FXUS65 KBOI 211215 AFDBOI Area Forecast Discussion National Weather Service Boise ID 615 AM MDT Sat Mar 21 2026 .UPDATE...Updated aviation discussion. && .KEY MESSAGES... - A cold frontal passage Saturday will bring cooler temperatures, light mountain showers, and gusty W-NW winds through the evening. - Warm, slightly above normal temperatures will continue the middle of next week. - Another cold front will move through the region by the middle of next week, bringing mountain showers and cooler temperatures. && .SHORT TERM /Through Monday Night/... Issued 334 AM MDT SAT MAR 21 2026 Visible satellite and radar imagery shows the cold front moving into central Oregon, with high clouds filling in over our region this morning as of 3AM MDT. Temperatures are very warm, with Twin Falls sitting at 60F. This expansive ridge of high pressure will degrade over our region today, thanks to the cold frontal passage. This cold front will elevate winds across the region this afternoon, especially in the Upper Treasure-Magic Valley and near the Nevada border with gusts up to 35 mph. Chances of precipitation have decreased as the bulk of the moisture stays to our north, with northern portions of Baker County-Valley County seeing a 10-20% chance of light rain showers. Snow levels will stay above 8000 feet MSL, with only high summits seeing snowflakes with this frontal passage. Temperatures will remain warm and above normal, but about 10-20 degrees cooler than yesterday. Overnight lows tomorrow morning will be especially different, with lows reaching near or below freezing across the region. The ridge will then begin to build back in over our area on Sunday, keeping the cool zonal flow more to our north than has been previously modeled. This will keep temperatures above normal on Sunday and Monday, with dry conditions. && .LONG TERM /Tuesday through Saturday/... Issued 334 AM MDT SAT MAR 21 2026 An atmospheric river extending from a low off the British Columbia coast will bring moisture to the Pacific Northwest on Tuesday. This will try to push colder air and precipitation into our region, but it will compete with the persistent ridge of high pressure over the Desert Southwest. Models continue to have disagreement in the progression of the AR compared to the ridge development, however most ensemble solutions keep warmer temperatures over the region and light precipitation over Baker County and higher terrain in southwest Idaho through Thursday. Accumulations look to be light with snow levels staying above 7000-8000 feet. Forecast highs have fluctuated significantly on Wednesday and Thursday, with better agreement in warm and dry conditions for the weekend thanks to a rebuilding ridge. A few outlier solutions show a low bringing cooler temperatures and mountain precipitation again by Saturday. Forecast confidence is high that our area will see unseasonable warmth continue with at least slightly above normal temperatures through the long term period. && .AVIATION /12Z Saturday through Sunday/... Issued 611 AM MDT SAT MAR 21 2026 Generally VFR. A cold front will move NW-SE after Sat/14Z, bringing isolated rain showers near KBKE/KMYL. Low chance of MVFR conditions in showers. Mountains obscured near KBKE-KMYL in low clouds. Surface winds: variable up to 10 kt until Sat/18Z, then W-NW 5-15 kt with gusts to 15-25 kt, except gusts up to 30 kt in Magic Valley. Winds aloft at 10 kft MSL: W-SW 20-40 kt. KBOI...VFR. Surface winds: SE or variable less than 10 kt. Becoming W-NW 8-15 kt after Sat/16Z with cold front. Afternoon gusts around 18-25 kt. Weekend Outlook...Becoming VFR tonight into Sunday. Surface winds: NW or variable 5-15 kt. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. &&$$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise AVIATION.....SA SHORT TERM...SA LONG TERM....SA