textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Showers and isolated thunderstorms for the central Idaho mountains today through Tuesday. - Snow above 6500 feet in central Idaho today.

- Temperatures 15 to 20 degrees below normal through Monday, warming through the week.

SHORT TERM /Through Tuesday Night/

Issued 235 AM MDT SUN JUN 28 2026 A trough of low pressure will dominate through Tuesday with temperatures remaining well below normal. Instability and precipitation will generally be limited to the central Idaho mountains as the low tracks to the north and east through mid week. Isolated thunderstorms will remain a possibility, especially over higher terrain, but will be more limited in coverage than the past couple days. Thunderstorm probability peaking around 10-15% today through Monday, with the afternoon and evening the most favorable time periods. Impressive precipitation totals possible over the central Idaho mountains through Tuesday with an 80-90% chance of greater than 0.5 inches and a 60-80% chance of greater than 0.75 inches. Snow levels are expected to be around 6500 feet today and there is greater than a 90% chance of 3 inches or more of the white stuff at higher elevations through Monday. Saturated soils from the precipitation of the past two days along with what to come will likely cause areas of rockfall and some potential for flooding in portions of the west central Idaho mountains. A Flood Watch is in effect for that area this afternoon through Monday afternoon.

LONG TERM /Wednesday through Sunday/

Issued 235 AM MDT SUN JUN 28 2026 Steady warming is anticipated along with a drying trend mid to late week. There is good agreement that general troughing will be in place through Thursday, then some disagreement on how the next area of low pressure is handled. This next low is expected to be approaching the region Thursday into the weekend and models are diverging on whether the low drops to the west or progresses through. If the low tracks on a more westerly track we could see significant warming to above normal as southwest flow moves in aloft. A more progressive pattern would moderate this warming somewhat. In either case, a return to more seasonably dry conditions seems likely.

AVIATION /12Z Sunday through Monday/

Issued 540 AM MDT SUN JUN 28 2026 Generally VFR. Isolated showers and thunderstorms possible for most sites, with showers likely and isolated thunderstorms for the central Idaho mountains including KMYL. MVFR/IFR possible in/around storms with terrain obscured. Surface winds outside of storms: variable less than 15 kt, becoming WNW 10-20 kt after 17Z Sunday. Winds aloft at 10kft N 10-15 kt.

KBOI...VFR. Isolated showers and thunderstorms possible 18-05Z. Brief MVFR/IFR possible in any storms that develop. Terrain obscured to the north and east of the terminal. Surface winds outside of storms: variable less than 10 kt, becoming WNW 10-15 kt after 16Z. Winds aloft at 10kft N 10-15 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Flood Watch from noon MDT today through Monday afternoon for IDZ011. OR...None.