textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warm, dry, and smokey through Wednesday.

- Around a 10 to 15 percent chance of thunderstorms near the Idaho/Nevada border on this afternoon and Wednesday afternoon.

- Cold front approaches area on Thursday afternoon.

- Chance of showers/thunderstorms increases Thursday afternoon through Friday.

SHORT TERM /Through Thursday Night/

Issued 232 AM MDT TUE AUG 11 2026 Warm and dry weather will continue through Thursday, with monsoonal moisture generally keeping to our south and east. However, a stray shower or thunderstorm can't be ruled out (up to 15% chance) on the fringe of the monsoonal moisture in southern Twin Falls county this afternoon and Wednesday afternoon. Come Thursday, the deepening trough just to our west will allow for the moisture to overspread our area (especially southwestern Idaho). A shortwave ejecting around this trough will aid in the development of showers and thunderstorms come Thursday afternoon. Increasing cloud cover as this moisture advects north will act to limit the amount of instability able to build in across the area. Isolated to scattered showers will develop Thursday across southwest Idaho, with the best precipitation chances (40-65%) coming near the ID/NV border and the West Central Mountains. The terrain of those areas will also favor instability building in, allowing for isolated thunderstorms come Thursday afternoon.

LONG TERM /Friday through Tuesday/

Issued 232 AM MDT TUE AUG 11 2026 The active pattern established in the short-term will continue into the long-term period. With southwest flow continuing behind the ejecting short wave, moisture will continue to overspread our area, continuing chances of showers and thunderstorms. High terrain near the Nevada border and over the Central Idaho Mountains will see the highest potential for accumulating precipitation, with a 60-90% chance currently forecast on Friday and a 30-60% chance on Saturday. Ridging building back into the intermountain west will allow for a drying trend beyond Saturday, with isolated afternoon showers/thunderstorms over higher terrain thanks to lingering moisture. Friday into the weekend will feature below normal temperatures to start, before warming to near normal come Sunday as the ridge builds in.

AVIATION /12Z Tuesday through Wednesday/

Issued 420 AM MDT TUE AUG 11 2026

Generally VFR with periods of MVFR conditions in wildfire smoke, primarily over SE Oregon sites. Mtn obscuration in smoke. High density altitude due to heat this afternoon. Surface winds: light and variable this morning. Then W-NW 5-15 kt this afternoon. Winds aloft at 10kft MSL: W-SW 10-20 kt.

KBOI...VFR with periods of foothill obscuration from wildfire smoke. High density altitude this afternoon due to heat. Surface winds: Light and variable this morning, becoming NW 6-12 kt this afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Quality Alert until 1 PM MDT Wednesday for IDZ011-012-014- 015-029-033. OR...Air Quality Alert until 11 AM PDT Wednesday for ORZ061.