textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Gusty winds this afternoon in south-central Idaho, including the Western Magic Valley and Camas Prairie. - An atmospheric river will continue valley rain and heavy wet mountain snow in Baker County/OR and the Central ID Mountains through Saturday night.

- Very strong wind Saturday along and behind a cold front. - Record high temperatures expected next Tuesday through Thursday. Monthly record highs for March will also be threatened.

DISCUSSION

Issued 943 AM MDT THU MAR 12 2026 Forecast remains unchanged for today and tomorrow, but have made some updates this morning to the Saturday forecast and products.

The latest forecast update shows much lower winds for Saturday in the West Central/Boise Mountains and the Lower Treasure Valley. The greatest threat of strong winds in these zones will generally be isolated to ridgetops, except in any strong showers or thunderstorms that form along the cold frontal passage on Saturday morning. These gusts look to max out at 40-50 mph with any convection that does form, although current forecast confidence is low. Therefore, have opted to cancel the high wind watch for those zones this morning. Strong winds with gusts up to 55 mph will likely form along the cold front for southeast Oregon, the Upper Treasure Valley, the Magic Valley and along the NV border, with the high wind watch still in effect for those zones.

SHORT TERM /Through Saturday Night/

Issued 328 AM MDT THU MAR 12 2026 Forecast is essentially unchanged through Friday night with a Wind Advisory remaining in effect in south-central Idaho this afternoon and early evening. That area, which includes the Western Magic Valley and Camas Prairie, will have sustained west winds 25 to 35 mph with gusts to 50 mph. Meanwhile, moderate to heavy pcpn will continue in the northern-most part of our CWA, i.e., along and north of 45N. Snow level, near 5000 feet MSL this morning, will rise to 6000-6500 feet this afternoon and stay there through Friday night. Today will be about 8 to 10 degrees warmer than yesterday, then remain mild through Saturday morning.

Saturday is looking increasingly likely to bring an impactful wind event into our CWA as a very strong speed max aloft, currently in the Gulf of Alaska within already strong zonal flow aloft, comes inland and through our CWA. The pattern has similarities to the wind event of December 17, 2025. We issued a High Wind Watch for all zones Saturday afternoon and early evening. West or northwest gusts up to 60 mph are possible along and just behind a surface cold front that will move eastward across our zones. The front itself, as well as the upper level feature, look stronger than before, with reasonable consistency among latest models. The front now has greater thermal contrast across it and should bring colder air into our CWA Saturday night than forecast earlier, with snow level lowering to valley floors by Sunday morning as pcpn comes to an end.

LONG TERM /Sunday through Thursday/

Issued 328 AM MDT THU MAR 12 2026 Sunday looks sunny, breezy, and colder under strong northwesterly flow aloft. The cooling will be brief, however, as an upper ridge in the eastern Pacific will shift rapidly inland and begin a strong warming trend Monday. Tuesday through Thursday look very warm with record high temperatures likely, generally in the mid 70s to lower 80s in the valleys and 60s to lower 70s in the mountains, which would make them among the highest temperatures ever experienced so early in the year.

AVIATION /18Z Thursday through Friday/

Issued 1145 AM MDT THU MAR 12 2026

Generally VFR under mid to high clouds. However, areas of MVFR/IFR and obscuration in the central Idaho mountains and NE Oregon in low clouds and areas of rain and snow. Snow level 6-7kft MSL. Areas of low-level wind shear tonight as surface winds decrease. Surface winds: SW-NW 10-20 kt with gusts 20-30 kt, except 30-40 kt on ridgelines and in the Magic Valley. Winds aloft at 10kft MSL: W 45-55 kt.

KBOI...VFR under mid to high clouds. Low-level wind shear tonight. Surface winds: NW 10-15 kt with gusts to 25 kt through the afternoon, decreasing to 5-10 kt this evening, then ENE 5-10 kt after Fri/09Z.

Weekend Outlook...Light rain and snow will continue across the northern mountains on Friday. On Saturday, a cold front will bring heavier rain and snow to the central Idaho mountains, especially in the morning, with light precipitation elsewhere. Very windy on Saturday along and behind the front. Precipitation decreasing Saturday night, drier on Sunday. Areas of MVFR/IFR and mountain obscuration in precipitation, otherwise VFR. Snow level lowering to 4-6kft MSL Saturday behind the front. Surface winds: W-NW 10-20 kt with gusts to 30 kt Friday, NW 20-30 kt with gusts to 45 kt Saturday, NW 5-15 kt Sunday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...High Wind Watch from Saturday afternoon through Saturday evening for IDZ014>016-028>030. Wind Advisory until 7 PM MDT this evening for IDZ016-028-030. OR...High Wind Watch from Saturday afternoon through Saturday evening for ORZ061>063.