textproduct: Boise

KEY MESSAGES

- Scattered showers and thunderstorms late today through Saturday.

- Daytime temperatures cooling to normal Saturday and Sunday, then hotter and drier Monday through Wednesday.

SHORT TERM /Through Sunday Night/

As of 2 PM MDT thunderstorms were already developing along the NV/OR border and moving north. An upper trough in northern California tonight will move slowly ENE-ward across the northern Great Basin Saturday and into eastern ID and southwest MT Sunday. Shower and thunderstorm coverage will increase in southeast Oregon through this evening, and in southwest Idaho later tonight, continuing in both areas Saturday. Stronger storms will produce gusty outflow winds, especially in southeast OR late today and this evening. Storms should weaken during the overnight hours but become stronger again later Saturday. Low temperatures tonight will be warmer than normal, but highs Saturday and Sunday will be cooler than today, and close to normal for mid-late June. Lows Saturday night will be about ten degrees cooler than tonight but still slightly above normal. Lows Sunday night should be another 5-10 degrees cooler with clearer skies and drier air in place.

LONG TERM /Monday through Friday/

A ridge of high pressure will build over the West Coast beginning Monday, bringing a warming and drying trend to the region through the middle of the week. Valley high temperatures will reach the upper 90s to low triple digits by Wednesday. A shortwave trough will then move into the region late Wednesday into Thursday. This will bring slight cooling, breezy valley winds, and a low chance of showers and thunderstorms over high terrain on Thursday/Friday. Model variance remains high on the strength of the trough and the extent of moisture, but the best agreement exists for precipitation to stay over eastern Idaho. Long range models hint at a stronger closed low to move into the Pacific Northwest by late Friday, which would bring much cooler temperatures and precipitation for the end of the week.

AVIATION /18Z Friday through Saturday/

Issued 1159 AM MDT FRI JUN 19 2026

VFR. A line of high-based virga showers and thunderstorms will move from south to north over the NV border this afternoon through the late evening, with blowing dust, small hail, lightning, and gusty outflow winds up to 45 kt. Highest confidence in lightning and outflow winds will be south and west of the Snake River Valley and near KBNO. High density altitude this afternoon with very hot temperatures. Surface winds: W-NW 5-15 kt with gusts to 25 kt, then variable less than 10 kt overnight. Winds aloft at 10kft: SW-W 15-30 kt.

KBOI...VFR. A 20-30% chance of high based showers and outflow wind gusts up to 35 kt this evening. High density altitude this afternoon with very hot temperatures. Surface winds: W-NW 5-10 kt with gusts to 25 kt, then variable less than 10 kt overnight.

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 6 PM MDT Saturday for IDZ423-426. OR...Red Flag Warning until 5 PM PDT Saturday for ORZ670-672.