Which air mass may produce an occasional nor'Easter in the winter?

The air mass that may produce an occasional nor'easter in the winter is the maritime polar (mP) air mass. This air mass originates over the North Atlantic Ocean and brings moist, cool air. When it interacts with cold air from the continental polar (cP) air mass moving southward, it can lead to the development of significant winter storms known as nor'easters, characterized by heavy snowfall and strong winds.