With millions of people preparing to travel for the Thanksgiving holiday, two strong storm systems are forecast to bring high winds, heavy rain and snowfall to a large swath of the United States this week.

Besides a storm brewing over the Great Lakes, a "bomb cyclone" is also forming off the Northwest, promising widespread snow.

A powerful storm is bearing down on the West Coast and bringing with it a scary-sounding weather term - bomb cyclone. Bomb cyclone is a term used by weather enthusiasts to describe a process that meteorologists usually call bombogenesis.