textproduct: Boise

KEY MESSAGES

- Warm, dry, and smokey through Wednesday.

- Slight 10 to 15 percent chance of isolated thunderstorms near southern Idaho boarder on Tuesday and Wednesday afternoon.

- Weak Cold Front approaches area on Thursday afternoon.

- Chance of thunderstorms increases Thursday afternoon through Friday.

SHORT TERM /Through Wednesday Night/

Warm and dry weather will continue. However, satellite imagery and some high resolution forecast models suggest a slight (10 to 15 percent) chance of isolated thunderstorms near the southern Idaho border on Tuesday and again Wednesday afternoon. Poor air quality due to wildfire smoke continues to be an issue as well. In addition to smoke produced by local fires, westerly transport winds will continue to bring smoke from numerous large fires in central and southern Oregon across the forecast area. Recent upper air soundings indicate better mixing condition each afternoon, but night time surface based temperature inversions will cap mixing and allow smoke to settle thickly into most valley locations again overnight.

LONG TERM /Thursday through Monday/

A shift in the long term weather pattern will bring slightly cooler and wetter weather for the end of the week. A weak upper level trough will move into the Pacific Northwest late Wednesday, shifting the high pressure that brought hot and dry conditions earlier in the week to the east by Thursday. Monsoonal moisture will advect into the region from the south, with increased chances of showers and thunderstorms beginning early Thursday and peaking on Friday and Saturday. High terrain near the Nevada border and over the Central Idaho Mountains will see the highest potential for accumulating precipitation, with a 40-60% chance currently forecast on Friday and Saturday. Heavy rainfall in these regions will bring a flash flood threat, especially over steep and rocky terrain and recent burn scars. Cooler temperatures will occur from Thursday through Sunday, with highs about 4-6 degrees below normal through the weekend. Moisture will taper off late Sunday into Monday, with a ridge building back in over the Intermountain West, bringing a return to warm and mostly dry conditions for early next week.

AVIATION /18Z Monday through Tuesday/

Issued 1125 AM MDT MON AUG 10 2026

Generally VFR with periods of MVFR conditions in wildfire smoke this evening, primarily near KBNO. Periods of mtn obscuration in smoke. High density altitude due to heat this afternoon. Surface winds: W-NW 10-15 kt with gusts up to 25 kt, then generally variable less than 10 kt overnight. Winds aloft at 10kft MSL: W-SW 10-20 kt.

KBOI...VFR with smoke resulting in some visibility degradation and foothill obscuration. Smoky conditions improving this afternoon. Surface winds: NW 8-12 kt with gusts to around 18 kt this afternoon, then variable less than 10 kt overnight.

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.