textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Weak Pacific cold front will bring isolated thunderstorms to the area Saturday afternoon and evening.

- Gusty outflow winds up to 50 mph possible from thunderstorms.

- Dry and slightly cooler conditions Sunday.

SHORT TERM /Through Monday Night/

Issued 415 AM MDT SAT AUG 22 2026 A cold front will slowly move across central OR today into southwest ID this evening. Showers and thunderstorms expected ahead of the cold front, mainly across southwest ID and far eastern OR. The best dynamics for thunderstorms today will be generally be east of a line from Baker City OR to Jordan Valley OR, with enough effective bulk shear for organized thunderstorm development. Shower and thunderstorm threat continues into the late evening into early Sunday morning before drier air moves in by late Sunday morning. Slightly cooler temperatures expected on Sunday with dry conditions. Isolated thunderstorms possible along the NV border south of Twin Falls Sunday afternoon. A weak shortwave embedded in the southwest flow aloft will bring increased clouds on Monday with slightly cooler temperatures. Isolated showers and thunderstorms will generally be confined to the higher terrain of southwest ID Monday afternoon. Gusty outflow winds up to 50 mph possible with thunderstorms each day.

LONG TERM /Tuesday through Saturday/

Issued 415 AM MDT SAT AUG 22 2026 A trough off the Pac NW coast pushes the monsoon moisture east on Tuesday with drier air, breezy conditions and slightly cooler temperatures Tuesday through Friday. Temperatures will around 2-5 degrees above normal through the period.

AVIATION /18Z Saturday through Sunday/

Issued 1227 PM MDT SAT AUG 22 2026

VFR. Scattered showers and Isolated thunderstorms early this afternoon. Increasing in coverage into this evening with isolated to scattered thunderstorms, mainly in SW-Idaho. Thunder capable of brief heavy rain, hail, and erratic outflows to 40-50 kt. BLDU possible with outflows. High density altitude this afternoon due to heat. Surface winds outside of storms: Variable 5-15 kt, except SW 10-20 kt with gusts to 25-30 kt in E-Oregon. Winds aloft at 10kft MSL: S-SW 10-25 kt.

KBOI...VFR. A 20% chance of thunderstorms this afternoon and evening. Thunderstorms capable of brief heavy rain, hail, and outflows to 40-50 kt. BLDU possible in outflows. High density altitude this afternoon due to heat. Surface winds: W-NW 6-12 kt this afternoon, becoming SE 5-15 kt after Sun/00z.

Sunday Outlook...Generally VFR. Areas of wildfire smoke. Shower and thunderstorm activity in southwest/central Idaho diminishing early Sunday AM. Isolated storms returning near KTWF in the afternoon. Surface winds: SW-NW 5-15 kt with afternoon gusts 15-25 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning until midnight MDT tonight for IDZ401>403-421- 424-426. OR... Red Flag Warning until 8 PM PDT this evening for ORZ670>672.