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Posted at 03:41 PM ET, 12/13/2012

White Christmas tracker, December 13


European model simulates storm forms well off the East Coast in the middle of next week (StormVistaWxModels.com)
Today we must downgrade chances of a White Christmas in Washington, D.C. area as the potential for a combination of cold air and storminess appears somewhat less promising than previous days.

Yesterday, the models appeared to be converging on a major storm during the middle of next week which *might* produce a little snow at the tail end. (Temperatures were very marginal for supporting snow). Even in that scenario, the prospects of enough snow to last into Christmas were slim. But today, most model guidance takes the storm out to sea, with no precipitation.

Beyond next week’s non-storm, we still favor a cold pattern (although some guidance suggests normal to above normal temperatures) which could support snow. However, this cold pattern may also be dry. Notably absent in long range simulations (granted, these could still change) is an active southern jet stream which would pump moisture into the region.

From the look of things, the prospects of a big snowstorm before Christmas seem very low, but I can’t entirely rule out a “clipper”-like system from the northwest that could produce some lighter snows leading into the holiday.

The latest long-range snow cover output from the CFS and GFS models add to the pessismistic outlook.

The GFS model - for the fourth consecutive day - shows no snow on the ground Christmas day.


The GFS model simulates no snow in the Washington, D.C. metro region as of 7 p.m. Christmas Day. (WeatherBell.com)

The CFS model - for the first time this week - shows no snow in any of its four simulations over the D.C. area. in the 5 days leading up to Christmas.


The CFS model forecasts for maximum snow depth from December 20 to December 25 indicate bare ground for the D.C. area. (WeatherBell.com)

Taking all of this information together, I’m decreasing the odds of a White Christmas in D.C. from 15 percent yesterday to 10 percent today. A 10 percent chance of a White Christmas matches the low historical odds.

Related: How often does Washington, D.C. have a White Christmas?

Standard disclaimer: these forecasts more than a week into the future are very unreliable. They have not demonstrated the ability to accurately predict the weather this far out in time.

We’re showing you the models so we can see how they evolve (i.e. do they shift snowier, less snowy, or constantly flip flop?) and then, in hindsight, evaluate how well or poorly they simulated reality.

Previous White Christmas Trackers:

December 10, 2012
December 11, 2012

December 12, 2012

By  |  03:41 PM ET, 12/13/2012

Categories:  Latest, Holidays

 
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