Tens of millions of Americans will find themselves recalibrating – and in some cases canceling – holiday plans over the next week, as an exceptionally intense Arctic front plows across most of the eastern two-thirds of the United States during the run-up to Christmas Day.

Below-freezing air will push to the Gulf Coast by Christmas weekend, with readings likely to dip below zero Fahrenheit from Oklahoma to Ohio late this week. On top of this, a "bomb" cyclone (one that deepens by at least 24 millibars in 24 hours) will race from the Central Plains to the Great Lakes on Friday and Saturday, December 23-24. Fierce winds and heavy snow are expected to produce widespread blizzard conditions and shut down transportation over portions of the Great Lakes and Midwest on one of the year's busiest travel weekends.