textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Breezy and much cooler today, with lingering showers in northeast OR and the central ID mountains.

- Unsettled conditions through Friday, with rain showers over high terrain and slightly below normal temperatures.

- Slight warming and drying trend likely by next Saturday.

SHORT TERM /Through Tuesday Night/

Issued 316 AM MDT SUN SEP 13 2026 The anticipated cold frontal passage has brought isolated thunderstorms and a line of moderate to heavy rain showers near Burns and Baker City, OR tonight. A line of precipitation is currently moving near McCall, ID with another along the Harney- Malheur County border as of 2:30AM MDT. Wind gusts up to 45 mph have been observed near these stronger showers. Scattered rain showers and gusty westerly winds will continue through the early morning. The front and associated low pressure system will move to the northeast this morning, with precipitation mostly tapering off over the region by mid morning. Breezy, cloudy, and much cooler conditions will continue through the day. A few rain showers will linger over high terrain in Baker County and over the West Central Mountains. Cool and dry conditions will continue as a longwave trough remains over the region through at least the middle of next week. Temperatures will generally be 4-8 degrees below normal through Tuesday, with more seasonable conditions expected by the end of the week. &&

LONG TERM /Wednesday through Sunday/

Issued 316 AM MDT SUN SEP 13 2026 A cut off low pressure system will deepen over Oregon on Wednesday, bringing a slight chance (15- 25%) of showers over southeast Oregon and high terrain in southwest Idaho. This low pressure over the region will continue to bring unsettled conditions through early Saturday, with cool temperatures, periods of light rain showers, and even a stray afternoon thunderstorm. The best chance of precipitation will be over higher terrain in southwest Idaho and southeast Oregon. High pressure looks to rebuild late Saturday, with a return to warm, slightly above normal temperatures, and dry conditions. Model solutions diverge by Sunday, with hints at another trough bringing showers and slightly cooler temperatures. Other long range models want to keep the ridge of high pressure over the Western US through the early portion of the week.

AVIATION /12Z Sunday through Monday/

Issued 608 AM MDT SUN SEP 13 2026

Mainly VFR. Lingering clouds and rain showers in central ID tapering off by early afternoon as the cold front moves northeast. Patchy valley fog tomorrow morning near KBKE, KMYL, and KBNO. Surface winds: W to NW 5-15 kt, with gusts to 20-30 kt in the Magic Valley and on ridgetops. Winds aloft at 10kft MSL: SW-W 25-45 kt.

KBOI...VFR with mid level clouds. Surface winds: WNW 10-15 kt with gusts to 25 kt, decreasing to variable less than 10 kt overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.