Weather whiplash: Late-fall warmth ends as coldest air of the season invades more than 30 states

Weather whiplash: Late-fall warmth ends as coldest air of the season invades more than 30 states

The coldest air of the season is plunging as far south as Florida this weekend, bringing below-average temperatures to more than 280 million people after what has been the warmest fall on record for many places across the eastern and central U.S.