textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Showers and isolated thunderstorms are expected this afternoon and evening across southwest Idaho.

- Precipitation will persist across the West Central mountains through Monday, with another round of showers returning Tuesday afternoon.

- Warmer and drier conditions Tuesday through Thursday.

SHORT TERM /Through Tuesday Night/

Issued 214 PM MDT SUN JUN 28 2026 Scattered showers and isolated thunderstorms will continue this afternoon and evening, with the main focus across southwest Idaho as moisture moves in from the north on the back side of the upper level low. The greatest chance for thunderstorm activity will be over the higher terrain south of the Snake River Plain during peak afternoon and evening heating before tapering off tonight. There is a 30% chance for these light rain showers to reach the Treasure and Magic Valleys tonight through Monday morning, though rainfall looks to be minimal. Showers will continue across the West Central mountains through Monday, finally coming to an end Monday night as the parent low moves east into the northern plains. The central mountains will see additional precipitation totals between 0.25 and 0.75 inches through Monday. Areas above 7500 feet could see an additional 1 to 3 inches of snowfall tonight.

A broad upper level trough remains over the area on Tuesday. This persistent large-scale pattern will allow a weak shortwave passage to cross the region, triggering another round of showers across the west central mountains. Temperatures will remain well below normal, tracking roughly 10 to 15 degrees below seasonal averages through the short term period under the influence of the trough.

LONG TERM /Wednesday through Sunday/

Issued 214 PM MDT SUN JUN 28 2026 Troughing over the region will support isolated showers and thunderstorms across the higher terrain of SW Idaho, and cooler than normal conditions through the end of the week. Most guidance shows this trough deepening just to our west throughout the week. With flow taking on more of a southwesterly component, temperatures will steadily warm. As of now it appears that this warming trend will be more gradual in eastern Oregon. Come Friday, the trough finally looks to progress east of our area. This will temporarily hinder the warming trend on Friday, before a building ridge behind the trough brings temperatures back up to near normal. The timely exit of this trough will make way for a pleasant Fourth of July, with near normal temperatures and dry conditions. The pattern evolution becomes more uncertain to end the period, although the Grand Ensemble favors continued ridging and therefore continued warm and dry conditions.

AVIATION /06Z Monday through Tuesday/

Issued 1128 PM MDT SUN JUN 28 2026 Generally VFR. Light precip mainly across northeast OR and central ID through morning, then isolated/scattered showers across the area Monday afternoon. MVFR/IFR in mtn showers, with light snow above 8kft MSL. Mtns obscured. Surface winds: SW-NW 5-15 kt. Gusts to 15- 25 kt Monday afternoon. Winds aloft at 10kft MSL: NW 15-30 kt.

KBOI...VFR. Periods of light rain before Mon/09Z, then a 15% chance of light rain returning Monday afternoon. Foothills obscured with SCT-BKN clouds between 5000-7000 ft AGL. Surface winds: light and variable overnight, transitioning to NW 5-12 kt mid/late morning. Afternoon gusts around 20 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.