A winter weather advisory for the southern third of Minnesota takes effect at noon Saturday. The Weather Service says four to eight inches of snow are possible — heaviest along I-90 corridor. Three to six inches of snow are expected from the Twin Cities north to St. Cloud, Little Falls, Alexandria and Mora — less across the rest of northern Minnesota. After the snow, the cold moves in, with lows on Tuesday five- to 10-below in the northwest to around 5 above in the southeast.