BOISE, ID—A weakening inversion in the Treasure Valley will fully dissipate by Friday evening as winds from a strong trough sweep through the area, clearing dense fog. Tonight, a weak upper trough brings a 30-50% chance of snow, though accumulations will be minimal.
By late Friday night, southwest winds will usher in significant moisture, raising snow levels to 4,500–5,500 feet. Rain is expected in the valleys, including Boise, with no freezing rain anticipated west of the city. A cold front late Saturday night will drop snow levels to 3,000–4,000 feet.
Mountain areas, including central Idaho, face 6–12 inches of snow, prompting a Winter Storm Watch through Saturday night. Another Pacific trough could bring valley snow Monday, while drier conditions return midweek.