* WHAT...Heavy lake effect snow. Additional snow accumulations 1 to 2 feet, with localized amounts of up to 4 feet possible across Oswego County. Snowfall rates of 3 to 5 inches per hour possible in the most intense bands. * WHERE...The Eastern Lake Ontario Region. The greatest additional snow amounts will focus across Oswego County. Additional snowfall in Jefferson County will only be across the far southern end of the county, and in Lewis County only in the far southwest corner of the county, with minimal amounts elsewhere. * WHEN...Until 7 AM EST Saturday. The heaviest snowfall will be tonight through Friday. * IMPACTS...Travel will be very difficult to impossible with near zero visibility and deep snow cover on roads. If you must travel, be prepared for severe impacts and the possibility of becoming stranded.