Cold Air Damming (CAD)
Cold Air Damming or CAD is a term used in reference to a high pressure that moves into the Northeast, and push cold air up against the Appalachian mountains. This surface cold can create forecast woes along the East Coast, and is responsible for the shallow layer of cold air that produces icy conditions. Many times this cold struggles to reach locations in the mountains, while areas just before the mountains remain 5-7 degrees cooler (sometimes even more). In reference to WNC, Cold Air Damming sets up along the Blue Ridge Escarpment and can create icy conditions around Hendersonville, NC when Asheville is too warm for ice. Depending on how strong the high pressure is will determine is Asheville sees icing during Cold Air Damming events. Usually it takes a high pressure of +1030mb to get enough surface cold to Asheville to reach freezing, but only around 1026mb-1028mb for Hendersonville. Watch the placement of the high pressure, and how strong it is as the event approaches to determine where exactly winter weather will set up around WNC.