textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Warm and dry conditions through Tuesday with high temperatures 5 to 15 degrees above normal.

- Chance of precipitation increases Wednesday through Friday with cooler temperatures by the end of the week.

SHORT TERM /Through Monday Night/

Issued 244 PM MDT SAT OCT 17 2026 The area will remain positioned under a dry west to southwest flow through Monday. Sunday will see temperatures a few degrees cooler and lighter winds in the wake of a passing upper trough. Looking upstream, a Gulf of AK low will drop south along the coast on Monday. The model guidance remains consistent in keeping the closed low offshore as it passes our latitude on its way south. Increased southerly flow will return temperatures to 10-15 degrees above normal, similar to today (Sat). The flow aloft will also result in gusty afternoon winds across open/elevated terrain which will overlap with low afternoon relative humidity across SE Oregon.

LONG TERM /Tuesday through Saturday/

Issued 244 PM MDT SAT OCT 17 2026 The closed low will slow its southern progression off the central/southern CA coast on Tuesday, as a northern trough approaches the BC, Canada coast. Slight cooling aloft and increased cloud cover will take 3 to 5 degrees of high temperatures on Tuesday. Models are showing marginally favorable convective parameters over the w-central Idaho and eastern Boise Mtns, which are covered by a 20-30% chance of showers for Tuesday afternoon. The closed low turns east, then northeast Wed-Fri as it gets picked up by the northern stream trough tracking along the US/Canada border. Most areas see a chance of precipitation during this period, through the track of the low continues to favor SW Idaho zones with the greatest coverage and amounts. The heaviest rainfall (and mtn top snowfall) totals remain focused over w-central Idaho with widespread 0.25-0.50 inch amounts and locally up to 0.75 inches for Thur/Fri. Snow levels will drop from 9-10kft MSL Wed/Thur to 6-8kft MSL on Friday as the wrap around precipitation ends. Friday and Saturday are the coolest days as the low lifts through northern Utah and into SE Idaho.

AVIATION /00Z Sunday through Monday/

Issued 557 PM MDT SAT OCT 17 2026

VFR under thin high clouds. Locally reduced visibility due to smoke from wild/prescribed fires across the region. Patchy fog developing near KBNO and KBKE Sun/AM. Surface winds: variable up to 10 kt. Winds aloft at 10kft MSL: SW 10-20 kt.

KBOI...VFR. Smoke layers reducing visibility in the Treasure Valley and Boise foothills this evening. Surface winds: variable or light NW before sunset, transitioning to light SE overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.