textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Breezy conditions this afternoon and evening ahead of a cold front, turning much cooler on Saturday.

- Active pattern bringing cooler conditions and precipitation chances Saturday through Tuesday. Snow showers above 6000-8000 feet this weekend.

- Significant rainfall possible in southcentral and southeast Idaho late Saturday through Tuesday.

SHORT TERM /Through Sunday Night/

Issued 247 PM MDT FRI OCT 9 2026 Columbia and Alberta will move south into northern CA by Sunday with a long stream of moisture connected to the remnants of Rachel. Most of the moisture will stay east of our area though. The trough will bring a strong cold front to the area tonight with much cooler conditions on Saturday and Sunday. Precipitation over eastern OR will generally be limited with this system, with the best chance and heaviest precipitation coming over the Boise Mountains, and eastern Magic Valley through Sunday. Snow levels fall to 5000 to 6000 feet in eastern OR, and north of McCall ID, but precipitation will be limited. Snow levels in ID will be much higher in the warm sector of the system, with 7000 to 8000 feet over the central ID mountains.

LONG TERM /Monday through Friday/

Issued 247 PM MDT FRI OCT 9 2026 conditions will persist into the start of the coming week. This will be thanks to the upper trough/low that brought our area the cooldown. While uncertainty remains on the placement of the low that closes off, ensemble guidance remains pretty locked in on troughing remaining over our area. The best chances for precipitation will come in southwest Idaho, where south/southwesterly flow aloft will continue to transport the remains of Tropical Storm Rachel. While the best remnant moisture will likely be to our south and east, The western Magic Valley has a 55-65% chance of receiving at least a tenth of an inch of additional rain fall from 6am MDT Monday through 6am Tuesday. Precipitation chances will remain elevated through Tuesday night (15-35%) across the western Magic Valley, Boise Mountains, and Southern Idaho Highlands as the low move off to the east. While there is some uncertainty in the exact track of the low as it moves off east, the aforementioned locations have the better odds of getting clipped by some of the wrap-around precipitation. Thanks to the southerly flow aloft, higher snow levels will limit any dusting of snow to above 7000 feet, with little accumulation anticipated.

A warming and drying trend will set in beyond Tuesday, with the shortwave mentioned in previous discussions having trended north out of our area. In its wake, ridging will set in over the west coast mid-week, shifting to the Great Basin by the end of the week. Temperatures at the start of the coming week will be 5-10 degrees below normal, trending upwards to be leaning above normal by Friday.

AVIATION /00Z Saturday through Sunday/

Issued 516 PM MDT FRI OCT 9 2026

Generally VFR with increasing clouds this evening. Smoke from prescribed burns resulting in localized visibility reductions, mainly near KMYL. Virga/isolated showers this eve and continuing through Sat/PM. Gusts up to 45 kt with showers this evening. Surface winds: SW-NW 5-15 kt with gusts up to 30 kt in E-Oregon and higher terrain. Becoming W-NW 10-20 kt with gusts 20-35 kt behind a cold front this evening/overnight. Gusts tapering off early AM/Sat, then 20-25 kt returning Sat afternoon. Winds aloft at 10 kft MSL: SW 15-35 kt.

KBOI...VFR with increasing high clouds this evening. Virga/isolated showers passing through the Treasure Valley this evening through Sat/AM, although a low chance (<10%) of rain at terminal. Surface winds: W-NW 5-15 kt, period of gusts to 20-25 kt overnight associated with a cold front. Gusts returning Sat afternoon.

Weekend Outlook...Isolated rain showers, with high elevation snow (central ID), Saturday afternoon through Sunday. Then, broad area of precipitation expanding from ID-NV border through s-central and central Idaho Sunday. Precip may become heavy at times. Snow levels 6-8kft MSL across SW Idaho, 4-6kft for SE Oregon. Mountains obscured at times with MVFR/IFR conditions possible in heavier precip and in mtn snow. Surface winds: W-N 5-15 kt with gusts 20-30 kt Sat/Sun.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning until 8 PM MDT this evening for IDZ423-426. OR...None.