textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Isolated to scattered showers and thunderstorms through this evening, mainly across the higher terrain of eastern Oregon and southwest Idaho south of the Snake Basin.

- Isolated to scattered thunderstorms Wednesday across the higher terrain of central and southern Idaho.

- Storms may produce strong gusty outflow winds, possibly moving through the Treasure and Magic Valleys today and Wednesday. - Hot temperatures through the week and into the weekend. - Breezy winds each afternoon, especially Wednesday and Thursday.

SHORT TERM /Through Thursday Night/

Issued 245 PM MDT TUE JUL 7 2026 Southwest flow aloft will continue to bring monsoon moisture to the area today. Scattered showers and thunderstorms expected along the NV border this afternoon and south of the Snake Basin in Idaho. Isolated thunderstorms possible near Baker County this afternoon and evening too. Dry low levels support shower and thunderstorm outflow wind gusts up to 40-60 mph. Storms will lift northeast off the higher terrain south of the Snake River and weaken as they enter the Snake River Valley. However, gusty outflow winds are possible as storms dissipate in both the Treasure and Magic valleys late this afternoon and evening, with around a 10-20% chance of storms holding together into the valleys.

An upper level trough moving into British Columbia on Wednesday will begin to push moisture to the east. This will limit the chance for afternoon and evening showers and thunderstorms to the higher terrain of southern and central Idaho, although thunderstorms and outflow gusts may also drift north into the Magic Valley. A weak, dry cold front will move through Wednesday night and Thursday pushing the lingering moisture and thunderstorm threat to the east. Temperatures will remain steady on Wednesday, then cool a few degrees Thursday behind the front. The front will bring gusty winds to the area Wednesday night, continuing into Thursday across southern Idaho with gusts 20-35 mph. Low humidity with gusty winds will increase fire weather concerns.

LONG TERM /Friday through Tuesday/

Issued 245 PM MDT TUE JUL 7 2026 High pressure aloft will begin to develop over the Great Basin come Friday, before expanding east over the Rocky Mountains and the High Plains. A trough over southeast Alaska will help keep our area under southwest flow aloft and the hottest temperatures to the east. However, lower elevation temperatures will still rise to the upper 90s/near triple digits throughout the long- term period. These temperatures will result in widespread moderate with localized major HeatRisk for this weekend into early next week. Each afternoon will feature breezy winds across higher terrain, with gusts to 20-30 mph.

Come Monday, monsoonal moisture will begin to work around the ridge and across our area. The Grand Ensemble continues to show a strong signal for this moisture, with precipitable water values increasing to near the 95th percentile of climatology by Monday afternoon. With moisture values that high, the flash flood risk will have to be monitored (especially across recently burned areas), as the threat of showers and thunderstorms increases come Monday/Tuesday.

AVIATION /00Z Wednesday through Thursday/

Issued 558 PM MDT TUE JUL 7 2026

Mainly VFR. High density altitude this week due to heat. Isolated showers/thunderstorms near NV border in OR/ID. Storms capable of 30-50 kt outflows, brief heavy rain, and potential for blowing dust. Localized terrain obscuration from wildfire smoke. Surface winds outside of storms: variable 10 kt or less. Occasional gusts around 15 kt through sunset. Winds aloft at 10kft MSL: variable or SW 5-20 kt.

KBOI...VFR. A 30% chance of storm outflow gusts to 20-30 kt this evening from dissipating storms. Measurable rain unlikely. Visibility reductions due to nearby wildfire smoke, with foothills obscured. High density altitude this week due to heat. Surface winds: NW 5-15 kt through this evening, transitioning to SE-E 5-12 kt after sunset. Winds aloft at 10kft MSL: W to WNW 15-20 kt this evening.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning until 9 PM MDT this evening for IDZ423-426. Red Flag Warning from 1 PM to 8 PM MDT Wednesday for IDZ423- 426. OR...Red Flag Warning until 8 PM PDT this evening for ORZ672.