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 /12Z Saturday through Sunday/

Issued 536 AM MDT SAT JUN 27 2026 Generally VFR, with MVFR/IFR possible in/around showers and thunderstorms. Scattered/numerous showers and thunderstorms creating localized gusts to 25-35 kt and heavy rain. Lightning coverage will increase through the day. Mtns obscured. Surface winds outside of storms: variable 5-15 kt, then W-NW 5-15 kt with gusts to 20-25 kt after 16Z. Winds aloft at 10kft MSL: W-SW 15-25 kt.

KBOI...Generally VFR, with MVFR/IFR possible in/around showers and thunderstorms. Periods of rain showers continuing through Saturday evening. A 25% chance of thunderstorms occurring through Saturday afternoon. Thunderstorms will be capable of gusts around 30 kt, heavy rain with lowered vis/cigs, and small hail. Surface winds: becoming W-NW 5-15 kt. Gusts to 20-25 kt in the afternoon.

Sunday Outlook...Showers continuing Sunday, especially over central ID. Isolated PM thunderstorms near NV border. Mtn obscuration. Local MVFR/IFR over mountains in rain/snow. Snow level lowering to 6500-7500ft MSL Sunday morning. Gusty W-NW surface winds Sunday afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Flash Flood Watch through this afternoon for IDZ013. OR...None.