textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Isolated showers and thunderstorms are expected Tuesday afternoon afternoon and evening.

- Warmer and drier conditions Tuesday through Thursday.

- Trough passage on Friday could bring thunderstorms to central Idaho and breezy winds to the area.

- 4th of July looks dry with temperatures near normal.

SHORT TERM /Through Wednesday Night/

Issued 215 PM MDT MON JUN 29 2026 Light showers will continue across the area through this evening under lingering moisture and weak dynamics on the back side of the departing low pressure system. As the upper level support departs, skies are expected to clear overnight, allowing temperatures to reach about 5 degrees below normal values.

A shortwave passage is on track for Tuesday afternoon and will combine with residual low level moisture and weak instability to support isolated thunderstorm development. High resolution models indicate a few storms will initially develop across Malheur and Baker County Tuesday afternoon before tracking eastward into southwest Idaho during the late afternoon and early evening hours. The main threats with these storms will be gusty outflow winds and lightning.

By Wednesday, the shortwave exits to the east, bringing mostly clear skies back to the region. Daytime heating will lead to cumulus clouds developing over the higher terrain by the afternoon. While most of the forecast area will remain dry, isolated thunderstorms are possible (20% chance) along the Idaho/Nevada border and across the central Idaho mountains where moisture and instability remain sufficient. Temperatures will gradually warm through the short term period, reaching the low 80s in the Western Snake River Basin by Wednesday.

LONG TERM /Thursday through Monday/

Issued 215 PM MDT MON JUN 29 2026 Continued troughing will remain over the region Thursday and Friday, with the last of the embedded shortwaves moving through Thursday into Friday. This final push will bring isolated showers and thunderstorms across the higher terrain of SW Idaho, and cooler than normal conditions through the end of the week. Over the weekend, the Four Corners ridge look to intensify, brining higher geopotential heights and rising maximum daily temperatures. This will bring temperatures back up to near normal. The timeliness of warming (but not too warm) temperatures and dry conditions should make for a pleasant Fourth of July. There is an outside chance (10-20% probability) of temperatures exceeding 95 degrees on July 4th through the lower Snake Plain. Ensembles hint that on Sunday and Monday, the region will develop southwesterly flow aloft between weak troughing moving into the Pacific NW and the persisting Four Corners ridge. This would continue the warm trend, with showers and thunderstorms coming back into the forecast.

AVIATION /06Z Tuesday through Wednesday/

Issued 1126 PM MDT MON JUN 29 2026 VFR. Isolated showers and thunderstorms Tue/PM, mainly over the ID W- Central mtns and near the ID/NV border. Thunderstorms capable of 25 kt outflows. Surface winds: Light and variable overnight, then W-NW 8-12 kt Tue/PM. Winds aloft at 10kft MSL: W-NW 5-20 kt.

KBOI...VFR. Low chance of rain (<15%) Tue/PM. Surface winds: Light and variable overnight/then NW 5-10 kt Tue/PM.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.