textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Mostly dry with temperatures 10 to 15 degrees above normal for Memorial Day weekend.

- Gusty winds arriving on Monday ahead of a cold front, resulting in elevated fire weather conditions.

- Much cooler with gusty winds and a chance of showers and thunderstorms Tuesday and Wednesday.

SHORT TERM /Through Saturday Night/

Issued 220 PM MDT THU MAY 21 2026 A ridge of high pressure will build over the area Friday and Saturday. Temperatures Friday will be about 5 degrees warmer than today, followed by another 5-10 degrees of warming on Saturday as the ridge moves overhead. This will place high temperatures 10-15 degrees above normal, with lower elevations reaching the mid to upper 80s. Conditions will remain dry, except for a 10-20% chance of showers and thunderstorms near the Nevada border as moisture lifts north with the building ridge. Winds will mostly be light, except for breezy conditions in the higher terrain Saturday afternoon.

LONG TERM /Sunday through Thursday/

Issued 220 PM MDT THU MAY 21 2026 Sunday and Monday see temperatures 10-15 degrees above normal as high pressure sits over the area. Afternoon minimum RHs are dry at 10-30%, increasing with elevation. The warm weather cools down Monday evening as a cold front moves through, part of a larger upper level low that sits over the area for a few days. The cold front brings wind gusts up to 45 mph Monday and Tuesday evenings. While Tuesday will be much cooler, the gusty winds, dry conditions, and warm temperatures support elevated fire weather risks Monday afternoon and evening. Making the forecast even trickier, each afternoon sees a 20-30% chance of thunderstorms through the long term as the low pressure keeps conditions unsettled. Best storm chances move from the NV border Sunday/Monday to Central ID Tuesday and most of SW ID Wednesday and Thursday. Temperatures gradually warm after Tuesday.

AVIATION /00Z Friday through Saturday/

Issued 532 PM MDT THU MAY 21 2026 VFR. Scattered high clouds moving in from northwest this evening. Surface winds: W-NW 10-15 kt, with gusts up to 25 kt, becoming mostly variable under 10 kt tonight after sunset.

KBOI...VFR with mostly clear skies. Surface winds: NW 10-15 kt with gusts up to 25 kt this evening, becoming S-SE 5-10 kt late tonight through Friday afternoon.

Weekend Outlook...VFR with mostly clear skies throughout the weekend. Winds SE or variable 5-10 kt in the night/morning and W-NW 5-15 kt in the afternoon each day. Some isolated afternoon thunderstorms possible near NV border each day.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.