Cold Air Damming (CAD) also know as a wedge. This feature builds in at the surface when a high pressure in the Mid-Atlantic or Northeast exceeds the strength of 1030mb, usually occurring throughout most of Western Virginia, Western North Carolina, some of Upstate South Carolina, and Northeast Georgia. The feature is relatively dominant when a system moves in, when it is built in.

Types of CAD

There are three types of CAD:

Classical- Classic cold air damming generally involves a strong 1030+mb surface high pressure in the northeastern US funneling cold air southward east of the Appalachian mountains. The surface high is locked into place by confluence over the northeast and the continued feed

In- Situ- During In-situ damming a surface high pressure has deposited a cold dry air mass but the parent high has shifted out to sea and is no longer funneling a continued feed of arctic air into the damming region. The air mass becomes locked into place as warmer air is forced up and over the cold dome and precipitation is generated.



CAD often is what results in ice storms throughout the CAD region. In addition, CAD also is a buffer to severe weather events when present,negating the threat down to a minimal level.

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