textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Afternoon rain and snow showers over higher terrain through Tuesday

- Gradually warming temperatures through the forecast

SHORT TERM /Through Tuesday Night/

Issued 251 AM MDT SUN APR 26 2026 A very slow moving upper trough will keep weather cooler and unsettled as it moves eastward. Each afternoon today through Tuesday, marginal moisture and instability will support scattered showers in higher terrain of Eastern Oregon, Central Idaho, and the southern highlands. Enough afternoon instability will be present for stray lightning in showery areas. Most of the system's moisture will be northeast and south of us, increasing precipitation chances just outside our forecast area. Heights and thickness values rise as the system moves east, bringing a gradual warming trend. Temperatures about 5 degrees below normal today rise to near normal by Tuesday, and continue to climb in the long term.

LONG TERM /Wednesday through Sunday/

Issued 251 AM MDT SUN APR 26 2026 A final weak shortwave impulse will move across the area on Wednesday as the parent longwave trough over the Upper Midwest moves east. This feature will bring a 20-30% chance of showers to the mountains with dry conditions elsewhere. Temperatures will be near to slightly above normal. A broad upper level ridge will move over the region Thursday and Friday, continuing the warming trend. Highs by Friday will be nearly 10 degrees above normal, reaching the mid 70s in lower elevations. The ridge will also bring dry conditions and light winds. Forecast confidence decreases over the weekend as an upper level trough approaching the West Coast weakens the ridge. Ensembles vary considerably on the track and strength of the trough. For now, temperatures are favored to remain 10-15 degrees above normal, but could trend cooler if the trough is stronger and moves overhead. Precipitation chances tick up over the weekend, reaching 10-30% by Sunday with a 10% chance of thunderstorms.

AVIATION /12Z Sunday through Monday/

Issued 540 AM MDT SUN APR 26 2026

Mainly VFR. Light rain showers in the Magic Valley will decrease by mid morning. Isolated to scattered rain and snow showers will develop over the higher terrain this afternoon. Localized MVFR/IFR conditions and mountain obscuration in showers. Snow levels 4500-5500 ft MSL. Surface winds: W-NW less than 10 kt this morning, increasing to 10-20 kt with gusts 20-30 kt this afternoon through sunset, strongest east of KBOI. Winds aloft at 10kft MSL: W-NW 15-25 kt.

KBOI...VFR. Surface winds: variable under 7 kt this morning, becoming NW 10-15 kt with gusts 20-25 kt this afternoon. Winds subsiding by mid evening, becoming light and variable overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.