textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- A chance of light precipitation on Saturday, then drier and warmer on Sunday.

- A Canadian trough will bring cooler temperatures, mountain showers, and strong gusty winds Monday through Friday.

SHORT TERM /Through Sunday Night/

Issued 211 PM MST FRI MAR 6 2026 An upper ridge will build in from the coast over the weekend. Weak warm advection coupled with high precipitable water content will bring increased cloud cover and a chance of precipitation from late tonight into Saturday. Amounts will be light with spotty coverage at the lower elevations. A cluster of high resolution models is showing light precipitation extending further southward, so have increased the probability for measurable rain to 15-30% across the lower Snake Plain west of Mountain Home and SE Oregon down to the NV border. A low chance of showers lingers over the w-central ID mtns on Sunday, north of McCall to Yellow Pine. Snow levels will start at mtn valley floors tonight into Saturday morning where up to an inch is possible. After some morning fog, dry and notably warmer temperatures will set up on Sunday as the ridge moves overhead. Warmer spots will see highs in the lower 60s, with the entire region reaching around 10F degrees above normal.

LONG TERM /Monday through Friday/

Issued 211 PM MST FRI MAR 6 2026 Zonal flow aloft, directed by a Canadian trough, will continue to bring gusty winds, cooler temperatures, and mountain precipitation to the region for most of the period. The primary frontal passage will occur late Monday into Tuesday, with the best chance of precipitation over high terrain in northeast Oregon and southwest Idaho (30-50% chance). Westerly winds will increase across the region, especially Tuesday into Thursday.

A brief period of dry conditions will occur early Wednesday, with uncertainty in the pattern by midweek. There are two main scenarios that are represented by the range of model solutions. The first keeps the bulk of the moisture and colder air north, with the Pacific High building in over the region. This solution would keep the region mainly dry with above normal temperatures. The second solution deepens the Canadian trough over the region, bringing cooler temperatures and widespread precipitation much further into our region. Deterministic Canadian and GFS models generally favor the first solution with the warmer and drier conditions, while the AI GFS and AI ECMWF favor the second solution, deepening the trough over the region.

Current forecasts strike a middle ground between these two solutions, with warm temperatures and dry conditions anticipated over the Snake River Valley and the ID-NV border. However, the forecast also introduces increased precipitation (20-40% chance) over high terrain in northeast Oregon and southwest Idaho on Thursday-Friday.

AVIATION /00Z Saturday through Sunday/

Issued 510 PM MST FRI MAR 6 2026 Generally VFR this evening with increasing mid-high cloud coverage. Localized MVFR/IFR conditions in light showers overnight through Saturday morning, with snow levels around 4-5 kft MSL tonight increasing to 6-8 kft MSL late Saturday morning. Surface winds: W-NW 10-20 kt with gusts up to 25 kt for lower Treasure Valley and up to 35 kt from KMUO to KTWF, tapering off to variable less than 10 kt overnight. Winds aloft at 10kft MSL: NW-N 15-30 kt.

KBOI...VFR. Light rain showers early to late Sat morning, creating low VFR-MVFR ceilings. Surface winds: NW 10-15 kt with afternoon gusts up to 25 kt, decreasing back to NW 5-10 kt overnight.

Weekend Outlook...LIFR-IFR conditions in patchy valley fog each morning. Low VFR to IFR in rain/snow and low clouds Saturday. Mtn obscuration. Mainly VFR and dry Sunday, except isolated showers over the northern mountains. Snow levels: 4-5kft MSL Sat AM rising to 6- 8kft MSL by Sat PM. Surface winds: SW-NW 5-15 kt, with afternoon gusts to 20 kt mainly over KMUO-KTWF-KJER areas.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.