Fri Dec 13, 2019: A slow-moving frontal system/trough is producing light snow over eastern Minnesota with lingering low clouds and fog across much of the state. A fourth day in a row of fairly stagnant meteorological conditions (temperature inversion, high relative humidity, light winds, recycling of pollution particles, etc.) has allowed for a high end Yellow (moderate) air quality day over much of central and southern Minnesota. The good news is that gusty northwest winds are already developing over the central and eastern Dakotas. These winds will move across the state overnight into Saturday. Colder temperatures will overspread the region; however, much of the fine particle pollutants in the lower atmosphere will be dispersed allowing for Green (good) air quality on Saturday. Visibility will also be improved with the removal of the pollutants ending the days of hazy skies. Arctic high pressure settles in on Sunday and Monday across the Upper Midwest with cold temperatures to continue. Green air quality conditions expected through Tuesday.