textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- A cold frontal passage Saturday will bring cooler temperatures, mountain showers, and gusty W-NW winds through the evening.

- Unseasonable warmth returning mid next week.

SHORT TERM /Through Sunday Night/

Issued 220 PM MDT FRI MAR 20 2026 The unseasonably strong upper level ridge that has brought record breaking heat to the region will begin to break down tonight. We remain on track to tie or break the all-time March record High Temperature for Boise of 82 degrees set on March 26, 1877. While tonight will remain mild, the approach of a cold front from the Pacific Northwest will lead to an increase in mid and high level cloud cover, particularly across southeast Oregon and central Idaho.

On Saturday, the cold front will sweep across southeast Oregon and southwest Idaho. This will bring a significant change in the weather pattern, with temperatures dropping 10 to 20 degrees compared to Friday. Breezy west to northwest winds will develop behind the front Saturday afternoon, with gusts of 20 to 35 mph possible. While the moisture associated with this system is limited, there is a chance (20%) for showers over the mountains of Baker County and west central Idaho. Snow levels will be between 6000-7000 feet MSL.

By Sunday, dry northwest flow aloft will settle over the area. This will result in a cool but pleasant day with plenty of sunshine. Temperatures on Sunday will be much closer to seasonal normals. Winds will be lighter than Saturday, though typical afternoon gusts of 15 to 25 mph can still be expected. Clear and cool conditions will persist through Sunday night as the region remains between weather systems.

LONG TERM /Monday through Friday/

Issued 220 PM MDT FRI MAR 20 2026 Dry conditions will prevail to start the work week, with warming temperatures as heights rise ahead of the next system. Temperatures on Monday will be 10-20 degrees above normal, then challenging record highs come Tuesday. Confidence continues to increase on a cold front impacting our area mid-week next week, with a trough out of British Columbia digging across the Pacific Northwest. However, uncertainty still remains on the exact timing of the front. A Wednesday arrival would drop temperatures closer to normal Wednesday, whereas a Thursday arrival would allow for an extra day of above normal temperatures before dropping near normal Thursday. Either way, temperatures behind the cold front will be near normal for the time of year. The best chance of precipitation (20-40%) associated with this system will come Wednesday, mainly across higher terrain. Thursday will feature seasonable temperatures with precipitation tapering off. Beyond Thursday, ensembles generally favor ridging building back in across the area. This supports warming temperatures and dry conditions through the weekend.

AVIATION /06Z Saturday through Sunday/

Issued 1136 PM MDT FRI MAR 20 2026

VFR overnight. A cold front will move NW-SE after Sat/14Z, bringing isolated rain showers near KBKE/KMYL. Potential for brief MVFR and mtn obscuration in showers. Surface winds: variable up to 10 kt. Then, W-NW 5-15 kt with gusts to 15-25 kt Sat AM, increasing to 10- 20 kt with gusts 20-30 kt Sat PM. Winds aloft at 10 kft MSL: W-SW 20- 40 kt.

KBOI...VFR. Surface winds: SE or variable less than 10 kt. Becoming W-NW 8-18 kt after Sat/16Z with cold front. Afternoon gusts around 25 kt.

Weekend Outlook...Becoming VFR Saturday night and Sunday. Surface winds: NW or variable 5-15 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.