textproduct: Boise

KEY MESSAGES

- Above normal temperatures through next week.

- Isolated PM 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/

A ridge of high pressure will build over the Western US and British Columbia, bringing temperatures 10-15 degrees above normal to the region through the short term period. A low pressure system will move onshore over California today, bringing a push of showers and thunderstorms near the Nevada Border and over high terrain in Baker/Valley Counties. This low will then migrate east, continuing the chance of afternoon showers and thunderstorms (20-30% chance) to the areas near the Nevada border on Monday and Tuesday. Very dry air near the surface, shown in inverted-V forecast soundings, will limit precipitation from these showers and thunderstorms. Wind and lightning will therefore be the primary hazards, with outflow gusts up to 40-50 mph from any of the strongest showers/thunderstorms. These gusts will also bring patchy blowing dust, especially near dry lake beds in Eastern Oregon. Winds will increase on Tuesday with northerly flow strengthening over the region. The highest winds will be seen in Eastern Oregon with sustained northerly winds around 15-25 mph with gusts up to 40 mph, with ridgetops seeing strong winds up to 45 mph.

LONG TERM /Wednesday through Sunday/

The ridge of high pressure will continue to amplify over the region through the work week, bringing mostly dry conditions and above normal temperatures through Friday. A shortwave passage over Montana-Wyoming late Wednesday into Thursday will increase potential for mountain showers and thunderstorms in southwest Idaho, but confidence is low (<10% chance). Another shortwave will quickly move in from the west on Friday. This will bring a slight reduction in temperatures (about 5 degrees cooler) on Saturday, with a 10-30% chance of showers over high terrain in southwest Idaho and southeast Oregon. High pressure will then rebuild over the West on Sunday, bringing the potential for Treasure Valley temperatures to reach the upper 80s and maybe even 90F (5-10% chance in Boise area).

AVIATION /18Z Sunday through Monday/

Issued 1147 AM MDT SUN MAY 3 2026

VFR. Patchy valley smoke in the Boise Mountains tonight. Isolated showers and thunderstorms this afternoon over SE OR and high terrain in SW ID. Gusty and erratic outflow winds up to 40 kt with blowing dust are likely near showers and thunderstorms. Surface winds: NW-NE 5-15 kt, becoming W-NW 10-20 kt with gusts to 30 kt Mon/PM. Winds aloft at 10k ft MSL: NW-NE 15-30 kt.

KBOI...VFR. Surface winds: NW 6-10 kt shifting to variable less than 6 kt overnight.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.