* WHAT...Heavy lake effect snow possible. Total snow accumulations between 3 and 6 inches possible, with accumulations upwards of 7 to 9 inches across across the northern half of the area. Winds could gust as high as 50 mph. * WHERE...McKean and Warren Counties. * WHEN...From Monday morning through Tuesday evening. * IMPACTS...Roads, and especially bridges and overpasses, will likely become slick and hazardous. Travel could be very difficult. The hazardous conditions could impact the Monday morning and evening commutes. Gusty winds could bring down tree branches.