textproduct: Boise

KEY MESSAGES

- Isolated to scattered thunderstorms this afternoon and evening across portions of southern Idaho. Storms may produce outflow wind gusts up to 40-60 mph, possibly moving through the Treasure and Magic Valleys.

- Gusty winds late this afternoon and evening, with breezy conditions continuing each afternoon through the week.

- Hot temperatures continue, hottest Friday and Saturday. - Shower and thunderstorm chances return early next week.

SHORT TERM /Through Friday Night/

Moisture will linger over southwest Idaho today under southwesterly flow aloft, bringing another round of isolated to scattered afternoon and evening thunderstorms. Thunderstorms will develop along the higher terrain south of the Snake River in far southern Idaho and lift northeast. Storms are expected to weaken upon reaching the Snake Basin, but a few storms will persist as they enter the Magic Valley and southern Boise Mountains. Lightning and gusty winds 40-60 mph will be the primary hazards from storms, with localized blowing dust possible from outflows. Brief heavy rain is also possible in stronger storms. Thunderstorms should track to the east of the Boise Metro, but outflow gusts to 40 mph from distant storms are possible.

Otherwise today, expect similar temperatures to yesterday with highs in the mid to upper 90s in the lower elevations with 80s to lower 90s in mountain valleys. Late this afternoon and evening, northwest wind gusts 20-35 mph will develop in many areas as an upper trough over British Columbia tracks east and sends a weak, dry cold front through our area. Breezy conditions with gusts 15-30 mph will continue into Thursday, strongest across southern Idaho. Breezy and dry conditions will result in elevated fire weather conditions. Westerly flow aloft will push moisture and the accompanying thunderstorm threat to our east. High temperatures will cool by 3-5 degrees. On Friday, a strong upper level ridge over the Desert Southwest will begin to build north, bringing hotter temperatures. Lower valleys will reach the upper 90s to around 100 degrees. For Boise, there is around a 50-60% chance of reaching triple digits for the first time this season. Southwest flow aloft will bring breezy conditions to the higher terrain.

LONG TERM /Saturday through Wednesday/

The center of a strong upper level ridge will move across the Rocky Mountains and into the Northern Plains this weekend into early next week. Temperatures will remain very hot on Saturday with lower valley highs around 100 degrees. Temperatures should cool a couple degrees for the rest of the period as the ridge axis moves east. However, a slight shift west of the ridge would produce hotter temperatures. Expect locally breezy conditions each afternoon.

Ensembles are in excellent agreement that monsoonal moisture will work its way north around the ridge into our area early next week. This will reintroduce the potential for showers and thunderstorms, especially across the higher terrain. An increase of clouds and precipitation will also likely aid in the slight cooldown. Ensemble mean precipitable water values climb to 150-200% of normal, or above the 90th percentile. Heavy rainfall and flash flooding especially on recent burn scars could be a concern with deep moisture in place. Additionally, after a period of hot, dry conditions, lightning on dry fuels could be a concern for new fire starts, especially if significant rainfall ends up being more limited.

AVIATION /06Z Wednesday through Thursday/

Issued 1204 AM MDT WED JUL 8 2026 Mainly VFR. Isolated showers/thunderstorms in far E Oregon and SW Idaho, dissipating by Wed/08Z. Scattered storms return Wed afternoon mainly across SW Idaho. Storms capable of 30-50 kt outflows, brief heavy rain, and blowing dust. Localized terrain obscuration from wildfire smoke. High density altitude this week due to heat. Surface winds outside of storms: variable 5-15 kt. Winds aloft at 10kft MSL: variable or SW 5-20 kt.

KBOI...VFR. Potential for outflow wind gusts 15-25 kt and light rain before Wed/08Z due to dissipating storms. Then, a 30% chance of shower/thunderstorm outflows (30-50 kt) reaching KBOI after Wed/23Z. Visibility reductions due to nearby wildfire smoke, with foothills obscured. High density altitude this week due to heat. Surface winds: light and variable, transitioning to SE-E 5-12 kt overnight. Winds aloft at 10kft MSL over KBOI: W-S 10-20 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning from 1 PM this afternoon to 8 PM MDT this evening for IDZ423-426. OR...None.