textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Continued warm and dry Friday with record high temperatures possible.

- Windy conditions on Friday ahead of a cold front.

- Valley rain and mountain snow along a cold front Friday night into Saturday morning.

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

SHORT TERM /Through Saturday Night/

Issued 248 PM MST THU NOV 12 2026 A strong upper level ridge remains centered near the Continental Divide while a deep upper level low in the Gulf of Alaska approaches the coast. This will keep southerly flow in place today, with near-record warm temperatures and dry conditions. Skies will be partly to mostly sunny with passing high clouds. Winds slowly increase as the low begins to move onshore late Friday. Expect gusts 35-50 mph across open areas of southeast Oregon and far southwest Idaho, strongest in remote areas of southern/western Harney County Oregon. Elsewhere, expect gusts 20-40 mph.

A cold front will enter central Oregon Friday afternoon and move east across our area Friday night, bringing widespread precipitation along the 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 0.05-0.25 inch will be common across southeast Oregon and the lower elevations of southwest Idaho, with 0.20-0.50 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.

LONG TERM /Sunday through Thursday/

Issued 248 PM MST THU NOV 12 2026 The next low pressure system will be moving into the area starting Sunday. On Sunday, precipitation chances will be limited to eastern Oregon before spreading into SW Idaho by Sunday evening. The trough will hold together enough for a 50-70% chance of light precipitation late Sunday through Tuesday. A cold front will slowly move through the area west-to- east, starting early Monday. Breezy prefrontal southwesterly surface winds will warm temperatures by a few degrees Sunday compared to Saturday, switching to cooler northwesterly flow Monday and Tuesday. Snow levels will fall from 5500-6500 feet Sunday night to 4000-6000 feet by Tuesday, lowest across eastern Oregon. A brief dry period is expected early Wednesday morning before the next system moves in. This deep upper-level low will move overhead from mid to late week, bringing colder air than previous systems. Uncertainty currently surrounds just how cool the temperature will get and the extent of the accompanying precipitation. Regardless, precipitation chances are currently forecast at 30-50% late Wednesday through Thursday, with temperatures favored to cool a few more degrees and snow levels around 3500-5000 feet.

AVIATION /06Z Friday through Saturday/

Issued 1029 PM MST THU NOV 12 2026

VFR and high clouds. A cold front will bring rain and high mountain snow Friday evening into Saturday morning. Low VFR-MVFR in rain, IFR-LIFR and mountain obscuration in snow. Snow level: 6500-7500 ft MSL Fri night. Surface winds: E-S 5-15 kt overnight. Then, SE-SW 10-25 kt with gusts 25-45 kt due to approaching cold front, strongest in south-central Oregon. Mountain wave activity possible Friday, particularly near/south of KTWF and the Owyhee Mountains. Winds aloft at 10kft MSL: southerly 25-40 kt. Areas of LLWS in Snake Plain from KONO to KTWF/KJER through overnight hours.

KBOI...VFR. Rain showers arrive around Sat/02Z ahead of cold front. Rain intensity will increase between Sat/03Z-06Z, bringing a 45% chance of MVFR conditions during this window. Surface winds: SE 8-15 kt, increasing to SE 15-20 kt with gusts to 25-35 kt late Fri morning through evening. Winds will briefly shift to SW-W 5-15 kt with gusts 15-25 kt between Sat/03Z-06Z. Becoming variable up to 10 kt thereafter.

Weekend Outlook...Lingering MVFR-LIFR mountain showers over central ID Saturday morning, with isolated showers elsewhere. Snow levels: 6000-6500 ft MSL Sat/AM. Becoming drier with decreasing low and mid clouds late Saturday through early Sunday, then rain increasing across SE Oregon Sunday aftn/eve. 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.