1. Polar Vortex: The current extreme cold spell in New England is primarily attributed to a southward displacement of the polar vortex. The polar vortex is a large-scale atmospheric circulation pattern characterized by low pressure and cold air concentrated near the Earth's poles. When the polar vortex expands and dips southward, it can bring frigid temperatures to regions that would typically experience milder winters.

2. Jet Stream: The jet stream, a powerful atmospheric current, plays a significant role in shaping weather patterns. During winter, the jet stream typically flows from west to east across the United States, helping to moderate temperatures. However, when the jet stream becomes distorted or buckles, it can allow cold air from the Arctic to penetrate farther southward, leading to severe cold spells like the one experienced in New England.

3. Snow Cover: Extensive snow cover in the region acts as a positive feedback loop, amplifying the cold weather conditions. Snow reflects sunlight, preventing the ground from absorbing solar energy and warming the air. This further contributes to the persistence and intensification of the cold temperatures.

4. Radiational Cooling: During clear nights, the Earth's surface loses heat through radiation, causing temperatures to drop. In the absence of cloud cover, which traps heat and acts as an insulating layer, the loss of heat radiational cooling can be more pronounced, leading to extremely low overnight temperatures.

5. Wind Chill: Strong winds can exacerbate the feeling of cold by increasing the rate of heat transfer from the body. Wind chill refers to the combined effect of temperature and wind speed, which can make it feel colder than the actual air temperature.

It's important to note that the combination of these factors can create a "perfect storm" for extreme cold weather, resulting in the dangerously low temperatures currently being experienced in New England.