textproduct: Boise

KEY MESSAGES

- Continued warm and dry conditions Friday.

- Windy conditions this evening with a slight chance of thunderstorms along the front tonight with valley rain and high elevation snow.

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

SHORT TERM /Through Sunday Night/

A strong cold front will move across the area this afternoon and evening bringing showers, mountain snow, and a slight chance of thunderstorms along the cold front. Strong prefrontal winds this afternoon, with values up to 50 kts in southern Twin Falls County, where a wind advisory has been issued. These winds will continue through this evening ahead of the cold front. This system will be quick-hitting and weaken as it moves inland, with precipitation ending from the west late Friday night through early Saturday morning. Rain amounts of 0.10-0.25 inch will be common across southeast Oregon and the lower elevations of southwest Idaho, with 0.30-0.60 inch across the mountains. Snow levels will be above 7000 feet initially and only fall to 5500-6500 feet behind the cold front, limiting accumulating snow to higher mountains. Winds will decrease behind the front to 5-15 mph on Saturday, except gusts 15-30 mph will persist in the Magic Valley. Highs Saturday will be 10-15 degrees cooler in most areas, but still several degrees above normal. An upper level ridge will begin building overhead on Saturday as the system moves east with partly to mostly sunny skies. The next system approaches the area on Sunday with showers developing in eastern OR by Sunday morning. The system will be slow to move across eastern OR, reaching southwest Idaho by late Sunday evening into Monday morning. Light precipitation amounts with this system, generally under 0.25 inch.

LONG TERM /Monday through Friday/

An upper level trough will bring another push of cool and wet weather on Monday and Tuesday. Breezy winds, valley rain, and mountain snow will begin late Monday into early Tuesday. Snow levels will start at 5500-6500 feet, dropping 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 will continue as cold air stays firmly in place through the long term period. Model agreement remains high through Friday with a deeper upper level low bringing much colder air and another hit of precipitation to the region late Wednesday into early Friday. Some model disagreement exists with how low snow levels will drop, with about three quarters of the GFS/ECMWF ensemble solutions favoring snow levels dropping to valley floors by Thursday night. This would bring the first measurable snowfall to the Treasure Valley for the season. Considerable variability exists in the high temperature forecast, with Thursday and Friday highs ranging from the upper 30s to the upper 40s. Current forecast favors the warmer range of these outcomes, with snow levels only dropping to 3000-4000 feet MSL and rain staying the dominant precipitation type for most lower elevation valleys through Friday. Precipitation will linger over the region through Friday morning, tapering off as high pressure begins to build back into the region by the weekend.

AVIATION /18Z Friday through Saturday/

Issued 1038 AM MST FRI NOV 13 2026

VFR for most of today. A cold front will bring low VFR/MVFR conditions in rain and IFR/LIFR conditions in high mountain snow this evening through tomorrow morning. Lower elevation terminals will see a 30% chance of thunder with the frontal passage late this evening. Snow level: 6.5-7.5kft MSL Fri/PM lowering to 5.5-6.5kft MSL by Sat/AM. Surface winds: SE-SW 10-25 kt with gusts 25-40kt, strongest in south- central Oregon and high terrain. Mountain wave activity possible Friday, particularly near KTWF and the Owyhee Mountains. Winds aloft at 10kft MSL: Southerly 25-40 kt shifting to W 20-35 kt after Sat/06Z.

KBOI...VFR. Rain showers arrive this evening after Sat/02Z ahead of cold front. Rain intensity will increase between Sat/04Z-07Z, bringing a 30% chance of thunderstorms. MVFR conditions early this 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 between Sat/04Z-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...Wind Advisory until 11 PM MST this evening for IDZ030. OR...None.