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Posted at 11:00 AM ET, 12/14/2010

Recap: Lake enhanced snow streamers dust D.C.

By Jason Samenow

Snow whips in the wind in Cleveland Park last night around midnight. By CWG photographer Ian Livingston

Mother nature keeps finding new ways to make it snow in 2010. Last night, parts of the District and Montgomery county received a dusting to about half an inch of snow from snow showers which originated over Lake Erie.

The snow arrived in a thin, narrow band oriented northwest to southeast between 11:00 p.m. and midnight. About 60 miles long but no more than 10 or so miles wide, areas to the band's west and east were left flakeless. But in the sweet spot, the fluffy snow briefly came down hard, wildly swept around by 20-25 mph winds. Every powdery flake stuck with air temperatures around 20 degrees.

Usually, lake effect or lake enhanced snow showers dry up before they reach the metro region as their moisture gets squeezed out by the mountains to our northwest. But last night, the impressively strong flow from the northwest coupled with plenty of lift in the atmosphere from upper level energy allowed some of the snow streamers to hang together.

Keep reading for more imagery and reports...

Top left: infrared satellite image from midnight. Top right: regional radar image from midnight. Bottom: local radar image from 11:42 p.m.

The satellite and radar imagery above from around midnight last night show the streams of snow originating over Lake Erie, with the bottom image a close-up of the culprit band stretching over the middle of the metro region. To the northwest in western Pennsylvania and eastern Ohio, the snow bands were more intense. Several inches have already fallen there with up to eight inches in the forecast.

Lake effect snow forms when cold air flows over the relatively warm waters of the Great Lakes. Here are a couple good links about lake effect snow:

* USA Today basic explanation
* Technical tutorial from University of Wyoming

While flurries and snow showers came as a surprise to many, they were mentioned in the forecast overnight released at 3:30 p.m. It would not have been possible to pinpoint exactly where such a narrow band of snow would set up or the timing.

Here are some snow reports from CWG readers and Twitter followers:

@ishgebibble: quarter of an inch in Damascus area
@seoulfully: maybe 1/4" accumulation in Silver Spring (4 Corners ish)
@ebuie: About 1/4" in Wheaton
@debiguity: nothing at all in arlington or anywhere along my commute to lorton/newington.
@PlantDrEMB: Ashton, Md ¾" dry powder
@Georgetowner: a healthy accumulation in Georgetown. Half inch maybe?

Snow outside the Cleveland Park metro station last night. By CWG photographer Ian Livingston

Reader photos:

@katieblaze: Photo from Florida and R (near Dupont Circle)
@ClarendonPatch: Snow in Court House at 1 a.m.
@InVinoVeritasBC: Snow in D.C. (I think this in the West End)

By Jason Samenow  | December 14, 2010; 11:00 AM ET
Categories:  Latest, Recaps, Winter Storms  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Forecast: Woeful wind through Wednesday
Next: Double trouble? Tracking two snow threats


Just fyi, the latest run of the GFS looks good for snowlovers!

Posted by: snowedin85 | December 14, 2010 11:22 AM | Report abuse

I think it might be about time to dust off the Snow Lover's Crystal Ball.

But back to the topic at hand, last night's snow streamers were really cool.

Posted by: Jason-CapitalWeatherGang | December 14, 2010 11:26 AM | Report abuse

Jason, thanks for answering my question last evening regarding the lake effect snow, with an article no less. My biggest concern is now concerning some of the snow I consumed, and fears of death's imminence given the snow's source. I'm afraid I'm more flammable than I was yesterday because of Lake Erie's tributary, the Cuyahoga River. Is this a meterologist's concern or one for the Doc?

Posted by: bloodynose | December 14, 2010 11:37 AM | Report abuse

Is this the same storm the models have been flip-flopping on for some time now? If so, how many consistent runs are generally needed before this becomes a serious threat?

Posted by: ThinkSpring | December 14, 2010 11:39 AM | Report abuse

The latest GFS has the area in the 10+ inch range. However, the models have been flip flopping like crazy on this storm, so don't get your hopes up snowlovers... yet. :)

Posted by: JTF- | December 14, 2010 11:56 AM | Report abuse

In the winter, I always read your name as "Jason Samesnow."

Posted by: megamuphen | December 14, 2010 12:11 PM | Report abuse

in ian's cleveland park picture, that looks like enough snow to scoop up a snow ball! so that was lake effect snow from lake erie!? unbelievable, to me. do we know how often that happens? cool how it's in such a straight line.

think spring,
apparently it's the "euro" model that's not cooperating.

how much of that dry snow is lost to transpiration?

Posted by: walter-in-fallschurch | December 14, 2010 12:21 PM | Report abuse

Ah, the Euro is the outlier for now.

Thanks for the info, Walter.

Posted by: ThinkSpring | December 14, 2010 12:29 PM | Report abuse

That's hilarious, megamuphen! So do I! Great minds! :)

Posted by: Rcmorgan | December 14, 2010 12:33 PM | Report abuse

Jason, This fast (yet thorough) recap is excellent and just the sort of thing that makes the CWG an impressive site.

Posted by: hawknt | December 14, 2010 12:41 PM | Report abuse

The best lake-enhanced/lake-effect snow around here seems to be a direct north-south fetch off Lake Ontario--it's a rather rare setup for us, but the snow squalls don't have as much mountainous terrain to cross before reaching Washington. They do have more land area to pass over before reaching us though.

Even rarer for us would be a northeasterly fetch producing oceanic or Bay-effect snow squalls. Oceanic enhancement occasionally makes midwinter nor'easters particularly momentous around here--provided there's a deep enough subfreezing layer in place directly overhead. Otherwise it's just a wintry mix, a frozen-to-rain setup, or a slug of boringly chilly wind-driven rain. Too often the northeasterly wind shifts to southeasterly, ruining the "party" for us.

Posted by: Bombo47jea | December 14, 2010 1:04 PM | Report abuse


A good bit of the dry snow is lost to transpiration when there is so little. When I went to bed at 1 a.m. (in NW DC), we had a solid coating (prob 1/4-1/2 an inch) everywhere. When I got up, it was quite patchy despite temps in the low 20s.



Posted by: Jason-CapitalWeatherGang | December 14, 2010 1:13 PM | Report abuse

I love this kind of snow. I used to get it a lot when I lived in upstate NY. It would often look like a blizzard when it fell but it would only last a few minutes. And it would be so dry that it blew around like dust...and then it was gone. It is a very different kind of snow.

Posted by: blablabla | December 14, 2010 1:31 PM | Report abuse

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