@CNN: RT @CNNSitRoom: The coldest air in a generation is pouring across the upper Midwest and heading South and East. About a quarter of the US population will face sub-zero temperatures as the week goes on. CNN meteorologist @AllisonChinchar has the details. https://t.co/epWBPirNuU https://t.co/ZVZohxgjrQ

@CNN: RT @CNNSitRoom: The coldest air in a generation is pouring across the upper Midwest and heading South and East. About a quarter of the US population will face sub-zero temperatures as the week goes on. CNN meteorologist @AllisonChinchar has the details. https://t.co/epWBPirNuU https://t.co/ZVZohxgjrQ