textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Normal temps through Friday before another cooldown this weekend, conditions stay dry and breezy.

- Another round of precipitation Saturday night into Sunday with lower snow levels will bring snow to higher elevations.

SHORT TERM /Through Sunday Night/

Issued 226 PM MDT THU MAY 14 2026 Dry zonal flow aloft will keep conditions dry and breezy through Friday evening. Temperatures today and tomorrow will be near normal. Despite near normal temps, conditions remain very dry with afternoon minimum relative humidities in the 10s in lower elevations and 20s in higher elevations. Wind gusts in the afternoon will be 20-30 mph in the upper Snake Plain, ridges, and highlands. Gusts will be even stronger east of our area. Overnight winds in most areas calm to 10 mph or less, while gusts up to 25 mph persist on ridges and just along the Snake River.

Saturday morning, an approaching Alaskan low moves into the region. Clouds increase and showers develop north of the area early in the morning, moving into Eastern Oregon and Western Idaho later in the morning and early afternoon. As the core of the low moves through, precipitation moves from northwest to southeast and remains over mountains and highlands. The colder airmass coming with the low drop snow levels to 4000 ft MSL by midnight, potentially dropping even lower in the long term. This system will also see the return of very gusty winds beginning Saturday afternoon with gusts to 35-40 mph.

LONG TERM /Monday through Friday/

Issued 226 PM MDT THU MAY 14 2026 A cold-core low will center over the Northern Rockies on Sunday, continuing the well-below normal temperatures across E Oregon and SW Idaho. Snow levels will be low Sunday morning, around 3500-4500 feet MSL, before rising to 5000-6000 feet by Sunday afternoon. A chance of showers are forecast, mainly over the mountains, with light snow accumulations possible for the higher terrain. In addition, the unstable conditions due to the cold air aloft may allow isolated thunderstorms to develop Sunday afternoon.

Windy conditions will last through the rest of the weekend as the forecast area becomes positioned on the back side of the low. The low is expected to depart toward the east on Monday, allowing temperatures to rebound while winds and shower coverage decrease. Northwest flow aloft will keep a slight chance of showers across the northern zones through Tuesday, then warmer and drier near-zonal flow is anticipated for Wednesday and Thursday.

AVIATION /06Z Friday through Saturday/

Issued 1207 AM MDT FRI MAY 15 2026

VFR with mostly clear skies. Surface winds: light and variable this morning, then become W-NW 5-15 kt this afternoon. Winds aloft at 10kft MSL: W 20-30 kt.

KBOI...VFR. Surface winds: light and variable less than 5 kts becoming northwesterly 8 to 12 kts this afternoon.

Weekend Outlook: A cold frontal passage Sat-Sun will bring scattered rain/snow showers over mountains and gusty W-NW winds throughout the weekend. Localized MVFR-IFR conditions and mountain obscuration in showers. Snow levels will drop from 5.5-6.5kft Saturday to the 3.5- 5kft Sunday. Surface winds: W-NW 10-20 kt Sat, with gusts 25-35 kt. Stronger winds Sunday at NW 15-25 kt with gusts 30-40 kt over most areas.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.