textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Scattered thunderstorms south of a line from Burns OR to Jordan Valley OR to Jerome ID, late this afternoon and evening.

- Thunderstorms capable of producing outflow winds up to 55 mph this afternoon and evening.

- A slight chance thunderstorms again Wednesday afternoon in the central ID mountains and Magic Valley, and again Friday- Saturday in the Central ID Mountains and near the Nevada border.

- A slight warming trend Tuesday and Wednesday, then gradually cooling the rest of the week with breezy conditions.

SHORT TERM /Through Wednesday Night/

Issued 220 PM MDT MON AUG 24 2026 A weak disturbance embedded in southwest flow over the area and monsoonal moisture will trigger scattered showers and thunderstorms over far SE Oregon and southern ID this afternoon and evening, generally from Burns OR, to the Owyhee Mountains to the Magic Valley. Strong gusty outflow winds to 55 MPH may accompany some storms. Storms will generally weaken into showers as they move northeast into the Snake Basin, but gusty outflows and blowing dust will still be a threat. Showers taper off overnight. An upper level ridge axis will remain just east of the area Tuesday and Wednesday while low pressure remains situated off the Pacific Northwest. This will keep southwest flow over the area with temperatures trending up slightly. A weak wave will move over the region on Wednesday resulting in an uptick in winds (mainly across SE Oregon) and a slight chance of thunderstorms across the central ID mountains and from the Magic Valley south to along the Nevada border.

LONG TERM /Thursday through Monday/

Issued 220 PM MDT MON AUG 24 2026 persist Thursday, although a gradual cooling trend will continue through the week. A weak shortwave Friday will begin the breakdown of an upper-level ridge, and lead to a slight chance of precipitation come Friday, mainly across the higher terrain of southwest and central Idaho. Although as of now moisture looks rather limited. Come Sunday, guidance is in good agreement of another low coming down the British Columbia coast and swing past past our area. This low, and associated cold front, will bring a cool down and increased precipitation chances (most pronounced in the central ID mountains). Temperatures on Sunday will likely swing below normal following the cold frontal passage, with the lower Snake Plain having a 40% chance of the afternoon high being below 80 degrees. Breezy conditions will persist throughout the long-term period.

AVIATION /00Z Tuesday through Wednesday/

Issued 551 PM MDT MON AUG 24 2026 Scattered Thunderstorms producing gusty outflows to 45-50 kt through 03Z in southwestern Idaho and southeastern Oregon will remain generally south KBNO-KBOI-KSNT line. Thunderstorms tapering off after 03Z. Surface winds outside of storms: Variable 5-10 kt. Winds aloft at 10kft MSL: SW 5-15 kt.

KBOI...VFR. Isolated showers this evening, with distant CBs south this evening. A 40% chance of outflows to around 30 kt this evening from showers and distant storms. Surface winds outside of outflows: SE 5-10 kt overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning until 8 PM MDT this evening for IDZ423-426. OR...Red Flag Warning until 8 PM PDT this evening for ORZ670>672. Air Quality Alert until noon PDT Wednesday for ORZ062.