textproduct: Boise

KEY MESSAGES

- Scattered showers and thunderstorms this evening across far eastern Oregon and far western Idaho, with gusty winds, lightning, brief heavy rain, and small hail possible.

- Very hot, dry, and breezy to end the week.

- Areas of smoke will continue through the week.

SHORT TERM /Through Saturday Night/

Convective initiation is already underway in eastern Oregon as of writing this. Isolated to Scattered thunderstorms are anticipated to continue this afternoon into the evening primarily across eastern far eastern Oregon and western Idaho, tracking northeast after initiation. A low off the Oregon coast is helping bring in some monsoonal moisture kicking off these thunderstorms. The strongest storms this afternoon will be capable of heavy rain, small hail, and gusts to 40-60 mph. Some thunderstorms may be able to make it across the Treasure Valley. Southwesterly flow aloft will aid in boosting afternoon temperature today to around 100 degrees, leading to a heat advisory this afternoon.

A warming and drying trend will set in come Friday, with temperatures climbing over 100 degrees throughout much of the lower Snake Plain. The heat advisory will continue through Saturday. Winds will also begin to increase as the aforementioned low creeps closer to shore. Hot, dry, and windy conditions will persist through Saturday across eastern Oregon and higher terrain of southwest Idaho, leading to critical fire weather conditions Friday and Saturday. Most of the area will remain dry after today, aside from the western Magic Valley where lingering moisture will allow for isolated afternoon showers and thunderstorms to develop. Wildfire smoke will linger over the area, most notable each night and morning before mixing out during the afternoons.

LONG TERM /Sunday through Thursday/

After slight cooling Sunday and Monday as an upper trough brushes OR and WA, the rest of the week will trend hotter again. The main upper high, initially centered over the southern Rockies, will shift slowly westward to the southern Great Basin by next weekend. The high is also forecast to intensify as the northern trough moves back off the northwest coast and the next hurricane moves WNW away from the Mexican coast. The resulting pattern will still allow monsoon moisture to reach south-central Idaho for a slight chance of afternoon thunderstorms through the week, but Oregon looks very dry. With most of the wildfires currently located in Oregon those areas will likely remain just smoky and hot.

AVIATION /18Z Thursday through Friday/

Issued 1134 AM MDT THU JUL 23 2026 Generally VFR. Areas of MVFR visibility due to wildfire smoke, improving during peak afternoon heating. Scattered showers and thunderstorms late afternoon/evening in eastern Oregon and far western Idaho, impacting KEUL/KONO/KBKE/KMYL. Outflow gusts 30-50 kt, brief heavy rain, and small hail in strongest storms. High density altitude due to heat this afternoon. Surface winds: variable less than 10 kt this morning, becoming SW-NW 5-15 kt this afternoon. Winds aloft at 10kft MSL: SW 10-20 kt.

KBOI...VFR. High density altitude due to heat this afternoon. Outflow gusts to 25 kt from thunderstorms passing west of KBOI late afternoon and early evening. Surface winds: variable less than 10 kt until 21Z, then NW 5-10 kt 23/21Z through 24/02Z, then variable less than 10 kt.

Weekend Outlook...Areas of wildfire smoke continuing with areas of MVFR visibility during late night and morning hours, improving each afternoon. High density altitude due to heat. Isolated showers and thunderstorms across the Magic Valley each afternoon. Mostly clear elsewhere. Surface winds: SW-NW 5-15 kt with gusts to 25 kt, except 10-20 kt with gusts to 30 kt on Saturday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Quality Alert until 2 PM MDT Friday for IDZ011-012-014-033. Red Flag Warning until 9 PM MDT this evening for IDZ400-420- 423. Red Flag Warning from 2 PM Friday to 9 PM MDT Saturday for IDZ401-402-423. Heat Advisory until 9 PM MDT Saturday for IDZ012-014-016-033. OR...Air Quality Alert until 2 PM MDT /1 PM PDT/ Friday for ORZ061>064. Red Flag Warning until 9 PM MDT /8 PM PDT/ this evening for ORZ672>675. Red Flag Warning from 2 PM MDT /1 PM PDT/ Friday to 9 PM MDT /8 PM PDT/ Saturday for ORZ670>675. Heat Advisory until 9 PM MDT /8 PM PDT/ Saturday for ORZ063- 064.