textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Continued very warm, dry days through Friday.

- Much cooler, with showers, Saturday through Tuesday.

- Significant rainfall possible in Idaho next week, but confidence is low.

SHORT TERM /Through Friday Night/

Issued 319 AM MDT WED OCT 7 2026 An upper level ridge will keep temperatures very warm through Friday. Highs will be near records each day, with lower valleys reaching the low to mid 80s. Mostly clear skies and light winds through Thursday will allow good radiational cooling at night with low temps in the 40s to lower 50s, except 30s in colder mountain valleys. On Friday, winds will increase as an upper level trough approaches from the northwest. Winds will be strongest across the higher terrain, southeast Oregon, and far southwest Idaho with gusts 25-35 mph. Lower elevations will be more sheltered with gusts 15-25 mph. The upper trough will push a cold front across the area Friday night, ushering in a much cooler air mass for the extended period.

LONG TERM /Saturday through Wednesday/

Issued 319 AM MDT WED OCT 7 2026 High temperatures on Saturday will be 15 to 25 degrees cooler than Friday behind the cold front. Winds will be breezy over the weekend, expanding to lower elevations as the front stalls south of the area. The upper level trough will dive south through Washington and Oregon over the weekend, potentially developing into a closed low and bringing a chance of light rain and high mountain snow to the area. The highest chances (30-60%) will be across Idaho where the low will tap into higher moisture. Even cooler air will arrive on Sunday as the low moves south, dropping highs to 5 to 10 degrees below normal. Snow levels will vary across the area, lowest across southeast Oregon closer to the low center at 4500 to 6000 feet MSL, and 5500 to 7500 feet across southwest Idaho.

The low is expected to continue south into California late Sunday into early next week and interact with tropical moisture from the remnants of Hurricane Rachel. The bulk of the moisture is expected to pass to the east of our area late Sunday, but may clip southern Idaho with potential for significant rain amounts. The low will become cut off from the parent trough moving east across Canada, resulting in ensemble differences on the track of the low as it slowly moves east. A further south trajectory would keep deeper moisture out of our area, but further north could result in significant precipitation amounts early next week. Temperatures will remain below normal, but gradually moderate to near normal by Wednesday. Additionally, with cool air in place, frost will be possible in lower valleys especially if a drier pattern develops. Winds will subside early next week.

AVIATION /12Z Wednesday through Thursday/

Issued 549 AM MDT WED OCT 7 2026 VFR. Clear skies. Areas of smoke and haze may reduce visibility near prescribed burns. Surface winds: variable less than 12 kt. Winds aloft at 10kft MSL: W-NW 5-15 kt.

KBOI...VFR with clear skies. Surface winds: SE 4-8 kt this morning, becoming NW 4-8 kt this afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.