textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Windy this afternoon and tonight.

- Isolated afternoon/evening showers and thunderstorms today over the mountains of S Idaho and SE Oregon, otherwise dry.

- Above normal temperatures will continue, as much as 15-20 degrees above normal next Monday and Tuesday.

SHORT TERM /Through Friday Night/

Issued 207 PM MDT TUE MAY 5 2026 Isolated showers and thunderstorms (15-25 percent areal coverage) in and near the Magic Valley late this afternoon and evening as hi-res models show a distinct convergence zone there, and enough lift to generate clouds and pcpn. Models depict large scale northerly surface winds entering the Snake Basin through both Oregon and Montana and converging in the Magic Valley. The stronger portion from Montana will push the convergence zone westward overnight as a "back door" cold front, all the way past Boise by sunrise. The air from Montana is very dry, but tonight will be too windy to allow full radiational cooling once skies clear. Wednesday looks sunny, dry, less windy, and slightly cooler than today. Wednesday night should be clear, dry, and calmer, but by then the next warmer air mass will approach from the west, offsetting the better conditions for radiational cooling. So Wednesday night should be no cooler than tonight. Thursday looks sunny and 3 to 6 degrees warmer than Wednesday, and Thursday night looks clear and cool.

LONG TERM /Saturday through Wednesday/

Issued 207 PM MDT TUE MAY 5 2026 A brief cooldown will commence Friday into Saturday as a weak and dry cold front moves through the region. However, the heat will build early next week in association with a strong area of high pressure aloft over the western United States. Monday is currently forecast to see the hottest temperatures of the year so far, peaking at 15 to 20 degrees normal. Latest probabilities suggest a 50-80% chance of a high temperature above 90 degrees in the Snake Plain and over lower elevations of southeast Oregon. Tuesday will also be hot, though perhaps a few degrees cooler than Monday. Precipitation chances will be near zero throughout the period, with only a slight chance of showers on Saturday in the central Idaho mountains.

AVIATION /06Z Wednesday through Thursday/

Issued 1209 AM MDT WED MAY 6 2026 VFR. Scattered cumulus developing over the higher terrain in the afternoon. Localized smoke near fire activity. Surface winds: N-NW 5- 10 kt, becoming E-SE 5-15 kt from east to west overnight. Gusts 20- 30 kt through the Snake Plain. Winds in the afternoon becoming W-NW 5-15 kt with gusts to 20 kt. Winds aloft at 10kft MSL: N 15-30 kt, becoming W-NW 15-25 kt after Wed/18Z.

KBOI...VFR. Surface winds: NW 6-11 kt, becoming SE 8-15 kt after Wed/09Z with gusts 20-25 kt in the morning. Winds becoming NW 7-12 kt in the afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.