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.