP 6 2026 A warming trend will continue Wednesday through Thursday as the cool core upper level trough moves east with weak ridging. A trough from the Gulf of Alaska will move south along the BC coast into the Pacific NW by Saturday with cooler and windy conditions possible next weekend. Uncertainty remains elevated in the extended period, as tropical activity in the Pacific enhances the jet stream. Models do not handle the energy transfer well in these situations so expect lots of changes in the far extended period over the next week with all these tropical systems across the Pacific.

AVIATION /00Z Monday through Tuesday/

Issued 552 PM MDT SUN SEP 6 2026

Generally VFR. Cold front moving W to E, bringing numerous showers and isolated thunderstorms in far E Oregon and SW Idaho through late tonight. MVFR-IFR in local heavy rain, and gusty outflows with storms. Patchy fog/low stratus in mountain valleys and near KTWF/KJER overnight. Surface winds: W-NW 10-20 kt, gusts to 25-35 kt through this evening due to cold front. Areas of gusts up to 45 kt around KMUO-KTWF-KJER late this eve. Winds aloft at 10kft MSL: S-SW 15-25 kt, transitioning to W tonight.

KBOI...Generally VFR. Cold front bringing rain showers and a 20% chance of lightning before Mon/06Z. Brief MVFR possible during Mon/03Z-06Z window. Surface winds: NW 10-20 kt, gusts to 20-35 kt with cold front. Winds decreasing after Mon/04Z, becoming variable 5 kt overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.