A major winter storm will arrive in northern Utah on Thursday and continue into Saturday, but the good news is that it’s expected to improve air quality.

According to the National Weather Service, a “weakening weather disturbance” will reach the area on Wednesday, with light precipitation in far northern Utah. The storm is not expected to “entirely clear out the urban haze as it passes through.”

PM 2.5 pollution — fine particulates — rose to yellow (or moderate) caution levels in Cache and Weber counties by Wednesday morning, according to the Utah Department of Environmental Quality, and the inversion is expected to worsen there and in other counties. However, a stronger storm will arrive on Thursday afternoon, clearing the air and bringing “significant snowfalls” to the mountains, with the Wasatch range “receiving the bulk of the snow.”

The heaviest snows and coldest temperatures are forecast for Friday night through Saturday as a “series of weather disturbances sweeps south across the state." Snow accumulations of 12-24 inches are possible in the mountains, which could make travel “very difficult to impossible.”

(Courtesy of the National Weather Service) A winter storm is expected to arrive in northern Utah on Thursday.

Northern Utah valleys can expect rain, or rain mixed with snow, through at least early Friday; the precipitation will turn to snow later that day. The best chance for snow accumulation on the valley floors will be Friday night through Saturday.

Forecast highs in the Salt Lake area are in the low 40s on Wednesday, Thursday and Friday, with overnight lows in the mid-30s. Highs in the mid-30s are expected on Saturday and low 30s on Sunday and Monday, and overnight temperatures will dip to the high teens or low 20s.

The precipitation will reach central and southern Utah by late Friday night or early Saturday, but only “minimal” snow accumulation in the mountains is expected. Valleys in southern Utah will see mixed rain and snow.

Dry conditions will return throughout the state on Sunday.