How the potent polar vortex brings Arctic’s frigid weather, winter storms to mainland USA

Meteorologists are calling it among the biggest, longest-lasting chills they’ve seen since monitoring began in the 1950s.

from http://www.firstpost.com/tech/science/how-the-potent-polar-vortex-brings-arctics-frigid-weather-winter-storms-to-mainland-usa-9314111.html