textproduct: Boise

KEY MESSAGES

- Hot temperatures through the week, potentially becoming very hot next weekend.

- Isolated to scattered showers and thunderstorms through Tuesday, with lightning, gusty outflow winds. - Breezy winds each afternoon.

SHORT TERM /Through Tuesday Night/

An upper trough kicking out of CA this afternoon will track through the region late tonight into Monday. Daytime heating will support shower and thunderstorm development this evening across SE Oregon. The dry surface environment will favor gusty outflow winds with potential speeds to 50 mph. Not expecting these to be long reaching outflow boundaries with the strongest winds impacting southern Harney and Malheur counties. A slight chance of thunderstorms extends into Idaho overnight as the upper low tracks overhead. Given the dynamics and instability aloft, have wrapped the Snake Plain into this potential as well. The shower and thunderstorm threat continues through the day Monday, with the focus of afternoon initiation over higher terrain. Storm motion will direct activity into the Snake Plain, but model soundings show unfavorable conditions for maintaining activity. Increasing moisture brings the chance for brief heavy rain along with gusty outflow winds. Drier air will push into the region on Tuesday, cutting of precipitation potential for SE Oregon, with a slight chance lingering across higher terrain south of the Snake Plain.

LONG TERM /Wednesday through Sunday/

Westerly flow shunts the moisture to the east on Wednesday and Thursday with dry and breezy conditions and slightly cooler temperatures as the ridge is temporarily suppressed. Temperatures cooling to near normal on Thursday. The ridge expands over Utah on Friday bringing warmer temperatures for next weekend. Monsoonal moisture increases significantly on Sunday with precipitable water values around the 95th percentile. Shower and thunderstorm chances increase on Sunday but are currently not reflected in the forecast.

AVIATION /18Z Sunday through Monday/

Issued 1203 PM MDT SUN JUL 5 2026 Mainly VFR. High density altitude due to heat. Isolated thunderstorms developing late this afternoon and evening over central ID mountains and along the NV border in OR and ID moving north overnight. Thunderstorms capable of producing outflow gusts up to 45 kt. Surface winds: W-NW 5-15 kt, with gusts 15-25 kt late this afternoon and evening. Winds aloft at 10kft MSL: S-SW 10-20 kt.

KBOI...VFR. Increasing clouds, a 10-20 percent chance of showers and thunderstorms overnight. High density altitude due to heat. Surface winds: NW 5-10 kt with gusts up to 20 kt this afternoon. Variable outflow winds overnight with gusts up to 25kt from showers and storms.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...Red Flag Warning until 9 PM PDT this evening for ORZ670>672.