textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Breezy and cooler today, with showers continuing in the north, but becoming sunny in the south.

- Warmer and drier Tuesday through Thursday.

- Cooling, breezy weather, Friday through Sunday, with showers possible in northern areas Saturday.

SHORT TERM /Through Wednesday Night/

Issued 202 AM MDT MON SEP 7 2026 Cold front, with showers and isolated thunderstorms, passed through western ID Sunday evening and will be out of our CWA before sunrise. Strongest frontal gusts Sunday evening were from the west 35 to 55 mph in the Snake Basin between Mountain Home and Twin Falls. The main shower band was still over our eastern CWA zones at 1 AM MDT. Showers in the Magic Valley will shift east of the area by 3 AM MDT. A few trailing light rain showers were evident on radar in western Valley County/ID and Baker County/OR near the center of a weakening upper low. These showers will continue in northern CWA mountains today as the low moves off into MT. We also have a 20% chance of thunderstorms in Valley County/ID this afternoon. Models bring a second upper low from BC across north-central ID tonight. That low looks too weak for more showers but it will continue cloudiness in our northern zones. Meanwhile, southern zones will become sunny today and mostly clear tonight. All areas will be about 10 degrees cooler than yesterday, except Valley County which was already cool yesterday. Tonight looks cooler also, with lows in the 30s in the mountains to mid 40s in the valleys. The cool and still moist air, and lighter winds, will lead to areas of valley fog overnight and early Tuesday morning. After the second upper low moves out early Tuesday morning, weak upper ridging will come in leading to warmer, drier weather Tuesday and Wednesday. High temps Tuesday will be 5 to 10 degrees warmer than today, and Wednesday another 5 degrees warmer, reaching the 80s in the lower southern valleys.

LONG TERM /Thursday through Monday/

Issued 202 AM MDT MON SEP 7 2026 The warm, dry weather will continue Thursday with high temps well into the 80s in the lower valleys and 75 to 85 degrees in the mountains. Later Thursday a new upper trough will dig southward along the BC coast. The trough will push a dry surface cold front southeastward through our CWA Thursday night. The front will bring gusty winds from the west or northwest, followed by cooler, breezy weather Friday through Sunday, with Sunday likely as cool as today. The supporting upper trough will bring a chance of showers to our northern mountain zones Saturday and Sunday, with snow level near 8000 feet.

AVIATION /12Z Monday through Tuesday/

Issued 524 AM MDT MON SEP 7 2026 Cold front has moved east of the area. Scattered light rain showers in w-central Idaho today, with snow level 8kft MSL. Slight chance thunderstorms 07/18Z to 08/00Z. Scattered clouds elsewhere until 08/00Z then clear. Patchy fog/low stratus in northern mountain valleys until 07/16Z, and again after 08/06Z. Surface winds: SW-NW 5-15 kt this morning, then W-NW in the afternoon. Winds aloft at 10kft MSL: W 20-25 kt.

KBOI...VFR. Scattered clouds near 8 kft MSL until sunset then clear. Surface winds: NW 5-10 kt this afternoon, otherwise variable less than 6 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.