textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Afternoon rain and snow showers over higher terrain through Tuesday.

- Temperatures below normal through Monday then warm to above normal by Thursday.

SHORT TERM /Through Tuesday Night/

Issued 247 PM MDT SUN APR 26 2026 A cool upper level trough remains over the area keeping temperatures below normal through the short term. A pair of shortwaves will move through the area, helping to enhance showers across eastern OR and thunderstorms over the higher terrain during the afternoon Monday. Drier air moves into the area on Tuesday with high clouds moving over the area. Temperatures will slowly moderate each day.

LONG TERM /Wednesday through Sunday/

Issued 247 PM MDT SUN APR 26 2026 Recent numerical model runs have the upper-level trough sticking around now through Thursday morning with another subtle shortwave moving through central Idaho. Northerly flow aloft will stick around until this feature moves through the flow. This feature will bring a 20-30% chance of showers to the mountains, with dry conditions elsewhere. An upper-level ridge builds quickly in behind this shortwave moving out, with weak west/southwesterly flow aloft. Temperatures through the period will steadily climb; with temperatures starting near normal on Wednesday, 5-10 degrees above normal Thursday, and 10-15 degrees above normal by Friday. The ridge will also bring dry conditions and light winds. Forecast confidence decreases over the weekend, as an upper-level trough will approach the West Coast, weakening 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 10-15% chance of thunderstorms.

AVIATION /00Z Monday through Tuesday/

Issued 552 PM MDT SUN APR 26 2026 VFR with SCT-BKN cumulus clouds over most areas through the evening. Snow levels 4500-5500 ft MSL. Scattered showers will return over higher terrain Monday afternoon, with isolated thunderstorms over SE OR near KBKE and KONO. Surface winds: W-NW 10-20 kt with gusts 20-30 kt this evening, with strongest winds east of KBOI. Winds will become variable or SW 5-15 kt tonight after sunset. Winds aloft at 10kft MSL: W-NW 15-25 kt.

KBOI...VFR. Surface winds: NW 10-15 kt with gusts 20-25 kt this evening, lowering down to 7-12 kt after sunset, then light and variable overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.