* WHAT...Heavy snow expected. Total snow accumulations between 10 and 18 inches. * WHERE...A portion of central Pennsylvania. * WHEN...From 10 PM Saturday to 1 PM EST Monday. * IMPACTS...Travel could be very difficult to impossible. Widespread and prolonged travel disruptions are expected. * ADDITIONAL DETAILS...Snow will overspread the area late Saturday evening into Saturday night, becoming heavy at times through Sunday with accumulation rates of one to two inches per hour at times. Snow may mix with sleet or freezing rain near and south of the Pennsylvania Turnpike on Sunday afternoon, which may cut down on total snow accumulations. Frigid temperatures and wind chills are expected before, during, and after the winter storm. Some blowing and drifting snow is possible.