Helping to support an eastward expansion of the Western U.S. cold is a shift to positive phase of the global atmospheric angular momentum. During +GLAAM regimes, the mid-latitude jet stream strengthens and the hemispheric pattern becomes less amplified.

A massive Northern U.S. storm stretches from the Northwest Coast to New York State by early this afternoon. Featured is heavy snow with high wind leading to blizzard conditions at times across the Dakotas to Minnesota and the northern Great Lakes where 1-2 feet of snow is possible and snow drifts cause greater than several foot pileups. Just south of the heavy snow, a band of freezing rain accreting to >0.5 in. is expected.