textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Light rain and high mountain snow showers tonight. Mostly cloudy but dry in southern areas.

- Continued above normal temperatures through the week, warmest mid to late week with record highs possible.

- Chance of precipitation returns Friday night with cooler and wetter conditions developing over the weekend into next week.

SHORT TERM /Through Wednesday Night/

Issued 326 AM MST MON NOV 9 2026 Mild southwest flow will continue today ahead of an upper level trough that will move across the area tonight. This system will bring a 20-50% chance of showers to the lower elevations north and west of a Boise to Rome Oregon line and a 60-80% chance across the mountains of northeast Oregon and west-central Idaho, while rain chances to the south will be lower. Precipitation amounts will generally be less than 0.10 inch, but up to 0.25 inch is possible in the mountains. Snow levels will remain high limiting any accumulation to peaks above 7500-8000 feet MSL. Dry conditions will return Tuesday and Wednesday the system moves east and upper level ridging builds across the region. Temperatures today and Tuesday will be similar to Sunday with highs 10-15 degrees above normal, then rise to 15-20 degrees above normal on Wednesday. This will place max temperatures near record highs for the date, with Boise forecast to reach 69F compared to a daily record of 71F. Winds will be breezy from the south to southeast today with gusts 15-30 mph. Winds will subside Tuesday before picking back up on Wednesday as another system approaches the Pacific Northwest.

LONG TERM /Thursday through Monday/

Issued 326 AM MST MON NOV 9 2026 Mild southerly flow will continue on Thursday and Friday as a highly amplified ridge remains centered to our east. An initial upper level trough will split as it approaches the coast, but a deeper low is then expected to move inland late Friday into the weekend. Temperatures will be near record highs through late week with dry and breezy to windy conditions. Gusts 35-50 mph are possible on Friday across the open terrain of southeast Oregon with gusts 20-40 mph elsewhere.

Precipitation may arrive as early as Friday night as a shortwave trough rotates inland, but uncertainty remains in how far south this system will reach. A 20-50% chance of precipitation will develop Friday night and Saturday across east-central Oregon and the southwest Idaho mountains, with precipitation chances in the higher terrain aided by moist southwest flow aloft. Precipitation chances will remain less than 20% elsewhere. High snow levels around 6500-7500 feet will limit snow accumulation to the peaks. Another shortwave trough will push inland Sunday and Monday, increasing the chance of precipitation to 30-60% in all areas with the highest chances in the mountains. Snow levels should remain high through Sunday, then lower by Monday to 4000-5500 feet as colder air arrives with the trough. This should also cool high temperatures to near normal on Monday. Winds will be gusty through early Sunday, then taper off slightly late Sunday and Monday as the trough moves through.

AVIATION /12Z Monday through Tuesday/

Issued 458 AM MST MON NOV 9 2026 Mainly VFR. Mid to high clouds moving overhead through the day. Showers mainly north/west of a KREO-KBOI-KSUN line late this afternoon into tonight. Ceilings lowering to low VFR in showers, with MVFR/IFR possible over the mountains. Snow levels 7500-8500 ft MSL. Surface winds: SE-SW 5-15 kt. Gusts to 25 kt across higher terrain. Winds aloft at 10kft MSL: SW 15-30 kt.

KBOI...VFR. Surface winds: SE 5-10 kt this morning, then variable less than 8 kt this afternoon. A 10% chance of showers late this evening.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.