textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Temperatures 15 degrees above normal Friday, lowering to 5 degrees above normal Saturday and Sunday, then warming to 10-15 degrees above normal next week.

- Scattered showers and thunderstorms late Friday through Saturday.

- Showers and storms capable of producing strong and erratic outflow winds Friday, and gusty winds, heavy rain and small hail on Saturday afternoon.

SHORT TERM /Through Sunday Night/

Issued 407 AM MDT FRI JUN 19 2026 A ridge remains over the area, with a weak trough over northern CA. A couple of thunderstorms have continued most of the night into this morning in northern CA. Temperatures will be around 15 degrees above normal today with increasing clouds this afternoon. This system will slowly move over the Great Basin through Saturday and into eastern ID and southwest MT on Sunday. Shower and thunderstorm chances increase along the NV border this afternoon and evening, with gusty outflow winds possible in eastern OR. The system moves northward on Friday night with scattered showers and isolated thunderstorms overnight. The system moves overhead on Saturday and east by the afternoon with mostly cloudy skies. Daytime heating will enhance thunderstorms on Saturday afternoon, especially in eastern OR and southwest ID south of Burns to Boise, behind the main system where partial clearing will lead to destabilization. Temperatures lower to around 5 degrees above normal Saturday and Sunday.

LONG TERM /Monday through Friday/

Issued 407 AM MDT FRI JUN 19 2026 A ridge will expand over the West on Monday with warm temperatures through at least Wednesday. Temperatures will be 10 to 15 degrees above normal with values near 100F for the first time on Tuesday and Wednesday. Forecast confidence is low beyond Wednesday with the handling and timing of a Gulf of Alaska low pressure system moving into the Pacific Northwest versus the ridge continuing and the evolution of that. A 10-20 percent chance of showers and thunderstorms in this transition, but current forecast favors dry. Eventually by next Friday, cooler northwest flow sets up over the Pacific NW with temperatures returning to near normal with breezy conditions.

AVIATION /12Z Friday through Saturday/

Issued 552 AM MDT FRI JUN 19 2026 VFR. Showers and thunderstorms developing late afternoon near NV border. Storms capable of erratic outflow gusts 40-50 kts, small hail, and lightning. High density altitude Friday afternoon. Surface winds: variable 10kt, except outflow winds from south-southwest this evening. Winds aloft at 10kft MSL: W-NW 10-20 kt.

KBOI...VFR. Surface winds: variable 5-10 kt. Isolated showers overnight which may produce variable gusty winds 10-20kt.

Weekend Outlook...VFR. Scattered MVFR showers in the morning with isolated to scattered thunderstorms Saturday afternoon. Storms capable of producing gusty winds, small hail, blowing dust, and brief heavy rain. Mountain obscuration Saturday morning through late afternoon. Breezy west-northwest winds Saturday afternoon. Clearing skies Sunday with breezy northwest winds through the Snake Plain.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning from 6 PM this evening to noon MDT Saturday for IDZ423-426. OR...Red Flag Warning from 1 PM this afternoon to 5 AM PDT Saturday for ORZ670-672.