textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- A strong cold front will bring gusty winds, isolated thunderstorms, and mountain showers tomorrow. The strongest winds are expected in the Lower Snake Plain, south of Boise.

- Temperatures will dip below freezing tomorrow night, with much cooler daytime highs on Sunday.

- An early season heat wave will lead to record high temperatures area-wide Tuesday through Thursday.

SHORT TERM /Through Sunday Night/

Issued 222 PM MDT FRI MAR 13 2026 Breezy and cloudy conditions will continue through the evening for most of the region. Light precipitation in far northern Valley and Baker County is anticipated through the evening, with minor accumulations. A strong cold front is anticipated to move through the region tomorrow, bringing much cooler temperatures, gusty winds, isolated thunderstorms, and a brief period of valley rain and mountain snow. The front looks to move through northeast Oregon and the West Central Mountains early Saturday morning, hitting the Snake River Valley by the late morning. Embedded heavier showers and thunder are possible (<10% chance) along the front, with the better chance (20% chance) of a stray thunderstorm behind the front in the afternoon over southwest Idaho. Thunderstorms could produce outflow wind gusts up to 50-60 mph.

Gusty winds will be the primary concern with this event, with sustained northwest to westerly winds around 30-40 mph and gusts from 50 to 60 mph on ridgetops and in the Upper Treasure Valley south of Mountain Home, Camas Prairie, and Magic Valley. The winds will not be as strong in the Boise area, with sustained westerly winds anticipated to be around 25-35 mph with gusts up to 50 mph. Winds will be slightly lower but still strong elsewhere, especially in valleys that can channel westerly winds. Crosswinds along north-south oriented roadways will make travel for high profile vehicles dangerous. Blowing dust is also a concern, primarily near fallow fields in the Magic Valley. This could temporarily reduce visibility to less than one mile along the US93 and I-84 corridors.

After this frontal passage on Saturday, cool and mostly dry conditions with light winds will return for Sunday. Lingering light showers will continue for the mountains, with snow levels reaching valley floors on Sunday morning. Temperatures Saturday night will dip down below freezing for all of the area, a nearly 25 degree difference from the overnight lows on Thursday and Friday.

LONG TERM /Monday through Friday/

Issued 222 PM MDT FRI MAR 13 2026 A strong and persistent upper level ridge remains the dominant feature across the Intermountain West through Friday, bringing an early heat wave to the region. Warming begins in earnest early in the period, with Monday temperatures propped up 15 degrees warmer than Sunday, reaching approximately 5 to 10 degrees above seasonal normals. By Tuesday, temperatures rise further to about 20 degrees above normal, threatening daily high temperature records for St. Patrick's Day.

From Wednesday through Friday, temperatures hold steady at 20 to 25 degrees above normal, with Thursday currently looking like the warmest day of the stretch with temps forecast around 80 degrees for many valley locations. Each day from Tuesday through Friday will not only threaten daily records but will also challenge the warmest maximum temperatures ever recorded for the month of March. We may even see our earliest 80 degree day in Boise. For historical context, the warmest day in March for Boise, Idaho, was 82 degrees set on March 26th 1877, and the earliest 80 degree day was March 19th 1997. Winds remain mild, and skies will stay partly cloudy. Afternoon relative humidity values are expected to range from 20 to 30% in the lowlands and 30 to 50% in the mountains.

AVIATION /00Z Saturday through Sunday/

Issued 531 PM MDT FRI MAR 13 2026

VFR overnight under mid-high ceilings. Precipitation increasing, especially in the central ID mountains, Sat/AM with a cold front. LLWS ahead of the front. Localized MVFR conditions in Precip w/ mtn obscuration. Front exiting our area mid-day Saturday with scattered showers through Sat/PM. Isolated lightning Saturday. Snow levels: 6.5-7.5 kft MSL this evening, lowering to valley floors behind the front. Surface winds: Variable up to 10 kt overnight. Then W-NW 15-30 kt with gusts to 25-45 kt late Sat/AM through Sat/PM, strongest near KTWF/KJER. Winds aloft at 10kft MSL: W 30-50 kt.

KBOI...VFR. Winds light and variable overnight, then W-NW 15-25 kt with gusts up to 35 kt late Sat/AM through Sat/PM behind a cold front. LLWS Sat/AM ahead of the front. Rain showers with periods of MVFR conditions late Sat/AM along the front. A 15% chance of lightning from Sat/15-23z.

Weekend Outlook...Precipitation decreases Saturday evening. Areas of MVFR/IFR and mountain obscuration in precipitation. Snow levels lowering to 4-6kft MSL Saturday behind the front. Surface winds: W-NW 5-15 kt Sunday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...High Wind Warning from noon to 9 PM MDT Saturday for IDZ014- 016-028-030. Wind Advisory from noon to 9 PM MDT Saturday for IDZ015-029. OR...Wind Advisory from noon MDT /11 AM PDT/ to 9 PM MDT /8 PM PDT/ Saturday for ORZ061>063.