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Posted at 01:46 PM ET, 03/29/2011

Late week snow for mid-Atlantic and Northeast?

The hype is building as one of the primary computer models forecasters rely on (the GFS) is advertising the potential for snow, and maybe lots of it, in parts of the mid-Atlantic and New England for the second half of the work week.

A number of forecasters, including some big-name ones, are talking about accumulating snow amounts even in Washington, D.C. Thursday night into April Fools’ Day.

A critical look at the model guidance would indicate to me accumulation potential region is being oversold...at least in the D.C. metro region

Here’s what I think can be said right now:

*There are primarily two chances to see snowflakes the rest of this work week: Wednesday morning and Thursday night as two areas of low pressure approach from the south - with the Thursday/Friday event the stronger of the two.

* The Wednesday morning snow “chance” is minimal because precipitation may not arrive until mid-morning by which time temperatures would probably be warm enough for plain rain. IF the precipitation arrives early enough Wednesday morning (20-30% chance), it could be snow or a mix of rain and snow, especially in the colder suburbs. But any snow would change to rain by late morning, and rain looks to be the predominant precipitation type through the evening. No accumulation is expected except in the mountains where up to 2-4” could fall above 2,000 feet.


The GFS model image above, valid at 11 p.m. Thursday night, shows low pressure developing off Cape Hatteras and moderate to heavy precipitation having accumulated just south of the metro region, headed northeast. Temperatures aloft are cold enough for snow, but the freezing line at the surface is over western Virginia. So snow falling at temperatures from 33-36 degrees over the metro region would have a hard time accumulating under this scenario. (Source: StormVistaWxModels.com)

* The better chance for snow in the metro region is Thursday night, but even then many ingredients would have to come together for accumulating snow. The current GFS forecast model track of the low may allow for a scenario where rain that begins Thursday afternoon gradually transitions to wet snow Thursday night. Indeed, the model rapidly deepens low pressure off the coast, tapping some cold air and wrapping in some impressive precipitation. But even then, temperatures look to be only marginally cold enough to support accumulation (mainly on grassy areas) -with the best chances in the far north and west suburbs (e.g. Leesburg, Frederick) and the mountains. I should add that other models do not show the same caliber storm as the GFS.

So I’m clearly skeptical. What are some of the other voices saying I alluded to earlier?

WeatherBell (formerly AccuWeather) chief forecaster Joe Bastardi sounded off with the following Tweet:

Double shot of winter love dumps snows on the big cities of the NE..large scale 3-6 with local 12 DC to Boston. Wed-Fri NO APRIL FOOLS!less than a minute ago via web

Houston-based forecaster Larry Cosgrove wrote:

12z GFS version shows a significant wind and snow event for Washington DC - Philadelphia PA - New York City NY corridor on April 1!less than a minute ago via web

And even behind-the-scenes forecaster Jonathan Erdman at The Weather Channel is impressed

Can't take 1 model run as "gospel"....but 12Z GFS solution for the Nor'easter Fri. is VERY impressive. http://twitpic.com/4eo6b5less than a minute ago via TweetDeck

I don’t want to be overly dismissive of the storm scenario as the pattern is certainly a cold and stormy one. And wet accumulating snow is certainly a legitimate possibility for elevated areas a good deal west of D.C., Baltimore, and Philadelphia mainly Thursday night. But - while it can’t be entirely ruled out - I am highly skeptical about the potential for substantial accumulating snow along the I-95 corridor from New York City and points south. The way it looks to me, cities in southern New England such as Providence, Boston, and Portland and their western suburbs stand a much better chance of experiencing a significant April Fools’ Day storm.

By  |  01:46 PM ET, 03/29/2011

Categories:  Winter Storms, Latest

 
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