(CNN) As if one winter storm around the holidays wasn't enough, a new one is taking shape for New Year's Eve, bringing more heavy rain and a renewed flood threat.

It comes on the heels of the deadly storm system that plagued much of the Midwest, South and East over Christmas.

The worst is over as that storm pushes offshore into the Atlantic. But it killed at least six people in the Midwest and South and brought blizzard conditions, a foot of snow, and winds exceeding 55 mph to the Great Plains and Upper Midwest on Thursday. It then ripped across the East with heavy rainfall and winds.

On Friday, more than 50 million people were under the threat of floods, with flood watches and warnings stretching from the Gulf Coast to New Jersey.

Flash flooding affected Southern Mississippi and Alabama, triggering dangerous situations and high-water rescues. Up to a foot of rain fell in less than a day.

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