The US is preparing for one of its coldest Christmases on record with temperatures on Christmas Day expected to fall to under –20 degrees centigrade in some states. Even on the East Coast, where it has been till now been unseasonably warm this winter, below zero temperatures are expected to accompany Saint Nicholas’s arrival.

The above image from NOAA’s supercomputer weather model shows temperatures on Christmas morning. The coloured lines represent a temperature gradient with blue and purple indicating particularly cold weather.
The links below show temperatures on the East Coast of the US at six hourly intervals through the day.
Morning
http://www.scoop.co.nz/stories/images/Christmas.weather/christmas2.gif
Afternoon
http://www.scoop.co.nz/stories/images/Christmas.weather/christmas3.gif
Evening
http://www.scoop.co.nz/stories/images/Christmas.weather/christmas4.gif
The weather patterns the US is experiencing this Christmas were correctly anticipated by the NOAA weather model 12 days ago and published on Scoop. However the intensity of the weather event was not expected at that stage.
See…
http://www.scoop.co.nz/stories/images/Christmas.weather/NYChristtemp.gif
For the earlier weather map
..and...
Scoop Images: Christmas Weather Around The World
For Scoop's earlier story.