textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Isolated showers and thunderstorms are expected area-wide Wednesday afternoon and evening, and again on Thursday near the Idaho-Nevada border.

- Dry this weekend into early next week. - Steady warming trend throughout the week with dry conditions and temperatures near normal on the 4th of July.

SHORT TERM /Through Friday Night/

Issued 405 AM MDT WED JUL 1 2026 Morning satellite loop shows several features of interest over the region, including several mesoscale mid-level circulations across eastern Oregon and Idaho embedded within broader cyclonic flow aloft. One of these is contributing to a narrow and focused area of precipitation this morning over the Treasure Valley, which was surprisingly depicted by some convection-allowing models. Mesoanalysis suggests there is marginal instability in place, so can't rule out a few strikes from this activity as it develops northeastward towards the Boise Mountains, before eventually diminishing by late morning.

Isolated showers and thunderstorms will redevelop later this afternoon across southern Idaho and the central Idaho Mountains, with the western Magic Valley (including Twin Falls/Jerome) the most likely area to be affected. The primary threat would be brief and locally gusty winds to 50 mph with the strongest storms.

By Thursday, the threat for thunderstorms becomes more confined to immediately near the Idaho-Nevada border. Temperatures will also continue to warm a few degrees each day, reaching the mid-80s on Thursday, and upper-80s by Friday over the lower elevations - which is right at normal for this time of year. Further drying will also occur into Friday, with the probability of precipitation very low area-wide.

LONG TERM /Saturday through Wednesday/

Issued 405 AM MDT WED JUL 1 2026 The primary hazard leading into early next week will be the increasing temperatures and associated impacts. The general model consensus is for an upper ridge to build and expand to the south and west, which will promote a return of above-normal temperatures. Monday is currently forecast to be the warmest day of the period, with mid-upper 80s common through the Snake Plain, with some locations potentially even getting to 100 degrees. This will bring moderate HeatRisk impacts to populated areas such as Boise and Mountain Home - affecting those that are sensitive to heat. Low-end precipitation chances return by Tuesday, but there currently isn't much signal for showers or thunderstorms outside of the central Idaho Mountains through mid-week.

AVIATION /12Z Wednesday through Thursday/

Issued 538 AM MDT WED JUL 1 2026 VFR. Isolated showers/thunderstorms this morning over central ID mountains. Isolated showers and thunderstorms develop this afternoon, mainly over the ID W-Central mtns and near the ID/NV border, with a 30% chance of affecting KTWF/KJER. Gusty outflow winds of 30-35 kt. Surface winds: W-NW 5-15 kt. Becoming light and variable Thu morning. Winds aloft at 10kft MSL: W-SW 5-15 kt.

KBOI...VFR. Isolated showers/thunderstorms through 01/15Z. Thunderstorms redeveloping to the south this afternoon with distant CBs. Surface winds: NW 7-12 kt. Becoming light and variable by early Thursday morning.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.