The wedge, scientifically known as cold-air damming (CAD) is a meteorological feature that often occurs on the east side of the Appalachian Mountains. It also occurs on the east side of the Colorado Rockies. Cold-air damming happens when cold, dense air banks up against the side of the mountain. The Mountains act as a dam blocking the shallow, dense pool of cold air which keeps the cold air to the east of the Mountain range. There must also be an area of high pressure to the northeast which supplies the cold air.
This phenomenon can result in a very challenging forecasts for meteorologists as a sharp temperature gradient often occurs. Example: It could be 82° in Columbia while in the upper 50s in Charlotte. This meteorological feature can occur any time of the year, but is most common during the fall and winter months in the southeast.
