Monday, December 23, 2013

I'm Dreaming of a Dry Christmas

Most people in South Carolina usually dream of a white Christmas.  There have been so few times that it has happened in this area.  In fact Climate Central did the calculations and the chances are less that 1% of seeing a white Christmas in Columbia.  Where is the best place to be?  See the map below:

The chance of seeing a white Christmas across the U.S.  Click on the image for a larger version.  Image Credit: Climate Central.

Even though the map shows the historical odds of a white Christmas, the actual amount of snow in a given location can vary a lot from year to year due to natural weather variations.  For example, this year, U.S. snow cover in mid-December was the largest it’s been in a decade.  Outside the U.S., it’s worth noting that Siberia, generally one of the coldest places on Earth for this time of year, had a scorching November with temperatures up to 14°F higher than normal.  That warm trend has continued into December, leaving a "snow shortage".  We can identify with a snow shortage.

The graphic below shows the warmest, coldest, wettest, and the whitest Christmas on record for Columbia.  A Climate Central analysis found that winter is the fastest-warming season in the U.S. over the last 100 years.  That's in step with the global increase in temperatures caused primarily by heat-trapping greenhouse gases.  While climate change is causing winters to warm overall, temperatures on a single day such as Christmas (or any other day of the year) can show large variability—coming in much colder, or much warmer, in a given year than the overall trend would suggest.  Christmas will definitely feel like winter this year.

The extremes of Christmas Day in Columbia, SC.  Click on the image for a larger version.  Image Credit: Climate Central.

So why am I dreaming of a dry Christmas?

It turns out the rain has fallen for the past eight Christmas Days (see table below).  Think of it, if you have a child less than nine years of age, they have never seen a dry Christmas Day.  What a bummer!  Santa brings certain toys, but you can’t go out a play with them.  How about the tradition of playing some sport with friends after the Christmas meal (if your big meal is midday), which has not been a good idea of late.

Christmas Day Rainfall

Interestingly it has rained 48 times on Christmas Day in the past 125 years of records. This year Mother Nature is sending us a hard freeze for Christmas morning.  However, it will be a dry cold; the first dry Christmas since 2004.  Enjoy!