Polar vortex could unleash winter wallop by January

Winter got off to a fast start in the Lower 48 even before it was technically winter. Waves of cold gripped the eastern two-thirds of the U.S. and several winter storms tracked across the region.

Conditions have since eased some but the heart of winter lies ahead. Will cold and snowy conditions return and turn more harsh?

http://www.startribune.com/polar-vortex-could-unleash-winter-wallop-by-january/503076111/