Time to Dream of a White Christmas (2013)
It is the most popular question of the season for the weatherman; namely, will we have a White Christmas?
While the 100 year trend says the odds are against us (a mere 2 or 3 out of 10 Christmas days manage to be white), the pattern that has set up this year is more favorable than most years so far this century.
By way of review only 2003, 2009 and 2010 have had snow on the ground on Christmas day since the new Millennium began. In fact if you are a purist (like my esteemed colleague Ken Batty from the National Weather Service in Charleston) then you would exclude the 2003 snow since it fell after sunrise.
This year though the early season pattern has already spat 6 snowfalls (or at least dustings) our way. Now less than 2 weeks before Christmas, it appears another slushy coating can grace our presence this next to last weekend before Santa’s trip in from the North Pole.
In fact the snow that fell on Sunday December 8th and was enhanced by a second snow on Tuesday the 10th in parts of the area has a tremendous amount of ice in the snow pack. That is the sleet that fell on Sunday and has been preserved by the week long cold snap.
Ice has a much slower melting factor than pure snow, so it will take several warm days and rains to totally melt what we have out there.
While this snow in itself is not enough to lay claim to a White Christmas even if it were to be uncorrupted until the 25th, I feel confident that the ice content in this snow will preserve at least some of this snow all the way until Christmas week.
And there in is the rub of the forecast; namely, save for an occasional few days of moderation in temperature, the pattern looks chilly and stormy for the next 2 weeks.
Now consider that there is a nice snow pack well established along and north of I-70 from the Mississippi River all the way into Pennsylvania.
Here’s the North American snow pack as of press time, thanks to the folks at WSI.
That’s a much larger coverage area of snow than normal for mid December and to me offers compelling hope that a White Christmas can occur locally.
With a new round of snowfall expected for this weekend for the entire stretch from Cincinnati to Columbus to Pittsburgh, a refrigerator effect of sorts will be enhanced heading into Monday.
The importance of this snow pack can’t be overstated; namely, it is keeping the air along and north of I-70 colder than a bare ground would allow. In effect the snow/ice on the ground is promoting more snow and ice with every storm that comes.
As Dr. Joel Myers taught me at Penn State way back when (1980), snow on the ground breeds more snow by making subsequent storms more likely to produce snow over rain.
Granted a nice warm up with rain is likely late next week when the snow pack will dwindle but the pattern looks to revert going into Christmas week with more southern storms meeting cold air from the north.
Where that meeting of the air masses occurs will go a long way to determining what areas have a White Christmas.
So if you long for an old fashioned White Christmas, there is more hope this year than others.
Fingers crossed not just Chicago and Detroit will have snow on the ground come Christmas morning!