Cold air damming leads to a dreary Memorial Day in the Carolinas

DURHAM, N.C. (WTVD) -- It's been unseasonably cool this Memorial Day along with some rain that has made it less than ideal for outdoor plans. The reason for this dreary pattern: Cold Air Damming (CAD).

Cold air damming is a phenomena we experience several handfuls of times a year. This phenomena refers to a cold air mass getting trapped topographically. This has generated stubborn cloud-cover and rain.

High pressure in the northeast today is causing cooler air in the lower levels of the atmosphere to bank up against the Appalachian mountains. Miles up in the atmosphere a relatively warmer air mass is overhead. We refer to that warmer air over a cooler air mass as overrunning.

A similar pattern is expected on Tuesday keeping highs nearly 20 degrees below average. As low-pressure approaches from the west, the rain chance will be amplified. Periods of light to moderate rain are expected as a result.