Area Forecast Discussion

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 bring degraded air quality.

- Slightly cooler with near-normal temperatures through midweek.

SHORT TERM /Through Tuesday Night/

Issued 243 PM MDT SUN JUL 26 2026 Southwest flow continues over the area with widespread smoke from area wildfires, with the exception of mostly clear skies along the NV border. Isolated showers and thunderstorms continue this afternoon, mainly over the central ID mountains and along the NV border. Smoky conditions have kept temperatures lower than forecast this afternoon by 5-10 degrees. Have adjusted temperatures Monday and Tuesday slightly lower to account for wildfire smoke using the RRFS and HRRR models. Little improvement expected to wildfire smoke due to lighter winds aloft over the next several days.

LONG TERM /Wednesday through Sunday/

Issued 243 PM MDT SUN JUL 26 2026 Southwest flow aloft will 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 begin to shift over the Great Basin, allowing for temperatures to rise to around 5 degrees above normal. 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 cold front associated with the shortwave will sag south come this weekend, allowing for temperatures to cool to near, or even slightly below, normal by Sunday.

AVIATION /00Z Monday through Tuesday/

Issued 555 PM MDT SUN JUL 26 2026

Wildfire smoke resulting in areas of MVFR/IFR visibility. Slight improvement in visibility during mid afternoons, before degrading again overnight and early Mon/AM. Potential for high density altitude due to PM heat. Surface winds: NW-SW 5-15 kt. Evening gusts around 25 kt in portions of E Oregon. Winds aloft at 10kft MSL: SW 10-20 kt.

KBOI...Visibility degraded to MVFR/IFR due to wildfire smoke. Worst conditions expected early Mon/AM. Potential for high density altitude due to PM heat. Surface winds: NW 6-12 kt before sunset. Then variable 2-6 kt overnight.

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 Monday for ORZ062.