* WHAT...Heavy snow expected. Total snow accumulations between 9 and 12 inches. * WHERE...Crawford, Northern Erie, and Southern Erie Counties. * WHEN...From 7 PM this evening to 1 PM EST Monday. * IMPACTS...Travel will be very difficult at times due to slippery road conditions and poor visibility. The hazardous conditions will impact the Monday morning commute. * ADDITIONAL DETAILS...Snow will spread into the region late tonight and peak in intensity during the day Sunday. The snow will gradually taper off Monday. Sub-zero wind chills are expected tonight into Sunday morning, and again Sunday night into Monday morning.