Marine Weather and Tide Forecast for Boise City, ID

KEY MESSAGES
- Above normal temperatures into next weekend.

- Isolated PM showers and thunderstorms 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 Wednesday Night/
Issued 346 AM MDT MON MAY 4 2026 Interesting pattern over the region, with a high-over-low along the West Coast and deepening trough east of the Continental Divide. Our region will remain on the edge of/in-between these features. Moisture aloft will continue to converge along the northern NV border as southerly flow around the low meets a strengthening northerly flow associated with the northern high and deepening trough. Forecasts have been trending toward the drier northerly flow winning this battle, which is supported by overnight water vapor satellite imagery. The result is a lower chance of precipitation (15-25%) from the ID/NV border through the western Magic Valley and Boise Mtns for today. While cumulus buildups and an isolated shower/storm could be seen further north and west, the dry air and mid-level warming from the northern high will likely be too much, especially west of the ID/OR line. Gusty winds and brief heavy rain are possible from storms that develop. Outside of showers/storms northerly winds will ramp up this afternoon, then more so on Tuesday as widespread gusts of 30-40 mph set in. The prolonged period of gusty winds could bring blowing dust to SE Oregon and portions of the Snake Plain. Wednesday is dry and less windy as the northern high expands across the West. Tuesday and Wednesday are the coolest days of the week, with high temperatures dropping to within 5-10 degrees of normal.

LONG TERM /Thursday through Monday/
Issued 346 AM MDT MON MAY 4 2026 The upper-level ridge building into the Western U.S. will continue to move overhead Thursday into midday Friday, providing mostly dry conditions and above normal temperatures.
An upper-level shortwave will disrupt this briefly Friday PM into Saturday, moving east/southeast through the Southern Canadian provinces / Pacific NW into the Intermountain West and lee side of the Rockies. This will cause cloudier skies, precipitation chances (10-20% chance of showers over high terrain in southwest Idaho and southeast Oregon), and still above normal (but slightly cooler compared to Thursday)
temperatures. Once this feature moves further east/southeast late Saturday, another upper-level ridge builds in over the Western U.S., with this lasting into at least early the next week. Some clusters / ensembles have this upper-level ridge as particularly intense, enabling the potential for the lower Snake River Plain temperatures to reach the upper 80s and possibly even 90F (10-20% chance in the Boise area of 90+F).

AVIATION /12Z Monday through Tuesday/
Issued 520 AM MDT MON MAY 4 2026

VFR with with mostly clear skies through morning. Patchy valley smoke in the Boise Mountains. Isolated showers/thunderstorms will return mainly over NV border and high terrain of SW ID in the afternoon/evening. Surface winds: variable up to 10 kt through morning, becoming W-NW 10-20 kt with gusts to 25 kt in the afternoon. Winds aloft at 10k ft MSL: NW-NE 10-20 kt.

KBOI...VFR with clear skies. Surface winds: variable less than 7 kt through morning, becoming NW 8-13 kt with gusts up to 20 kt in the afternoon.

BOI WATCHES/WARNINGS/ADVISORIES
ID...None.

OR...None.