The East Coast of the United States can be very stormy in the winter. Stormsthat form here can become very powerful because of the large temperaturedifferences that often exist. The air over the Gulf Stream is quite mild, whilethe air over the continent can be very cold. This creates a huge weightimbalance in the atmosphere, which is what drives the circulation of theintensifying coastal storm.Often there will be an energy transfer from a storm moving up west of theAppalachians to a secondary system along the East Coast. This is basically whatis going to happen Friday and Saturday. One storm center will come intoTennessee and Kentucky, then there will be a new, more significant developmentalong the Carolina coastline. The coastal storm is the one that is going to domost of the dirty work.

Story by AccuWeather.com Senior Meteorologist John Kocet.