Reading material: Pattern favorable for snow
* Weekend snow chance: Accumulation Potential | Full Forecast *

Model simulation of flow pattern for the weekend, conducive to snow. In particular, the red shading over Greenland illustrates a big "block" in the flow -- which should help keep cold air in place. Source: NOAA.
Almost two years ago, soon after we launched this blog, CWG contributor Matt Ross wrote a piece "Where's all the snow?" that discussed why it hadn't snowed much that winter and the necessary ingredients for significant snow here. It's worth a read now, because the ingredients he talked about *could* come together this weekend.
Over on the EasternUS Weather Forums yesterday afternoon, retired NOAA meteorologist Wes Junker posted an excellent narrative along with illustrations detailing the stunning similarity of the pattern forecast to evolve this weekend (shown to the right) with patterns that have supported big snows in the past. Note, however, despite highlighting the favorable pattern, Junker cautioned "the storm could slip east ... [meaning] accumulating snow for dc but not a real biggie."
I recommend reading Matt's piece first, then Junker's, and feel free to follow-up with questions (Junker's post, in particular, is on the technical side)...
By
Jason Samenow
| December 17, 2009; 1:15 PM ET
Categories:
Winter Storms
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Previous: A look back at last week's historic weather
Next: Major snowstorm increasingly likely
Posted by: Ian-CapitalWeatherGang | December 17, 2009 1:38 PM | Report abuse
Is it just me or is anyone else having a problem with the links?
Posted by: bhfairfax | December 17, 2009 1:45 PM | Report abuse
It is not just you.
Apparently guests to the forums are being frozen out, and there is no way to register either. Its a shame as there is usually great stuff on there on a run-up to a possible big snow storm.
Posted by: GISman | December 17, 2009 1:50 PM | Report abuse
snow!!! so exciting :)
Posted by: madisondc | December 17, 2009 1:52 PM | Report abuse
oh, okay. hopefully they'll open it back up soon. thanks.
Posted by: bhfairfax | December 17, 2009 1:56 PM | Report abuse
Ooooh! The little red border just showed up on my weather.com browser toolbar! Winter Storm Watch in effect. I'm ready for a big, big snow.
Issued by The National Weather Service
Baltimore/Washington, MD
1:48 pm EST, Thu., Dec. 17, 2009
... WINTER STORM WATCH IN EFFECT FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY NIGHT...
THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A WINTER STORM WATCH... IN EFFECT FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY NIGHT.
* PRECIP TYPE... SNOW.
* ACCUMULATIONS... HEAVY SNOW WITH ACCUMULATIONS GREATER THAN 5 INCHES.
* TIMING... SNOW WILL BEGIN LATE FRIDAY NIGHT AND WILL CONTINUE THROUGH SUNDAY MORNING.
* TEMPERATURES... UPPER 20S TO LOWER 30S THROUGH THE EVENT.
* WINDS... 10 TO 20 MPH THROUGH THE EVENT... WITH GUSTS OF 25 TO 30 MPH SATURDAY AND SUNDAY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT SNOW THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST FORECASTS.
Bring it!!!
Posted by: someonelikeyou | December 17, 2009 1:56 PM | Report abuse
@GISman and bhfairfax
That's unfortunate. Recommend registering...
Posted by: CapitalWeatherGang | December 17, 2009 1:56 PM | Report abuse
The EasternUS forum has been having some server issues, and with this snow forecast, they are just getting hammered and I suspect guests are being blocked. It is a great site, so go back at a quieter time and register.
Posted by: JohnDunlop | December 17, 2009 2:05 PM | Report abuse
Great read, Jason. Chilling parallels.
Is the latest watch posted by NWS realistic? Reason: gusty winds with cold and snow... I refrain from the B word, but is this a reality or wishful thinking?
Also, what resource to you recommend on how to best measure snowfall totals so I may report in this weekend with realistic numbers?
Posted by: dprats21 | December 17, 2009 2:26 PM | Report abuse
As indicated in my CWG post earlier today I mentioned that many of the storms here have their roots in the downstream influence of weather systems originating the Asian continent that subsequently interact with storms over the Pacific and sources of tropical moisture. That looks to be the case for the expected east coast storm this weekend.
Posted by: SteveT-CapitalWeatherGang | December 17, 2009 2:36 PM | Report abuse
The Eastern U.S. weather board routinely blocks me as a "guest" whenever there's a run-up to a major snowstorm, severe weather event or tropical event.
Registering can sometimes be an issue, as you have to have another password & login information to remember. The main advantage is that you can download attachments you are barred from as a guest. you can also post to the forums.
Posted by: Bombo47jea | December 17, 2009 11:19 PM | Report abuse
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Some more good reading material:
Historic Lower Mid-Atlantic Snowstorm Increasingly Likely