* WHAT...Heavy snow expected. Total snow accumulations between 12 and 18 inches, with localized amounts up to 22 inches. Northwest winds gusting as high as 35 mph Monday afternoon will cause areas of blowing and drifting snow. * WHERE...Portions of central New York and northeast Pennsylvania. * WHEN...Until 7 PM EST Monday. * IMPACTS...Travel could be very difficult to impossible. The hazardous conditions could impact the Monday morning and evening commutes. * ADDITIONAL DETAILS...Snow will overspread Northeast PA and the New York Southern Tier between 4 AM and 7 AM this morning, moving north to the I-90 corridor by the mid-morning hours. At this time, the heaviest snowfall is forecast to fall across the northern tier of Northeast PA, Catskills and Susquehanna region of NY. However, minor adjustments to storm total snowfall are still possible. Snowfall will likely be very heavy at times this afternoon and evening with hourly rates potentially exceeding 2 inches per hour. The snow tapers down, becoming light to moderate after midnight and into Monday morning. Occasional light snow and blowing snow then continue into Monday afternoon. Temperatures will be very cold throughout this storm, hovering in the upper single digits to teens the entire time, with colder wind chills.