woman in fur hoodie*(Via NBC News) – The worst of the brutally cold “polar vortex” that plunged millions of Americans into a deep freeze was over Wednesday, forecasters said, but temperatures remained between 10 and 20 degrees lower than normal.

The weather system was receding north, having set new record low temperatures in 50 cities on Tuesday.

Minneapolis-St. Paul, Minn., spent 62 consecutive hours below zero. Chicago spent 37 hours below that threshold, including 29 hours in double digits below zero, according to The Weather Channel.

Subzero temperatures were still widespread across the upper eastern half of the United States on Wednesday, but most areas affected by the extreme cold were beginning to thaw. Conditions are expected to be back to normal by Friday.

Temperatures plummeted as a whirlpool of frigid, dense air known as a “polar vortex” descended on much of the United States.

“It’s still going to be below average for most of the East but the worst of the Arctic outbreak is over with,” said Guy Walton, a meteorologist at The Weather Channel.

Get the FULL story at NBC News.

Visit NBCNews.com for breaking news, world news, and news about the economy