textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

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

- Isolated thunderstorms confined to the central Idaho mountains and near the Idaho-Nevada border Thursday and Friday, before drying out this weekend.

- Steady warming trend throughout the week with dry conditions and temperatures near normal on the 4th of July.

SHORT TERM /Through Thursday Night/

Issued 219 AM MDT TUE JUN 30 2026 Early morning satellite imagery depicts broad troughing in place across the Northwest, with scattered areas of mid-level cloud cover present. Temperatures are generally running 2-5 degrees above readings yesterday morning, with this difference likely to continue into the daytime as a warming trend commences through the week. Moisture values are above-normal as well, as evidenced by surface dewpoints in the 40s and 50s throughout the Snake Plain. This moisture will favor the development of isolated showers and thunderstorms this afternoon as diurnal heating results in modest destabilization. Storm intensity will generally be limited by weak deep-layer shear, but brief gusty outflow winds up to 50 mph could accompany storms. The most widespread coverage will occur over the central Idaho mountains, while isolated convection will extend westward into eastern Oregon later this afternoon and evening.

By Wednesday, a general eastward disposition in moisture will occur towards south-central Idaho, with the isolated thunderstorm threat generally confined to the central Idaho Mountains and near the Idaho- Nevada border. High temperatures in the 80s will also make a return in the Snake Plain. The thunderstorm threat trends down further on Thursday while temperatures tick up a few more degrees.

LONG TERM /Friday through Tuesday/

Issued 219 AM MDT TUE JUN 30 2026 A persistent and steady warming trend will define the second half of this week, as flow aloft weakens while heat expands across much of the western United States. Broad westerly flow aloft will feature a couple weak disturbances which will promote isolated showers and thunderstorms over the higher terrain of Idaho on Friday. However, most of the lower elevations in Idaho, and all of eastern Idaho, are expected to be dry on the 4th of July as a building ridge across the northern Great Basin reduces any potential for thunderstorms, despite sufficient moisture. The first 90 degree temperatures of the week are also expected on Saturday in many lower elevation areas, increasing to the mid-90s by Sunday. Isolated showers and thunderstorms return to the higher terrain Monday and Tuesday as southwest flow aloft strengthens again, but hot temperatures will continue. is

AVIATION /12Z Tuesday through Wednesday/

Issued 542 AM MDT TUE JUN 30 2026 VFR. Isolated showers and thunderstorms Tue/PM, mainly over the ID W- Central mtns and near the ID/NV border. Thunderstorms capable of 30 kt outflows. Surface winds: Light and variable this morning, 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 this morning then NW 5-10 kt Tue afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.