Polygon Areas News Today

>> reporter: david, good morning. it has been so active. weved had a roller coaster ride in temperatures. take a rook at this arctic front. these four polygon areas are snow squall warnings. national weather service put these into effect a couple years ago, and theyre doing their job. its like a thunderstorm. comes through with a punch, drops a tremendous amount of snow in a short period of time. the visibility gets reduced to below an eighth of a mile, and it could be a whiteout and very treach...