Nearly the entire U.S. is going to have a colder than normal Christmas week: NOAA

The U.S. weather pattern during Christmas week is going to be what forecasters call "highly amplified." This means that the jet stream, which separates air masses and steers weather systems, will be undulating sharply — with large northward bulges, or high pressure ridges, and deep dips, or low pressure troughs, toward the South. 
For Christmas week, this jet stream configuration will allow Alaskans to enjoy an unusually mild holiday, while residents of virtually the entire lower