Interesting. In Bastardi's 500 mb northern hemisphere forecast on the 18th, he predicted much of this cold weather, and the reasons why regarding warm water near Alaska and the resulting ridge that is allowing such cold weather to come over the top, so to speak.
One of the things I like about him is he tries to find historical precedence in wx scenarios. He stated that he found a similar polar outbreak of this magnitude in...1918. The date of your picture reminded me. If anyone's interested, the analysis from 1/18 is still posted at his site:
http://www.weatherbell.com/