textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- High temperatures Sunday will be 10 degrees below normal with rain and snow showers possible in the west-central Idaho mountains.

- Showers Tuesday and Wednesday will bring additional precipitation, mainly to the mountains.

- Warmer and drier after Thursday.

SHORT TERM /Through Monday Night/

Issued 240 PM MDT SAT JUN 6 2026 A unseasonably cool upper level trough will move into the Pacific NW tonight, bringing cooler temperatures and breezy conditions. Southwest Idaho and southeast Oregon will be in the dry slot of this system, so precipitation will generally be confined to the west central ID mountains and mountains in Baker County OR, with snow levels around 5000-6000 feet Sunday morning. Conditions dry out by Sunday afternoon as the system quickly moves east, with windy and dry conditions following the front. A Red Flag Warning has been issued for very dry and windy conditions Sunday afternoon in the Magic Valley. Dew points reach the single digits on Sunday afternoon across much of the area, with low relative humidities. Winds calm after sunset Sunday as the system quickly moves east. Monday is a transition day before the next frontal system arrives late Monday night. Increasing clouds and showers developing in eastern Oregon late Monday afternoon, moving into southwest Idaho by late evening. Temperatures will be around 10 degrees below normal Sunday before moderating to near normal on Monday.

LONG TERM /Tuesday through Saturday/

Issued 240 PM MDT SAT JUN 6 2026 The upper-level trough that began moving through at the end of the short term period will continue to move east Tuesday and Wednesday. A well-defined cold front will move eastward across our zones during this time, supported by the deep upper low moving across WA and Northern ID. The low will move across northern ID Tuesday night and into MT Wednesday. This track will continue cool, showery, and frequently windy weather in our CWA, with snow levels lowering to near 6000 ft early Wednesday. Total QPF through Thursday is 0.25 to 0.75 inches in Idaho north of the Snake Basin, and in eastern Baker County/OR. Elsewhere, QPF is 0.05 to 0.25 inches, including the Snake Basin in ID. The least amount of precipitation (around 0.05 inch) is expected in central and northern Malheur County/OR. Snow may accumulate near an inch in eastern Valley County and northern Boise and Elmore Counties above 6000 feet. As the upper low exits Wednesday, continued northwesterly flow aloft will persist, maintaining the cool wx into Thursday, at least on the Idaho side. On Friday, our CWA will begin a warming and drying trend that will last through at least next weekend.

AVIATION /06Z Sunday through Monday/

Issued 1143 PM MDT SAT JUN 6 2026 VFR. Mid-level clouds with ceilings 8-10kft MSL over e-central Oregon and w-central Idaho through Sunday morning. Surface winds: W-NW 10-20 kt with gusts to 30 kt through 12Z Sunday, remaining elevated in the Snake Plain east of KBOI after 12Z. Winds aloft at 10kft: W 15-25 kt, becoming NW after 18Z Sunday.

KBOI...VFR. Surface winds NW through Sunday, gusting to 25 kt overnight, then settling to less than 15 kt after 16Z Sunday morning.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Red Flag Warning from Sunday afternoon through Sunday evening for IDZ424-426. OR...None.