Who Will Have a White Christmas?

Probabilities for a white Christmas based on data from 1981-2010 using stations with at least 25 years or more of snow data. White Christmas is defined in this map as 1 inch or more of snow depth on Christmas Day. CREDIT: NCDC/NOAA View full size image

For most Americans dreaming of a white Christmas, Mother Nature will be serving up a lump of coal.

Don't expect much from the storm that wrecked travel in New Mexico and Kansas. It is moving east but it is weakening, so it will likely bring rain and thunderstorms from the Gulf of Mexico to the East Coast this week. A new storm forming over the Pacific Ocean could swing through the Northeast, from Washington, D.C. to Boston, by Christmas Day. But will a "Snowpocalypse" strike for the third straight year? Henry Margusity, a senior meteorologist at AccuWeather.com, isn't betting on it.

"Nah, not going to happen," Margusity told OurAmazingPlanet.

Margusity said there is no "blocking pattern" in place right now off the East Coast, so temperatures will not drop enough to turn rain into snow.

Blocking patterns there are created by natural changes in atmospheric pressure and wind direction over the ocean, called the North Atlantic Oscillation. Last year, the NAO was in a strong negative phase, which set the tone for a wild winter. This year the NAO is positive. Snow can fall when the NAO is positive – but major snow is not likely.

Last year, a blocking pattern resulted in the Christmas Blizzard of 2010 (loosely named, since it hit on Dec. 26).

The snow cover on Dec. 25, 2010.
CREDIT: NOHRSC/NOAA

View full size image

Blizzard leftovers

Out west, leftover snow from the big blizzard could mean a white Christmas for parts of New Mexico, Texas and Kansas. Flagstaff, Ariz., where 4 inches (10 cm) of snow is average for Christmas Day, has 9 inches (23 cm) of snow on the ground today.

"I don't think it's all going to melt by Christmas Day," said Ken Daniel, a meteorologist with the National Weather Service in Flagstaff. There's even a "decent shot" at fresh snow there, Daniel said.

Snow flurries are enough to satisfy some people. Others scoff at less than an inch. Both definitions are used variously to describe a white Christmas. [Images: Snowy Landscapes]

The National Climatic Data Center have calculated the probability of having at least 1 inch (2.5 centimeters) of snow on the ground on any given year. Not surprisingly, much of the upper Midwest, Northwest, Rocky Mountains and New England has the greatest probability, at greater than 90 percent. States in the Deep South have a less than 5 percent chance of a white Christmas.

No snow for UK

Today snow covers 23 percent of the country, which is much less cover than last year. On Christmas Day 2010, snow covered 50 percent of the United States.

For Christmas Eve, the NWS's Hydrometeorological Prediction Center forecasts at least 1 inch of snow will accumulate in the far Northwest, the tippy-top of the Great Lakes, western New York and New England. The forecast does not yet include Christmas.

In the United Kingdom, last year included a white Christmas. Snow has fallen on Christmas Day in the U.K. 38 times in the last 51 years, according to that nation's weather service, the MET Office. Brits shouldn't expect another one this Dec. 25, though.

"This year's probability of seeing a white Christmas across most of the U.K. is pretty much zero," said Helen Chivers of the MET Office.

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You can follow OurAmazingPlanet staff writer Brett Israel on Twitter: @btisrael. Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet and on Facebook.