textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Above normal temperatures through next week.

- Chance of afternoon/evening showers and thunderstorms Sunday through Tuesday, mostly along the NV border and across south- central Idaho.

- Windy Monday and Tuesday afternoon, especially in southeast Oregon and the Snake Basin in Idaho,

SHORT TERM /Through Tuesday Night/

Issued 343 AM MDT SUN MAY 3 2026 Have seen little change in the forecast with the track of a closed low off the West Coast and the deepening trough to our east. Instability and daytime heating will support a chance of afternoon and evening showers and thunderstorms along the NV border today. Saw some buildups over the mtns of Baker County and the w-central ID mtns yesterday afternoon and expect to see the same again today. Thus have bumped up shower/storm chances to 15-20% in these areas, and extended it into far northern Harney County. Gusty outflow winds are the mostly likely threat from showers/storms today, with speeds to 40 mph possible. The closed low will track through the southern Great Basin on Monday while a short wave trough drops south along the Continental Divide. Together, these features will increase precipitation chances to 30-40% along the NV border and across the eastern Boise Mtns and portions of the western Magic Valley. Northerly flow accompanying the shortwave trough will bring wind gusts of 25-40 mph Monday afternoon, mostly across SE Oregon and higher terrain of SW Idaho. A lingering shower/storm threat on Tuesday is focused over s-central Idaho on the backside of the eastward moving closed low and is covered with 15-30% precipitation chances. Winds will ramp up in the afternoon with gusts in the 25-40 mph range across open terrain. These winds could kick up dust, especially over drier portions of SE Oregon. Temperatures are 10-15 degrees above normal today and Monday, cooling 3-8 degrees on Tuesday.

LONG TERM /Wednesday through Sunday/

Issued 343 AM MDT SUN MAY 3 2026 An upper-level ridge will build in over the area Wednesday and Thursday. This pattern will enable warm temperatures to build in across the region, with high temperatures 10-15 degrees above normal both days. On Friday into Saturday, an upper-level shortwave of varying intensity (shown well in cluster analysis) will bring cloudier skies and precipitation chances 10-25% in higher terrain areas, especially the west-central Idaho mountains. After this feature moves out, another quite potent upper-level ridge looks to build in over much of the Western U.S. into the beginning of next week.

AVIATION /12Z Sunday through Monday/

Issued 520 AM MDT SUN MAY 3 2026

VFR. Patchy valley smoke in the West Central and Boise Mountains today. Isolated showers and thunderstorms this afternoon over SE OR and high terrain in SW ID. Gusty and erratic outflow winds with blowing dust are likely near showers and thunderstorms. Surface winds: variable under 10 kt through morning, then NW-NE 7-15 kt in the afternoon/evening. Winds aloft at 10k ft MSL: variable 5-10 kt.

KBOI...VFR. Surface winds: SE 5-10 kt through early morning, then NW 7-12 kt in the afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.