textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warmer today, especially in southern Idaho. - Widespread showers tonight through Tuesday morning, with a slight chance of thunderstorms Tuesday. - Warming and drying Thursday through Saturday.

SHORT TERM /Through Wednesday Night/

Issued 315 AM MDT MON JUN 8 2026 Warmer today, especially in Idaho, as a flat upper ridge passes overhead, before a north Pacific trough comes in tonight and Tuesday. Southern Idaho will be up to 15 degrees warmer than yesterday, while the central Idaho mountains warm about 10 degrees, and eastern Oregon only about 5 degrees due to clouds increasing sooner there. Showers should begin in Harney County around 2 PM PDT this afternoon, then spread eastward to the Idaho border by 6 PM MDT, and to Twin Falls before midnight. The trough looks moist and energetic now while it is still offshore but latest models weaken it when it gets to our CWA tonight. Even so, all parts of our CWA should get at least some rain tonight and Tuesday morning. There is also a 15 percent chance of thunderstorms in northern areas Tuesday. But eastern OR will already begin clearing by noon Tuesday and even western ID should start clearing Tuesday afternoon, except in the central ID mountains where showers will continue through Wednesday morning. Total forecast pcpn has also decreased, now only .25 to .50 inch in the Idaho mountains tonight through Wednesday, and less than .20 inch elsewhere. The upper trough is also forecast shallower than before, and with less cold air the snow level will not dip as low as previously forecast. Light snow will still fall in the central ID mountains, but less than one inch is forecast below 6000 feet. Tuesday will still be quite cool with high temps in the 50s and lower 60s in the mountains, and mid 60s to mid 70s in the valleys. Pre-frontal southeast through southwest wind gusts will increase to 25 to 35 mph this afternoon in open areas, and post-frontal west winds will become at least that strong Tuesday, especially on the Idaho side where gusts should reach 40 mph Tuesday afternoon, decreasing Tuesday night.

LONG TERM /Thursday through Monday/

Issued 315 AM MDT MON JUN 8 2026 The secondary upper trough that models forecast in our CWA Wednesday has now been shifted north of our CWA so only our northern mountains should still have showers Wednesday. Northwesterly flow aloft will keep our CWA cool Wednesday, but Thursday will be noticeably warmer with highs reaching 80 degrees in the southern valleys and 60s through 70s elsewhere. Clear skies and further warming are expected Friday through Sunday but the warming will be limited by northerly wind component aloft.

AVIATION /12Z Monday through Tuesday/

Issued 542 AM MDT MON JUN 8 2026 Showers beginning in eastern Oregon mid-afternoon today, spreading eastward with a cold front into ID this evening. Mountains becoming obscured with local MVFR in clouds/pcpn in northern mountains Monday night. A 10-15% chance of thunderstorms Tuesday north of the Snake Basin. Snow level briefly lowering to 5500-6000 feet MSL Tuesday morning, then rising to 7000-8000 feet MSL Wednesday.

Surface winds: variable less than 10 kt, becoming S-SE 7-12 kt with gusts 20-25 kt after 08/18Z Monday. Winds aloft at 10kft: SW 15-20 kt until 18Z Monday, increasing to 20-25 kt after 18Z.

KBOI...VFR with increasing high clouds. Rain after 09/02Z, Surface winds: SE less than 10 kt, becoming SE 7-12 with gusts to 20 kt after 15Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.