textproduct: Boise

UPDATE

Updated aviation discussion.

SHORT TERM /Through Thursday Night/

Issued 313 AM MDT TUE JUN 9 2026 Cold front currently weakening as it moves eastward across ID. At 3 AM MDT the front extended through Salmon - Twin Falls with a narrowing band of showers along it. However, radar showed another band of showers in western Idaho parallel to the frontal band, also moving eastward, so the showers aren't finished in ID yet. Showers are finished in eastern OR, though. Later this morning, post-frontal instability under colder air aloft will develop a 15 to 25 percent chance of thunderstorms north of the Snake Basin in ID, and also in southern Twin Falls County. These should last until sunset. Showers in ID will also end late today except in the west central Idaho mountains and Boise Mountains where a following short wave trough will pass through tonight and Wednesday morning. Models have varied on the second trough the last couple days. Yesterday's models kept it north of our CWA, but today they agree it will clip our CWA after all. So we have a 20-40 percent of rain showers in Valley County on Wednesday. Post-frontal west/northwest winds will increase to 20-30 mph today, with gusts up to 45 mph this afternoon in the central Snake Basin and Camas Prairie, but blowing dust should not be a problem due to tonight's rain. Today's upper trough and the second one tonight/Wednesday will keep temps cool, with high temps only in the upper 50s and 60s in the mountains, and mid 60s to mid 70s in the lower valleys. Lows tonight and Wednesday night will be in the 30s in the mountains and 40s in the valleys. Wednesday night should be even cooler as skies clear, winds die down, and we are still under northerly flow aloft. Lows Wednesday night will dip to the upper 20s to mid 30s in the ID mountains, and mid 30s to lower 40s in the valleys. High temps Thursday will be a full 10 to 15 degrees warmer than highs Wednesday as the upper troughs move away and a ridge of high pressure builds inland from the Pacific.

LONG TERM /Friday through Tuesday/

Issued 313 AM MDT TUE JUN 9 2026 Warming and drying will continue through Monday as the Pacific upper ridge edges slowly inland, but the warming will be slowed by increasing northerly flow aloft over Idaho due to a trough in Montana and the northern Plains. Skies will stay clear in OR but partly cloudy in Idaho due to the trough.

AVIATION /12Z Tuesday through Wednesday/

Issued 608 AM MDT TUE JUN 9 2026 Surface cold front in eastern ID, with early morning showers decreasing in western ID. Areas of MVFR ceilings and mountain obscuration in ID until 15Z, otherwise VFR. Patchy fog and brief IFR in valleys until 15Z. Isolated thunderstorms developing north of the Snake Basin in ID after 16Z, continuing until 10/03Z. Surface winds...SW-NW 15-25kt. Afternoon gusts 30 kt in the Snake Basin. Gusts to 35 kt in thunderstorms. Winds aloft at 10kft MSL...W 20-25kt.

KBOI...VFR. Broken-overcast near 12 kft becoming scattered clouds by 16Z. Surface winds...variable less than 10kt until 15Z then NW 12-15kt. Gusts to 25 kt from 21Z to 10/00Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.