textproduct: Boise

KEY MESSAGES

- Drier and cooler conditions Saturday.

- Second low pressure system returning rain and mountain snow Sunday through Monday.

- 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/

As the active low pressure system steers eastward out of our area, Saturday will see remnant showers and light mountain snow taper off over the west-central ID mountains and Magic Valley through the afternoon. An upper level ridge will begin building overhead on Saturday with partly to mostly sunny skies. Saturday will be 10-15 degrees cooler in most areas, but still several degrees above normal. The dry break will continue through late Saturday, before the next Pacific trough system approaches the area with showers developing in eastern OR by Sunday morning.

Except for eastern OR coming under the trough's arrival, most areas will be dry and 5-10 degrees warmer than normal on Sunday. A slow-moving band of precipitation will gradually steer eastward across eastern OR, before reaching southwest Idaho by late Sunday evening into Monday morning. This system will slowly trek across southwest ID throughout Monday, returning valley rain showers and light mountain snow showers. Valleys will generally see relatively lighter rain accumulations at around 0.25 inches total. High terrain areas over the central ID mountains and the ID/NV border will see the bulk of precipitation from this system on Monday. Snow levels will mostly hang in the 5500-7000 ft MSL range through most of Monday, before gradually dropping down into the 4500-5500 ft range by late Monday. As such, minor snow accumulations of around 1 inches are likely over the central ID mountains and ID/NV border through late Monday.

LONG TERM /Tuesday through Saturday/

The upper-level trough digging across our area through Tuesday will return a cooling pattern for the remainder of the week. Valley rain and mountain snow showers will continue on the southwest ID side through Tuesday morning as it tapers off east by the afternoon. Snow levels will drop to 4500-5500 feet by Tuesday morning. This will bring minor snow accumulation to the Central Idaho Mountains and the Idaho-Nevada border, with Tuesday night snowfall totals between 1 to 3 inches. A ridge of high pressure will briefly build into the region on Wednesday, bringing mostly dry conditions.

Near to slightly below normal temperatures are expected to remain in place throughout the long-term period as active patterns continue. There is generally strong guidance agreement on a deep Pacific upper low digging into the Pacific Northwest and Great Basin regions Wednesday through Friday. There is still slight guidance uncertainty over the upper low's exact movement pattern going into Friday, but a 50-80% chance of precipitation remains for Wednesday through Friday. This active troughing pattern will bring a further cooldown. Considerable guidance uncertainty remains for snow level trends from midweek to the end of the week. There is potential for snow levels to drop down to valley floors Wednesday through Friday, bringing the possibility of light snow showers over valleys. For now, the current long-range forecast has rain and/or rain/snow mix staying the dominant precipitation type for most lower elevation valleys through Friday. The low pressure system will steer eastward out of the region by early Saturday, with an amplifying Pacific ridge building immediately behind it. Saturday will see partly clearing skies and drier conditions.

AVIATION /06Z Saturday through Sunday/

Issued 1133 PM MST FRI NOV 13 2026 A cold frontal passage will continue low VFR/MVFR conditions in rain and IFR/LIFR conditions in high mountain snow overnight through Saturday morning. Snow levels: 4.5-6kft MSL. Surface winds: W-NW 10- 25 kt with gusts 20-30kt, strongest behind the front. Winds aloft at 10kft MSL: W 20-35 kt.

KBOI...Moderate rain showers continuing through early morning. MVFR conditions expected overnight into early morning with lowering ceilings, improving back to VFR by sunrise. Surface winds: SE 15-20 kt with gusts to 25-35 kt through evening. Winds will briefly shift to SW-W 5-15 kt with gusts 15-25 kt through around 07Z. Becoming variable up to 10 kt thereafter.

Weekend Outlook...Becoming drier with decreasing low and mid clouds late Saturday through early Sunday, then rain increasing across SE Oregon Sunday PM. Surface winds: On Saturday, SW-NW 5-15 kt with gusts 15-30 kt, strongest in the Magic Valley. On Sunday, E-S 5-15 kt with gusts 20-30 kt in portions of the Snake Plain and SE Oregon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.