textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Continued hot through Sunday then gradual cooling through next week.

- Smoke persisting through the weekend into next week.

- Breezy afternoon winds through Monday.

- Isolated late-day thunderstorms near the ID/NV border Saturday and Sunday as high-level monsoon moisture advances northward.

SHORT TERM /Through Monday Night/

Issued 203 AM MDT SAT AUG 8 2026 Hot and Smoky conditions will continue to persist through the weekend. This afternoon is looking to be the hottest day of the period...However wildfire smoke will likely help keep temperatures a couple degrees cooler than what they could be. With satellite imagery before sunset and webcams showing a dense smoke plume working it way towards our area, have opted to lower the forecast temperature this afternoon. Even with the smoke, it will still be hot with lower elevation and high desert temperatures reaching 95-103 degrees. A weak upper-level disturbance will work its way though late Saturday into Sunday, and give way to a cooling trend come Sunday and Monday. With temperatures cooling to near normal by Monday. this disturbance will also bring breezy conditions through Monday. The strongest gusts, however, will come each evening with the Baker Valley drainage winds in Oregon; here, evening gusts will be as high as 25-30 mph.

A push of monsoonal moisture will continue to work its way up to the ID/NV border come this afternoon and Sunday afternoon. This moisture, paired with weak instability, will give way to a slight chance of showers and thunderstorms both afternoons near the ID/NV border. Model soundings prog a very dry boundary layer, with surface relative humidity generally ranging from 10-15%. With this, little (if any) precip will reach the ground out of any showers/thunderstorms that develop. However, with deep inverted-v soundings, even virga showers can produce gusty and erratic outflows. The disturbance mentioned prior will push the mid-level moisture south and east, ending the risk of showers/thunder come Monday.

LONG TERM /Tuesday through Saturday/

Issued 203 AM MDT SAT AUG 8 2026 A gradual cooling trend will set in for the long-term period, as the Great Basin high pressure aloft weakens and shifts towards the Four Corners region. Near zonal flow aloft will keep the area dry for the start of the long-term period. Come mid-week this coming week, a deepening trough near the west coast will put our area under more southwesterly flow aloft. This will allow for mid-level moisture to work its way north again. The LREF mean has positive PWAT anomalies reaching the Nevada border come Thursday, continuing to push north through the end of the period. This will allow for increasing chances of showers and thunderstorms to end the coming work week. At the end of the period, timing becomes uncertain on when the aforementioned trough will come across our area.

AVIATION /18Z Saturday through Sunday/

Issued 1107 AM MDT SAT AUG 8 2026 Widespread MVFR-IFR visibility and mountain obscuration due to wildfire smoke. High density altitude due to hot afternoon temperatures. A 15% chance of thunder along the ID/NV border this afternoon. Surface winds: W-NW 10-20 kt this afternoon, with gusts 20-25 kt near KBKE and KONO in the evening. Winds aloft at 10kft MSL: W-SW 10-20 kt.

KBOI...Smoke from nearby wildfires impacting visibility with periods of MVFR conditions. Periods of foothill obscuration. Surface winds: NW 5-10 kt with gusts up to 18 kt this afternoon through evening, shifting SW 5-10 kt late tonight through Sunday morning.

Sunday Outlook...Areas of MVFR/IFR visibility and local mountain obscuration due to wildfire smoke. High density altitude due to hot temperatures. A 15% chance of afternoon thunderstorms along ID/NV border. Surface winds: W-NW 5-15 kt with gusts 15 to 25 kt Sunday/PM, otherwise variable less than 10 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Quality Alert until 1 PM MDT Monday for IDZ011>015-028-029- 033. Heat Advisory until 9 PM MDT this evening for IDZ012-014>016- 029-030-033. OR...Air Quality Alert until 1 PM MDT /noon PDT/ Monday for ORZ061>064. Heat Advisory until 9 PM MDT /8 PM PDT/ this evening for ORZ061>064.