textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Scattered thunderstorms this afternoon and evening could produce strong outflow winds, small hail and brief heavy rain.

- Temperatures around 15 to 20 degrees below normal this weekend.

- Significant precipitation and light snow above 7000 feet possible this weekend.

SHORT TERM /Through Monday Night/

Issued 258 AM MDT SAT JUN 27 2026 An unseasonably cool trough of low pressure will drive the weather into early next week. Cooling aloft associated with the low will generate nearly continuous atmospheric instability. Showers and thunderstorms are expected throughout the weekend, with a noticeable increase in activity during the afternoon and evening hours. Thunderstorm probability ranges from 20% to 40% today, and around 20% on Sunday. Shower activity is expected to be area-wide today, and focused over the Idaho mountains on Sunday. Stronger storms that develop will have the potential for heavy rainfall, frequent lightning, small hail and gusty winds. Temperatures are expected to be 15 to 20 degrees below normal.

LONG TERM /Tuesday through Saturday/

Issued 258 AM MDT SAT JUN 27 2026 Very good agreement that long wave troughing will remain in place through the weekend. As the trough axis migrates just to the east of the area, a drop in available moisture will occur, reducing the potential for precipitation mid week. By late in the week there are hints that a secondary low will drop into the broad trough and bring a better chance of precipitation for the holiday weekend. Temperatures are expected to slowly warm through the week, approaching normal by the end of the week.

AVIATION /18Z Saturday through Sunday/

Issued 1239 PM MDT SAT JUN 27 2026

Generally VFR. Scattered/numerous showers and scattered thunderstorms this afternoon. MVFR/IFR conditions possible in thunder and showers. Thunderstorms capable of heavy rain, small hail, and gusts to 30 kt. Thunder tapering off after Sun/00z, with showers lingering overnight, mainly over the W-Central ID Mtns. Surface winds: W-NW 5-15 kt with gusts to 20-25 kt in the afternoon. Then W-NW 5-15 kt overnight, except W-SW 10-15 kt with gusts to around 25 kt near KTWF/KJER. Winds aloft at 10kft MSL: W-NW 15-25 kt.

KBOI...Generally VFR, with brief MVFR/IFR conditions possible in showers/thunder. Scattered showers and thunderstorms continuing this afternoon, a 25-30% chance of thunder impacting terminal through Sun/00z. Thunder capable of heavy rain, small hail, and 30 kt outflows. Showers tapering off after Sun/00z. Ceilings lowering to MVFR early Sun/AM. Surface winds: W-NW 10-15 kt with gusts to 20-25 kt this afternoon. Then NW 8-13 kt overnight.

Sunday Outlook...VFR/MVFR in low ceilings and precip, with localized IFR in mtn rain/snow. continuing Sunday, especially over central ID. Isolated PM thunderstorms near NV border and W-Central ID Mtns. Mtn obscuration. Snow levels lowering to 6500-7500ft MSL Sunday morning. Gusty W-NW surface winds Sunday afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Flash Flood Watch until 9 PM MDT this evening for IDZ013. OR...None.