textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- High pressure will continue to build across the region through the weekend, leading to a significant warming and drying trend.

- Cooler more seasonal conditions expected next week.

SHORT TERM /Through Sunday Night/

Issued 201 PM MDT FRI APR 3 2026 Dry northwesterly flow continues across southeast Oregon and southwest Idaho this evening as the previous trough exits. An upper level ridge centered off the coast will continue to shift eastward, becoming the dominant weather feature through the end of the weekend. This transition will result in a pronounced warming trend, with afternoon high temperatures climbing to around 5 to 10 degrees above normal by Sunday. For tonight, clear skies and diminishing winds will support efficient radiational cooling. Enough residual moisture exists in the deeper mountain valleys of the West Central Idaho and Boise Mountains to allow for patchy fog development late tonight and early Saturday morning. Lows will once again be chilly, dipping into the 30s for most valley locations and teens in the higher elevations.

Saturday and Sunday will see plenty of sunshine as the ridge axis moves overhead. The airmass will remain stable with light surface winds, generally under 10 mph. Highs on Saturday will reach the mid 60s in the lower valleys, warming further into the low to mid 70s by Sunday afternoon. Lows Sunday night will be less biting than previous nights as the airmass moderates, generally staying in the upper 30s to low 40s in the valley. No precipitation is expected through the period.

LONG TERM /Monday through Friday/

Issued 201 PM MDT FRI APR 3 2026 Monday and Tuesday, high pressure remains in place with dry conditions, warm temps, and clear weather. Tuesday evening, precipitation chances increase as a strong low moves down the Canadian West Coast into the region. While the center of the low stays north of the US border, moist flow aloft from the Canadian system as well as a closed low off the CA coast supply just enough fuel for showers to develop. Coverage will be limited Tuesday through early Wednesday, but snow levels during this time fall from 7-8 kft MSL to 5-7 kft MSL. Wednesday evening through Thursday, the CA low moves inland, increasing precipitation chances further in the colder airmass. Snow showers in mountains and rain showers in valleys have a 20-30% chance of precipitation across the area during this period. The increasingly unsettled conditions continue into Friday as a semi-stalled trough remains over the region behind these systems. More lows funnel down from the Gulf of Alaska, leading to consistent days of active precipitation. Temperatures during this time drop from the 10-15 degrees above normal Monday/Tuesday to near normal by Wednesday.

AVIATION /06Z Saturday through Sunday/

Issued 1132 PM MDT FRI APR 3 2026

Mainly VFR under clear skies. Patchy mountain valley fog in the morning. Surface winds: variable less than 10 kt. Winds aloft at 10kft MSL: NW 5-10 kt.

KBOI...VFR. Surface winds SE 4-8 kt overnight, then NW Saturday afternoon.

Sunday Outlook...VFR, high clouds. Patchy mountain valley fog Sunday morning. Surface winds less than 10 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.