Model predictions for the intensity of the cold snap range from historic and record-breaking to rather run-of-the-mill for midwinter.
Yeah, these guys are great. The cause is the polar vortex attacking us. This is air at 60,000 feet, near vacuum, coming down to thick soup air, and freezing us. The notorious jet stream is also involved.
As I have said, these villains are ghosts, having no energy themselves, yet they plot nice.
If, for some reason, you believe that only energetic objects can hit us, then there is a another explanation: no heat in the N. Hemi. That just makes us all generally cold and sometimes, super cold.
Following energy, as a good physics person would, we find that there is a hot, warm 'super plume' hitting our cold mass of air. That jiggles it out of place and we find ourselves at 50 below.
If we break records, then we have more confirmation we are in an ice age. If we still want to go with global warming, we can say that carbon is bringing down the polar vortex and jet stream upon us. Fantasy is a big seller.
ps. I'm thinking of ice cream in a bucket. It sits there until the scoop comes along...