textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warm and dry conditions will continue through the weekend.

- Smoke will moderate daytime temperatures and continue degraded air quality through the end of the week.

- A dry cold frontal passage Saturday into Sunday will bring gusty winds and elevated fire weather concerns over the weekend.

SHORT TERM /Through Saturday Night/

Issued 313 AM MDT THU JUL 30 2026 An upper level ridge centered over the Desert Southwest will maintain hot and dry conditions across southeast Oregon and southwest Idaho through late Friday. Peak daytime temperatures are still expected to be moderated due to the persistent smoke across much of the forecast area on Thursday, but should still reach around 5 degrees above normal for many locations Friday and Saturday. Lower valley locations will range from the upper 90s to 103 degrees Friday through Saturday, accompanied by low relative humidity values during the peak heating hours. A stalled upper low over British Columbia will begin to move inland through Saturday and is set to bring a dry cold front across the region, bringing gusty west winds over the area and continuing very dry conditions. This pattern will lead to heightened fire weather concerns on Saturday.

LONG TERM /Sunday through Thursday/

Issued 313 AM MDT THU JUL 30 2026 The dry cold front passing over the area through the weekend will continue dry and windy conditions on Sunday. Elevated fire weather concerns will persist through Sunday. Behind the cold front, Sunday through Monday will be 5-10 degrees cooler than normal. As the front moves out east, Monday will see heightened wind gusts mainly over the Upper Treasure Valley and Magic Valley areas, while very dry conditions persist. Temperatures begin to climb again Tuesday and Wednesday as a Pacific high pressure system builds into the Great Basin. Wednesday through Thursday, there is potential for another dry shortwave trough digging across our area from the Pacific coast, but considerable guidance uncertainty remains. Hot and dry conditions will continue through Thursday.

AVIATION /12Z Thursday through Friday/

Issued 552 AM MDT THU JUL 30 2026 Widespread wildfire smoke reducing visibilities with areas of MVFR and IFR conditions. Mountains obscured in smoke. Slight improvements possible in the afternoon. Surface winds: mostly variable 5-15 kt this morning, becoming SW-NW 5-12 kt in the afternoon. Gusty valley winds 10-15 kt with gusts 20-25 kt over KBKE and KONO in the evening. Winds aloft at 10kft MSL: SW 5-15kt.

KBOI...MVFR visibility in smoke from wildfires. Slight improvements possible in the afternoon. Surface winds: SE or variable 4-7 kt, then NW 7-12 kt in the afternoon.

Weekend Outlook...Dense smoke coverage will continue MVFR-IFR conditions and mountain obscurations over the weekend. Dry frontal passage on Saturday will bring gusty NW winds over all areas Saturday afternoon/evening and mainly east of KBOI Sunday afternoon. Surface winds: SW-NW 10-20 kt with gusts 20-30 kt Saturday/Sunday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Quality Alert until 2 PM MDT Friday for IDZ011>015-028-029- 033. Air Quality Alert until 1 PM MDT this afternoon for IDZ016-030. OR...Air Quality Alert until 1 PM MDT /noon PDT/ Friday for ORZ062>064.