Fairfield, ID Weather

Update

Updated aviation discussion.

Key messages

- Continued dry with normal temperatures through Friday morning.

- Precipitation chances increasing across higher terrain on the Idaho side Friday, becoming widespread in in ID and OR Saturday afternoon through Sunday.

- Drying and warming Monday through Thursday, then turning cooler and wetter Thursday and beyond.

.SHORT TERM /Through Sunday Night/: Issued 204 PM MDT THU OCT 29 2026 Upper low center off the WA coast will hold stationary through Saturday evening but the low will elongate southward down the coast during that time. Subtropical Pacific moisture off Baja California will enter the south end of the low beginning Saturday and be drawn northward through the Great Basin along and ahead of a developing eastward-moving surface cold front. The front will become a focus for moderate to heavy pcpn as it moves across our CWA Saturday night through Sunday. Eastern OR will become wet before sunset Saturday, but rain may hold off in western ID (including the BOI metro) until around 7 PM MDT Saturday evening, after which several hours of steady pcpn will fall. SPC has a slight chance of thunderstorms in south-central ID Saturday night, which we have also included in our forecast. Accumulating snow will stay above 6500 feet while the bulk of pcpn is falling.

.LONG TERM /Monday through Friday/: Issued 204 PM MDT THU OCT 29 2026 Showers will continue through Sunday, tapering off throughout the day as the system departs. Snow levels Sunday will have lowered to 5.5-7kft MSL (increasing from west to east). These snow levels are higher than previous model runs consistent with a faster system trend. Snowfall will likely be limited to the mountains Sunday through Monday morning. In areas below the snow level less than 0.1 inches of rain is forecast, with only a trace to 0.03 inches forecast in the lower valleys. Sunday afternoon and evening will feature gusty winds following the cold frontal passage, with west to northwest gusts of 20-40 mph in the Snake River Plain.

Beginning Monday, the area will be dry with a warming trend through Thursday, although seasonable temperatures are anticipated throughout. Fog and stratus is possible Monday and Tuesday mornings with the recent precipitation and at the beginning of the warming trend. While there will be multiple opportunities for weak shortwaves to pass over the area, moisture will be limited and the shortwaves will just result in periods of increased high clouds.

.AVIATION /06Z Friday through Saturday/: Issued 1203 AM MDT FRI OCT 30 2026 Generally VFR with overcast skies through the early morning. Light rain will move in from the south this morning, with MVFR ceilings in higher terrain. A 30% chance of thunderstorms exists in the Magic Valley this afternoon. Mountains obscured in precipitation. Surface winds: SE-SW 5-15 kt with occasional afternoon gusts to 20 kt. Winds aloft at 10kft MSL: SW-S 15-25 kt.

KBOI: VFR. Light rain moving in from the south early this morning. Surface winds: E-SE 5-15 kt.

Weekend Outlook: Isolated to scattered showers Sat/AM, becoming widespread Sat/PM. Precipitation continuing through Sunday, tapering off from W-E through the afternoon. VFR-MVFR in rain showers, IFR- LIFR in mountain snow. Mountain obscuration this weekend. Snow levels: 6.5-8.5 kft MSL Saturday, lowering to 5.5-6.5 kft MSL Sunday. Surface winds: SW-SE 5-15 kt Saturday, then W-NW 10-20 kt with gusts to 20-30 kt behind a cold front Sunday.

Watches, warnings and advisories

ID: None.

OR: None.