A strong cold front is forming today and will plunge through the Deep South, bringing a 40 deg. F temperature drop.
Here’s a time lapse video of hourly temperature forecasts from the WRF high resolution model, showing just how abrupt the temperature change will be as the front passes (original graphics from Weatherbell.com):
Winter storm warnings have been issued for northern portions of the South where up to a foot of snow is expected, mainly through the Ohio River Valley: