This will be one of those classic cold air damming situations in which cold airis backed up against the Appalachians and just sits there, while mild, moistair attacks from the southwest. Being much lighter, mild air rises up and overthe low-level cold air to create the perfect setup for ice.Because the warm layer exists, it can't snow, but sleet or freezing rain dooccur. The worst case is when rain falls all the way to the ground in liquidform, then freezes to a glaze of ice on everything. That's when travel becomesthe most hazardous, and the extra weight of the ice can bring down treebranches and power lines.
The ice storm will begin in western North Carolina and southwestern VirginiaThursday night, then spread northward to interior Pennsylvania and upstate NewYork Christmas Day. Approximate starting times of the ice event are shown here.
We also show the region where we feel the icing will be most pronounced.
Story By AccuWeather.com Senior Meteorologist John Kocet.
