...MAJOR WINTER STORM WILL IMPACT THE REGION THIS EVENING THROUGH SUNDAY EVENING... .A large area of precipitation will overrun Arctic air in place over the Mid-Atlantic. This will lead to widespread significant snow beginning this evening, with the potential for ice Sunday especially south of Highway 50 and near and east of Interstate 95. In addition to the high threat for significant snow and ice, very cold temperatures are expected tonight through the middle of next week with sub-zero wind chills likely at times. * WHAT...Heavy mixed precipitation expected. Total snow and sleet accumulations between 5 and 10 inches and ice accumulations around one quarter of an inch. * WHERE...Portions of southern Maryland and central and northern Virginia. * WHEN...From 11 PM this evening to 4 AM EST Monday. * IMPACTS...Power outages and tree damage are likely due to the ice. Travel could be nearly impossible. * ADDITIONAL DETAILS...Snow will likely overspread the area tonight, becoming heavy at times with rates of one to two inches per hour possible at times. A mix with sleet or freezing rain is expected Sunday. Visibility of one-quarter mile or less is possible at times. A prolonged period of very cold wind chills continues this evening and lasting through the middle of next week.