Monday, December 20, 2010

Widespread White Christmas Expected Across US

For the second consecutive winter, a cold and stormy December has set the stage for a white Christmas across a significant part of the U.S. While snow cover is not likely to be quite as extensive as it was last year, a late-week storm might cover the ground in a magical white in parts of the East by the end of Christmas Day.

The depth of the current snow cover will guarantee a white Christmas in the Rockies and interior parts of the West, as well as in the northern Plains, much of the Ohio Valley, the Great Lakes and interior parts of the Northeast.

Snow cover is spotty or completely lacking in parts of the mid-Atlantic region and coastal Northeast, but meteorologists are watching a late-week storm that could change that. Computer models are projecting a storm to move from the central Plains on early Friday to along the New England coast by later on Saturday, spreading snow along its path.

If this storm track materializes, fresh snow would be dumped from Iowa to parts of the Virginias, with a brand-new snow cover a possibility for the major cities along the Eastern Seaboard, from Washington, D.C., to Boston.

Early-week storms moving through the West will increase the snow cover in the mountains of the West and Desert Southwest, expanding snow cover into some regions that are bare.

Even with the additional snow this week, snow cover was a little more extensive last Christmas when the combination of Arctic cold and a southern storm produced an abundance of snow.

Snow cover on Dec. 25, 2009, extended farther to the south in the Southwest and Plains than it will this year, with snow on the ground as far south as Dallas. Snow cover was also deep in the Virginias, Maryland, Delaware and southern New Jersey, following the first of a couple of monster snowstorms in what turned out to be the snowiest winter on record.

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Typically, a white Christmas is a virtual certainty in the high mountains of the West, the extreme northern Plains and interior parts of northern New England, with a likelihood of greater than 90 percent. The likelihood drops to just 5 to 10 percent along a line extending from the Texas Panhandle to southern Virginia.

This year, a white Christmas is likely in much of the region, where there is just a 26 to 40 percent chance on average.

A white Christmas is generally defined as having an inch or more of snow on the ground.

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