Area Forecast Discussion

UPDATE

Updated aviation discussion and Key Messages.

KEY MESSAGES

- Cold front this morning, then breezy and cool through Sunday. - High temperatures Sunday will be 10 degrees below normal with rain and snow showers possible in the west-central Idaho mountains.

- Showers Tuesday and Wednesday will bring additional precipitation, mainly to the mountains.

SHORT TERM /Through Monday Night/

Issued 317 AM MDT SAT JUN 6 2026 First of two north Pacific cold fronts was moving eastward across our Idaho zones during the night, marked only by some cloudiness and moderate west wind. The second cold front, due early this morning in eastern Oregon and later this morning in western Idaho, will be stronger, supported by a more energetic short wave trough aloft pivoting inland and through our CWA. Neither front has enough moisture for pcpn in our CWA, but instability under the cold core aloft will develop rain and snow showers along our northern CWA border late Saturday night and Sunday morning. After temporary clearing later Sunday the next North Pacific cold front will move rapidly onto the northwest coast Sunday night. Clouds will increase overnight into Monday morning with showers spreading eastward across our CWA later Monday and Monday night.

LONG TERM /Tuesday through Saturday/

Issued 317 AM MDT SAT JUN 6 2026 Tuesday will finally bring measurable rain to our CWA after more than a month of dry weather, as a well-defined cold front moves eastward across our zones supported by a deep upper low coming inland across WA. The low will move across northern ID Tuesday night and into MT Wednesday. This track will continue cool, showery, and frequently windy weather in our CWA, with snow as low as 4500 feet MSL in the central Idaho mountains Tuesday. Total pcpn through Thursday should be .25 to .75 inch in Idaho north of the Snake Basin and in eastern Baker County/OR, with .05 to .25 inch elsewhere, including the Snake Basin in ID. Least pcpn (around .05 inch) is expected in central and northern Malheur County/OR. Snow may accumulate an inch in eastern Valley County and northern Boise and Elmore Counties above 5000 feet. As the upper low exits Wednesday another weaker low will follow in quickly behind it, maintaining the cool, showery wx into Thursday, at least on the Idaho side. After that low exits Thursday night our CWA will begin a warming and drying trend that will last through at least next weekend.

AVIATION /12Z Saturday through Sunday/

Issued 537 AM MDT SAT JUN 6 2026 VFR with broken clouds AOA 15 kft MSL. Surface winds: NW 5-15 kt, gusts up to 30 kt in the ONO to BKE corridor. After 07/00Z W-NW kt gusts 25 to 35 kt. Winds aloft at 10kft MSL: SW 25-30kt.

KBOI...Increasing clouds above 15kt MSL. Surface wind...NW 15kt, after 06/17Z gusts 25 kt.

Sunday Outlook...VFR. Scattered clouds near 12kft MSL. Gusty W-NW surface wind 15-30 kt in the Snake Basin and south to NV border. Scattered rain/snow showers and local mt obscuration in the Wes-Central Idaho mountains.

BOI WATCHES / WARNINGS / ADVISORIES

ID...Fire Weather Watch from Sunday afternoon through Sunday evening for IDZ424-426. OR...None.