textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Widespread subfreezing temperatures again tonight. - Drier and warmer through Tuesday.

- Cooler and unsettled late Tuesday into Wednesday with valley rain and mountain snow.

SHORT TERM /Through Sunday Night/

Issued 204 PM MDT FRI APR 17 2026 A ridge of high pressure will build into the area over the next several days with a warming trend each day through Monday. Temperatures will warm around 10 degrees on Saturday and an additional 10 degrees on Sunday. As the ridge strengthens, the surface winds shift to south-southeast aiding in the warming as well with breezy conditions during the afternoons through Monday.

LONG TERM /Monday through Friday/

Issued 204 PM MDT FRI APR 17 2026 A closed low will reside along the West Coast early next week, pulling warm southerly air into SE Oregon and SW Idaho. This flow pattern will continue unseasonably warm temperatures 10-15 degrees above normal on Monday. Tuesday will continue to see temperatures 10- 15 degrees above normal, but with some confidence uncertainty in temperature maximums. Precipitation will begin to increase across E Oregon late Tuesday as the center of the low shifts inland and gets gradually swallowed by a longwave trough steering over British Columbia. This merging system will generate breezy surface winds and widespread precipitation over the area Wednesday and Thursday. Wednesday will see the highest likelihood of precipitation at 50-80% for the area. High mountain snow will accumulate as snow levels lower to 5000-7000 ft MSL. A cooling trend from this system will return temperatures back to near-seasonal normals Wednesday to Friday. By Friday, latest long-range guidance suggests a relatively dry shortwave trough breaking off from the merged low and digging into our area and the Great Basin. Overall precipitation is expected to taper off by late Friday, with mainly mountain areas seeing a 20-30% chance of showers from remnant moisture.

AVIATION /00Z Saturday through Sunday/

Issued 530 PM MDT FRI APR 17 2026

VFR. Cumulus over the mountains will clear through the evening. Increasing high clouds overnight. Surface winds: variable less than 10 kt. Winds aloft at 10kft MSL: W-NW 5-15 kt.

KBOI...VFR with mostly clear skies. Surface winds: NW 5-10 kt through mid evening, shifting to the SE 6-12 kt overnight.

Weekend Outlook...VFR. Dry with periods of high cloud cover. Local mtn valley fog Saturday morning. Surface winds S-SE 5-15 kt Saturday increasing to 10-20 kt with gusts 20-30 kt on Sunday, with strongest winds in Snake Plain east of KBOI. E-SE or variable under 15 kt Sat/Sun night.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Freeze Warning from midnight tonight to 10 AM MDT Saturday for IDZ012-014-016. OR...Freeze Warning from midnight MDT /11 PM PDT/ tonight to 10 AM MDT /9 AM PDT/ Saturday for ORZ064.