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Posted at 11:23 AM ET, 11/02/2011

Do October and November snow signal a snowy winter?


Years with snowfall during October in Washington, D.C. in left column, October snow amount in center column, seasonal total in right column. (Matt Rogers)
OK, so we had some snow in parts of our area last month (just a trace at Reagan National and .6 of an inch at Dulles), now that it’s November, we could have some more. Time will tell. (I don’t do the forecasting on this blog.)

But what does October snow mean, if anything, for the rest of the winter as a whole? And what about November? I decided to do some of my own research.

Let’s begin by reviewing all the years during which snow has fallen in October at Reagan National Airport (and its predecessor locations beginning in the late 1800s). The table to the right ranks the “snowiest” Octobers top to bottom and then lists how much snow fell the entire season.

I don’t see a big correlation here, but winters during which it snowed in October average 4.4” more than the recent thirty year ”normal.”

[Note: Whereas the 30 year average snowfall is 14.5” in D.C., the all-time (1888-2011) average snowfall is 18.2” - pretty similar to the average snow in years when it has snowed in October as reported by Capital Climate.]

Not even some of the brutally cold winters of the past, such as those of 1917-18 and 1933-34, had any snow in October. And there was no October snow during D.C.’s two snowiest winters on record: 1888-89 and 2009-2010. However, since official D.C. snowfall records don’t go back far enough, it’s unclear whether there was any October snow during some of the frigid winters of the 1870s and 1880s.

Earlier, the Rev. C.B. Mackee, known for his painstaking work in recording D.C.’s Civil War weather, observed little, if any, October snow from 1860 to 1864. According to Mackee, except for a few occasions, even Novembers were relatively snowless during the war.

To take this a step further, the following charts give a picture of snowfall during past winters when measurable snow (more than a trace) occurred in either the previous October, November, or both.

For the sake of clarity, the record is divided into 3 separate periods, each including 13 or 14 winters.




Total snowfall (in blue) during years when there has been measurable snow in either October or November.

As you can see, of the span of more than 120+ winters, only about one-third of them had snow in either October or November (none had measurable snow in both months).

The exceptionally snowy 1898-1899 (54.4”) had 4.8” of snow in November and quite a few of the snowy winters during the late 1800s and early 1900s experienced measurable snow during that month.

During the mild winters with merely average snow in 1938-39 and 1953-54, there were, respectively, 7.0 and 6.7 inches of snow in November - making up a substantial fraction of those season’s snowfall.

In years with measurable snow during November, the average seasonal snowfall climbs to 23”.

So whereas Snowtober probably means little with respect to the upcoming season’s snowfall, a snowy November might be more of a harbinger of higher than normal snowfall.

In a related article to this one, AccuWeather presented opposing viewpoints on the issue of fall snow as a predictor of winter:

Sensing that we’ve established a pattern that will reassert itself all winter, AccuWeather senior meteorologist Joe Lundburg said: “When you see a weather pattern start to develop in the fall, [the patterns] tend to repeat themselves throughout the winter.”

But at the same time, Brett Anderson, another Accuweather meteorologist, asserts that “there’s no real correlation between big October snowstorms in the East and rough winters.”

So, in answer to the title question, “What does the winter have in store, snow-wise?”—I suppose no one really knows for sure. But stay tuned: The Capital Weather Gang is about to make its assessment. Nevertheless, whatever that assessment is, for the real snow-lovers out there, you can always interpret our October snow as a harbinger of things to come. For the rest, just think of it was just as an aberration.

(Matt Rogers, Ian Livingston, and Jason Samenow contributed to this post)

Related reading:

Does October Snow Signal A Wild Winter Ahead? (Our Amazing Planet)
Does an October Snowstorm Mean a Bad Winter’s on the Way? (AccuWeather)
Early Mid-Atlantic Snow: Seasonal Harbinger or Freak Event? (Capital Climate)

By  |  11:23 AM ET, 11/02/2011

Categories:  Latest, Winter Storms, Local Climate, Lipman

 
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