* cAa (Continental Arctic) air mass: This air mass originates over the Arctic region and is characterized by extremely cold, dry, and stable conditions. It brings the most severe cold waves, often accompanied by snow and strong winds.
* cP (Continental Polar) air mass: Originating over Canada and the northern United States, this air mass is also cold and dry but less extreme than cAa. It can still bring significant drops in temperature, especially when pushed southward by strong winds.
These air masses typically move southward from Canada and the northern United States, pushing warmer air ahead of them. The jet stream plays a crucial role in steering these air masses, and a southward dip in the jet stream can bring Arctic air masses into the central eastern United States, resulting in severe cold waves.
Other Factors:
* Lake-effect snow: When cold air masses move over large bodies of water like the Great Lakes, they can pick up moisture and produce heavy snowfalls, further intensifying cold conditions.
* Wind chill: Strong winds can significantly increase the perceived coldness, making the actual temperature feel much colder.
Note: While the cAa and cP air masses are the primary drivers of cold waves in the central eastern United States, other air masses like maritime polar (mP) can also contribute to cooler temperatures, especially when they mix with cP air.
