textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Above normal temperatures through next weekend with Tuesday and Friday being the hottest days. - The hot temperatures Tuesday and Wednesday will be accompanied by gusty winds and very dry conditions.

- A chance of showers and thunderstorms returns to the area Friday and Saturday.

SHORT TERM /Through Wednesday Night/

Issued 240 PM MDT MON JUN 15 2026 The heat will reach its peak on Tuesday with high temperatures into the mid-90s across the lower Snake Plain. A few sites could close in on 100F along the ID/OR border and around Hagerman in the Snake Plain. Winds ramp up Tuesday afternoon reaching 15 to 25 mph with gusts 30 to 40 mph. A passing upper wave will bring a weak front across the area Tuesday night, and the post frontal pressure gradient will maintain breezy winds along the I-84 corridor through the night. While Tuesday is dry (precipitable water values in the 40th %tile), even drier air will move in behind the front on Wednesday (PW drops to 5th %tile). Winds remain gusty across the Snake Plain in response to a deepening surface low over eastern ID. Areas from Mountain Home to Twin/Jerome will see to around 40 mph Wednesday afternoon and evening. Similar to Tuesday the dry and windy pattern will result in critical fire weather conditions in the s-central Snake Plain. Wednesday is 5-10 degrees cooler, though still about 5 degrees above normal.

LONG TERM /Thursday through Monday/

Issued 240 PM MDT MON JUN 15 2026 As the high pressure ridge builds, temperatures climb Thursday and Friday up to 10 to 15 degrees above normal by Friday. This will make Friday very comparable to the hot temperatures forecast for tomorrow. The heat on Friday will bring very low afternoon 5 to 10% minimum RHs across the area, especially in lower elevations.

As the dry heat settles in, an upper level trough will move into the area for the weekend. While it will introduce some slightly cooler temperatures, it will also bring a chance of precipitation. Thunderstorms in Southeast Oregon and along the Idaho-Nevada border Friday evening pose a critical fire weather threat, and could produce outflow winds up to 40 mph based on long range forecast soundings. Behind the main trough axis, winds are forecast to ramp up across the upper Snake River Plain over the weekend. Showers and thunderstorms move into Idaho on Saturday. Temperatures begin to climb again next Monday as a ridge builds behind the trough.

AVIATION /00Z Tuesday through Wednesday/

Issued 545 PM MDT MON JUN 15 2026

VFR with high clouds moving in this evening. Hot temperatures will cause high density altitudes across the area Tuesday afternoon. Surface winds: W-NW 5-15 kt, becoming light and variable overnight. Winds aloft at 10kft MSL: NW 10-20 kt. KBOI...VFR. High density altitude Tuesday afternoon. Surface winds: NW 6-10 kt with periodic gusts up to 18 kt possible through sunset, becoming light and variable overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.