textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Cool and dry conditions expected tonight through Sunday morning with patchy valley fog in the mountains.

- Light valley rain and mountain snow tomorrow evening in southeast Oregon, moving into southwest Idaho by Monday morning.

- Cooler and unsettled pattern continuing next week with snow levels potentially lowering to valley floors by the end of the week.

SHORT TERM /Through Monday Night/

Issued 207 PM MST SAT NOV 14 2026 The cold front has shifted to eastern Idaho this afternoon, with some lingering stratus cloud cover over the West Central/Boise Mountains. Trinity Mountain SNOTEL reported 7 inches of snow with this frontal passage and rainfall totals in the Snake River Valley ranged from 0.10-0.50 inches. Cool, dry, and breezy conditions will continue through most of the day on Sunday, with patchy fog tomorrow morning in higher elevation valleys. Another line of valley rain showers and mountain snow will move into southeast Oregon by midday on Sunday. Rainfall accumulations will range from 0.05-0.15 inches of rain with only a few inches of snow at higher peaks. This line will then gradually move into southwest Idaho overnight Sunday into Monday. Snow levels will stay between 5500-6500 feet MSL through Sunday and during the day on Monday, dropping off to 4500-5500 by Monday night. This will bring minor snow accumulations on Highway 55 and 21 on Monday night. Temperatures will linger a few degrees above normal today and tomorrow, still about ten degrees cooler than it has been this week.

LONG TERM /Tuesday through Saturday/

Issued 207 PM MST SAT NOV 14 2026 Weather in the long term is seasonally typical in terms of temperature, but with continual moisture supporting rounds of precipitation through next week. Tuesday, temperatures finally cool to near normal as a weakening longwave trough moves through the region. Down from 5-10 degrees above normal the day before, cooler air settles in for the week and drops snow levels to around 4-5 kft MSL. These higher snow levels will support a couple inches of snow in mountains and mountain valleys. In lower elevations, up to 0.2 inches of rainfall are possible. Precipitation heads east and the seasonal temperatures and cooler air mass move in. There is a very low chance of snow in lower elevations with this system, as snow levels aren't projected to fall to valley floors until Wednesday morning; well after precipitation has ended. Conditions briefly dry out Wednesday as a ridge warms up the cold morning temps back to normal that afternoon.

However, Wednesday evening, a closed Pacific low pressure system brings a more prolonged precipitation event. Precipitation with this system is most likely Wednesday evening through Thursday morning on the eastern side of the low. Guidance suggests the core of the low will track south of the forecast area, meaning as the peak moisture leaves the area, lingering wraparound moisture will continue precipitation through at least Friday morning with isolated coverage through Saturday morning. Again, snow levels around 4-5 kft MSL will support a couple inches of snow on smaller mountains and in mountain valleys. But, on the highest ridges and summits 6 to 10 inches of snow become possible as snow ratios rise in colder temperatures and orographic lift increases precipitation efficiency. Again, up to 0.2 inches of rainfall are possible in lower elevations. The colder air behind the closed low only drops temperatures by a few degrees, but enough for snow levels to approach valley floors by Saturday morning. With a 10% chance of precipitation in trailing showers there is again a low chance for valley snow. A ridge will begin to build between the exiting low and a strengthening closed low off the Pacific NW coast through the rest of the weekend.

AVIATION /00Z Sunday through Monday/

Issued 440 PM MST SAT NOV 14 2026 Generally VFR through Sunday morning with increasing mid- high clouds from the west. Patchy fog possible in mountain valleys of west-central Idaho Sunday morning. Showers develop over eastern Oregon after 15/15Z, affecting KBNO/KBKE, with a 30% chance of MVFR ceilings. Surface winds: S-SE 5-15 kt, with gusts to 25 kt on Sunday afternoon. Winds aloft at 10kft: SW 15-25 kt.

KBOI...VFR with BKN ceilings AOA 12 kft. Surface winds: SE 10-15kt. Gusts to 20 kt after 15/17Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.