Al Roker explained the term Polar Vortex. It's not a new term. He shared a page from one of his college textbooks where it's explained. The severity of that last cold we had was much colder than what we in Kentucky normally experience, and apparently everywhere else as well. I suppose that's why they were looking for a different term to describe it from what is normally used. These two pages explain it a little better: From the weather channel--->
http://www.weather.com/news/weather-...nuary-20140117 and for a simple definition--->
http://en.wikipedia.org/wiki/Polar_vortex Whatever they use to describe it, we about froze our butts off in Kentucky! lol lol