The worst of the deadly "polar vortex" that sent millions of Americans into a deep chill was over Wednesday, forecasters said, and though temperatures were still below normal gradual warming was on the way. Although freezing temperatures remained across the upper eastern half of the U.S. for much of Wednesday, conditions are expected to be back to normal by Friday, NBC News reported. The brutal chill earlier in the week sent all 50 states below 32 degrees at some point Tuesday.
