textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warm and dry conditions will persist over the next several days.

- Smoky conditions will limit high temperatures by a few degrees and continue degraded air quality.

- Slightly cooler with near-normal temperatures through midweek.

- Return of warmer than normal temperatures late week.

SHORT TERM /Through Wednesday Night/

Issued 312 AM MDT MON JUL 27 2026 Light to moderate southwest flow from the large high pressure system over the Four Corners region will persist over our area through the week. Temperatures will generally stay near seasonal normals. Generally lighter afternoon wind breezes will be expected over the next few days, with the exception of elevated downvalley winds over the Baker Valley corridor each evening. The dense smoke over valleys have moderated peak temperatures, so slightly cooler than normal temperatures remain possible through midweek. Little improvement expected to wildfire smoke due to lighter winds aloft over the next several days. The aforementioned downvalley winds over Baker Valley will continue to steer dense smoke into the Treasure and Magic Valleys, especially during the nighttime and morning hours.

LONG TERM /Thursday through Monday/

Issued 312 AM MDT MON JUL 27 2026 Southwest flow aloft will continue to be the name of the game in the long-term period. With high pressure aloft over the Four Corners region, and troughing over British Columbia, conditions will remain warm, dry, and breezy. Later in the week, the high pressure aloft will shift over the Great Basin, allowing for temperatures to rise to around 5 degrees above normal Thursday and after. Afternoon breezes will increase come Saturday and Sunday, as a shortwave associated with the aforementioned trough moves inland and tightens the pressure gradient over our area. A dry cold front associated with the shortwave will sag south come this weekend, allowing for temperatures to cool to near, or even slightly below, normal Sunday and Monday. Otherwise, the region is expected to remain considerably drier than normal throughout the long-term period.

AVIATION /12Z Monday through Tuesday/

Issued 531 AM MDT MON JUL 27 2026 Wildfire smoke resulting in areas of MVFR/IFR horizontal visibility, and significantly reduced slantwise visibility. Mtns obscured in smoke. Slight improvement in visibility during late afternoons, before degrading again overnight/early mornings. Surface winds: NW- SW 5-15 kt. Valley gusts around 25 kt in portions of E Oregon in the evening through overnight. Winds aloft at 10kft MSL: SW 10-20 kt.

KBOI...Visibility degraded to MVFR/IFR due to wildfire smoke. Worst conditions expected in the morning and nighttime hours. Surface winds: variable 2-6 kt early morning, transitioning NW 5-12 kt late morning with gusts up to 18 kt in the the afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Quality Alert until 2 PM MDT Tuesday for IDZ011>015-028- 029-033. OR...Air Quality Alert until 11 AM PDT this morning for ORZ062.