textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Near record temperatures continue through Wednesday, with valley highs in the mid 70s.

- Gusty winds and very dry conditions will bring elevated fire danger near the Nevada border on Tuesday and Wednesday afternoon.

- Mountain showers and slightly cooler temperatures will occur following a cold frontal passage Wednesday through Friday.

SHORT TERM /Through Wednesday Night/

Issued 212 PM MDT MON MAR 23 2026 The upper level ridge will briefly return tonight through Tuesday in response to a developing trough off the British Columbia coast. Temperatures will climb to nearly 10-15 degrees above normal by Tuesday, with valley highs reaching the mid 70s. A chance (20-30%) for showers exists across the higher terrain of Baker County and the west central Idaho mountains Tuesday ahead of the approaching cold front. Breezy to gusty winds will occur over the region, with the strongest winds up to 50 mph over southeast Oregon near the Nevada border. These gusty pre- frontal winds combined with single-digit afternoon relative humidity values will bring heightened fire danger to the lower elevations near the Oregon- Nevada border.

Temperatures will be closer to normal across much of southeast Oregon Wednesday but remain well above across Southwest Idaho as the front slowly moves southeasterly across the area. Temperatures will cool significantly overnight on Wednesday, with snow levels lowering from above 8000 feet MSL to 4000-5000 feet MSL by the end of the precipitation. Light snow showers above about 5000 feet will bring minor snow accumulation to higher elevations over northern Valley County Wednesday night.

LONG TERM /Thursday through Monday/

Issued 212 PM MDT MON MAR 23 2026 The primary story for the long term period is the rebuilding of a strong upper level ridge over the Western US. This feature will initiate a significant warming trend starting Thursday. Deterministic models and ensembles are in good agreement that the ridge axis will be centered over the Great Basin by Saturday. This pattern is similar to the typical four-corners ridge seen in the summer. High temperatures will climb into the 70s for most valley locations Friday and Saturday, which is roughly 10 to 15 degrees above normal for late March.

By Sunday and Monday, the ridge begins to break down with the axis shifting eastward as a series of disturbances pass well to the north. This will result in slightly breezy conditions and an increase in cloud cover, but temperatures should remain mild. This has the potential to bring moisture from the southwestern US though as some guidance suggests. At the moment though, dry conditions are favored to persist through the end of the period for all but the highest terrain near the Nevada border.

AVIATION /00Z Tuesday through Wednesday/

Issued 542 PM MDT MON MAR 23 2026 VFR. Isolated rain showers Wednesday morning, with areas of mountain obscuration north of KBNO-KONO-KSUN. Variable surface winds up to 10kt tonight, shifting to SW-SE 10-20kt Tues afternoon with gusts up to 30kt in eastern OR. Winds aloft at 10 kft: W-SW 20-30 kt increasing to W-SW 35-50kt by 21z/Tues.

KBOI...VFR. Isolated rain showers Wednesday morning. Surface winds NW 5kt this evening, becoming SE 5-10kt after sunset.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.