The East Coast of the United States can be very stormy in the winter. Storms that form here can become very powerful because of the large temperature differences that often exist. The air over the Gulf Stream is quite mild, while the air over the continent can be very cold. This creates a huge weight imbalance in the atmosphere, which is what drives the circulation of the intensifying coastal storm.

Often there will be an energy transfer from a storm moving up west of the Appalachians to a secondary system along the East Coast. This is basically what is going to happen Friday and Saturday. One storm center will come into Tennessee and Kentucky, then there will be a new, more significant development along the Carolina coastline. The coastal storm is the one that is going to do most of the dirty work.

Story by AccuWeather.com Senior Meteorologist John Kocet.