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NOAA details the chances for a white Christmas for the United States

Thursday, December 17th, 2015 8:05am MDT
White Christmas probability map for the contiguous United States. (NOAA)

White Christmas probability map for the contiguous United States. Click for larger view. (NOAA)

With our most recent snowstorm, the Colorado Front Range is likely to enjoy a white Christmas (defined as 1 inch of snow on the ground on Christmas Day).  Other locations in the United States of course are not quite so lucky and historically, Colorado can be quite hit or miss.

Below is the latest narrative from NOAA.  To the right is a probability map – click it to view full size.

From NOAA:

Minnesota. Maine. Upstate New York. The Allegheny Mountains of Pennsylvania and West Virginia. Practically anywhere in Idaho. And of course, the Rockies or the Sierra Nevada Mountains. These are the places where weather history suggests you want to be if you’re looking for the best chance of a white Christmas.

The map at right shows the historic probability of there being at least 1-inch of snow on the ground in the Lower 48 states on December 25 based on the latest (1981-2010) U.S. Climate Normals from NOAA’s National Climatic Data Center.  Dark gray shows places where the probability is less than 10 percent, while white shows probabilities greater than 90  percent.

The 1981–2010 Climate Normals are the latest three-decade averages of several climatological measurements. This dataset contains daily and monthly Normals of temperature, precipitation, snowfall, heating and cooling degree days, frost/freeze dates, and growing degree days calculated from observations at approximately 9,800 stations operated by NOAA’s National Weather Service.

While the map shows the climatological probability that a snow depth of at least one inch will be observed on December 25, the actual conditions this year may vary widely from these probabilities because the weather patterns present will determine the snow on the ground or snowfall on Christmas day. These probabilities are useful as a guide only to show where snow on the ground is more likely.  For prediction of your actual weather on Christmas Day, check out your local forecast at Weather.gov.

You can locate Normals data for the observing station closest to you using the NCDC’sinteractive map.

If you would like to keep track of the snowfall across the United States on a daily basis, see the National Operational Hydrologic Remote Sensing Center’s National Snow Analyses. For a more detailed assessment of the probability of a white Christmas as well as documentation of the methodology used to calculate the map’s underlying climatological statistics, see the scientific paper, White Christmas? An Application of NOAA’s 1981-2010 Daily Normals, by NCEI scientists and published in the Bulletin of the American Meteorological Society. You can also download a spreadsheet to see the full list of stations and their historic probabilities.

This post was adapted from an article first published by the National Climatic Data Center. It was first published on December 11, 2013, and is reviewed each year and updated as needed.

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