textproduct: Boise

KEY MESSAGES

- Temperatures will remain above normal through Tuesday.

- A slight chance of showers and thunderstorms will develop this afternoon and evening across east-central Oregon and west- central Idaho.

- A dry cold front on Tuesday will bring breezy winds, with temperatures cooling 5-10 degrees by Wednesday.

- A wetter pattern will develop late in the week into the weekend.

SHORT TERM /Through Wednesday Night/

The upper level ridge axis that brought unseasonably warm temperatures to the region will shift east tonight as the next system approaches from the northwest. Low temperatures will remain mild, generally in the upper 30s to mid 40s in the lower valleys.

On Tuesday, a more potent upper level trough will move east across southern Canada, pushing a dry cold front through our area. While this front lacks significant moisture, it will tighten the pressure gradient across the region. Northwesterly wind gusts of 20 to 35 mph will develop in the afternoon and evening, with stronger gusts possible on ridgelines. These breezy winds, combined with lowering relative humidity values, will result in increased fire danger across portions of southeast Oregon and southwest Idaho. Additionally, weak instability ahead of and along the front will support a 20 percent chance of showers and thunderstorms. This activity is expected to be focused mainly along the Idaho/Nevada border during the afternoon and evening hours. High temperatures on Tuesday will be slightly cooler in the north, while southern areas remain warm until the frontal passage.

By Wednesday, temperatures will cool 5 to 10 degrees as the grazing shortwave exits to the east and flow switches to the northwest. Winds will begin to subside but remain breezy in the afternoon with gusts of 15 to 25 mph. Moisture ahead of an approaching low off the California coast will bring a 20 percent chance of showers to the Oregon and Nevada border late Wednesday.

LONG TERM /Thursday through Monday/

A warm an active pattern will arrive in the long-term period. Our area will be set in between two systems come Thursday, with the main jet stream north and a closed low off of the coast of California. Southerly flow associated with the low will maintain temperatures near 10 degrees above normal. As the California low slowly moves east, Pacific moisture advecting around it will allow for increasing chances of precipitation. Thursday afternoon, precipitation chances will increase to 15-35% near the Idaho/Nevada border and southeast Oregon. Come Friday afternoon, precipitation chances increase to 30-70% nearly area- wide. With afternoon destabilization supporting a 10-15% chance of thunderstorms. Saturday appears to be the most active day, as the low continues to move inland, precipitable water values increase to above the 90th percentile of climatology. Precipitation chances will increase to 40-75% area-wide. There are hints of a shortwave in the main jet stream north as well, which could interact with this moisture and provide additional forcing for ascent. This pattern is typically supportive of thunderstorms. Ensemble guidance has instability building in with mean CAPE values around of 200-250 j/kg, which will supports the threat as well. For now will keep thunder chances Saturday afternoon 15-20%.

Temperatures will cool down to near normal come Sunday, as the California low and reinforcing shortwave make their way over our area. Precipitation chances will remain elevated (40-75%) through Sunday as the system moves through. Snow levels will be at 8000+ ft MSL through the long term, dropping to 4500-6500 ft Monday.

AVIATION /18Z Monday through Tuesday/

Issued 1153 AM MDT MON APR 6 2026

VFR under high clouds. Slight chance of showers (15-20% chance) and thunderstorms (10-15% chance) this afternoon in E-cntrl Oregon and W-cntrl Idaho near KBKE/KMYL after Mon/20z. Localized outflows of 20-30 kt near thunder and heavier showers. Surface winds: SW-NW 5-15 kt this afternoon becoming variable overnight. Then NW 10-15 kt with gusts to 20 kt late Tue/AM. Winds aloft at 10 kft MSL: W 5-15 kt.

KBOI...VFR with high clouds. Surface winds: NW 4-10 kt this afternoon, then light and variable leaning S-SE overnight. Becoming NW 7-12 kt late Tue/AM following a cold front.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.