textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Thunderstorms across portions of southern Idaho may produce outflow wind gusts up to 40-60 mph through this evening.

- Hot with breezy afternoon winds through the weekend. - Shower and thunderstorm chances return early next week.

SHORT TERM /Through Friday Night/

Issued 126 PM MDT WED JUL 8 2026 Thunderstorms got off to an early start today with the first strike hitting before 10AM this morning. Activity will continue into the early evening bringing the potential for local wind gusts up to 60 mph. The strongest outflow winds will be focused east of Hwy 51 and Mountain Home and south of Hwy 20 out to Fairfield. It's not unreasonable that a westward propagating outflow extends further into the Treasure Valley this evening though it is going to be a race between thunderstorm outflows and an evening wind push from the northwest. For now, expect the northwest winds to win the race for most of the Treasure Valley. These winds will first push through SE Oregon counties early this evening, bringing gusts 30 to 40 mph in the typically winder locations. A quieter hot and dry pattern settles in after this evening. High temperatures on Thursday are a few degrees cooler than today with northwest winds ramping up in the afternoon. The heat builds on Friday as an upper high over the Desert SW expands northward. This will put lower elevations near 100 and mountain valleys near 90. Winds will be lighter at lower elevations as southwest flow aloft brings breezy winds to higher terrain.

LONG TERM /Saturday through Wednesday/

Issued 126 PM MDT WED JUL 8 2026 Hot temperatures will persist throughout the long-term period, with the well-advertised ridge shifting east over the Rockies/High Plains. this will bring lower elevation temperatures in the upper-90s and around triple digits. Saturday appears to be the hottest day of the period, with temperatures throughout lower elevations near 100 degrees and localized areas near 105 degrees for daytime highs. Overnight lows will generally stay 5-10 degrees above normal as well.

Come Monday, the signal for a monsoonal push remains, with ensemble guidance continuing to carry precipitable water values around the 95th percentile of climatology. This moisture will help reintroduce thunderstorms into the forecast come Monday and beyond, especially over higher terrain. With that moisture, flash flooding could be a concern, especially over recent burn scars. Another aspect will be the lightning over dry fuels after a long stretch of hot and dry conditions. The antecedent dry conditions combined with lightning potential increases the concern of new fire starts, especially if initial storms take on a dry posture. Both of these hazards will need to be monitored in the days to come.

AVIATION /00Z Thursday through Friday/

Issued 530 PM MDT WED JUL 8 2026

Mainly VFR. Scattered showers and thunderstorms this evening in far SW and S-central Idaho, including KJER/KTWF. Storms capable of outflows to 30-50 kt, small hail, brief heavy rain, and blowing dust. Localized terrain obstruction from wildfire smoke. High density altitude this week due to heat. Surface winds outside of storms:W-NW 5-15 kt, with gusts to 25 kt this evening, except 25-35 kt from KBKE-KONO. Winds aloft at 10kft MSL: S-W 5-15 kt.

KBOI...VFR. High density altitude this week due to heat. Foothills obscured in smoke at times from nearby fires. Surface winds: W-NW 8-13 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning until 8 PM MDT this evening for IDZ423-424- 426. OR...None.