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Posted at 6:30 AM ET, 12/16/2010

Snow update: Timeline, Impacts, and FAQs

By Jason Samenow

(originally posted 9:30 p.m. Wed. night, updated 6:30 a.m. Thurs. morning)

With only one or two inches likely (less north of town, maybe up to 3" south of town), Thursday's storm is far from a blockbuster. But the light, powdery snow predicted to fall may cause some minor disruptions. The National Weather Service has extended a winter weather advisory northward through the entire metro region today (from 10 a.m. to 9 p.m.).

Use the information below to help you prepare for this minor event...


7 AM to 11 AM
Light snow develops southwest to northeast. Temps 20-25.
11 AM to 3 PM
Light snow, moderate snow south. Temps 25-30.
3 PM to 7 PM
Snow tapers to flurries west to east. Temps 22-27.



Where is the storm now?

Follow the progress of the storm on national radar and regional radar.

How confident are you in your forecast?

We are confident that will at least be a little snow. Computer model guidance has been pretty consistent in simulating a light snow event for the region. There will be a sharp northern cutoff to the precipitation not far from the metro region which adds a little complexity to the forecast but at least there's no question about precipitation type - sure to be all snow due to the cold temps.

What are the chances of lower or higher amounts of snow than forecast?

There's about a 1 in 3 chance snowfall is above or below the 1-2" (or 1-3" in southern suburbs, 1" in northern suburbs) we've forecast for the metro region. So we think there's a 15-20% chance we get less than inch (or close to nothing in the northern suburbs), and 15-20% we got more than 2" (or more than 3" in the southern suburbs).

Where and when will conditions be the worst?

Most likely in late morning through mid-to-late afternoon before the snow quickly pulls away. Though the snow may end toward the beginning of the evening rush hour, it's likely to be a difficult one due to earlier snow particularly on untreated roads, bridges, ramps and overpasses.

Will the snow stick? will mostly stick due to very cold weather of late.

How will travel be impacted?

Untreated roads may well become slick when snow is falling. The snow will not be particularly heavy so crews should be able to keep up with the snow on major roads. Airports may experience some minor delays but widespread cancellations or airport closures are not anticipated.

How will schools be impacted?

Most schools are likely to open on time with the snow not moving in until around mid-morning. However, some schools to the south of the District have decided to close in anticipation of the snow. Some schools may decide to close early. It's not out of the question that a few schools delay opening Friday morning, but road crews will have plenty of time to clear roads before then.

What are other outlets forecasting?

* Topper Shutt (WUSA-TV9): Around 1"
* Bob Ryan (WJLA/TBD): Around 1"
* Doug Kammerer (NBC4): 1-2"
* National Weather Service: 1-2"
* Sue Palka (Fox 5): 1-3"

By Jason Samenow  | December 16, 2010; 6:30 AM ET
Categories:  Latest, Winter Storms  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: PM Update: Still cold, waiting on snow
Next: Forecast: Snow likely today, unlikely Sunday


First time commenting here but have been following CWG for sometime now. Love the detailed forecast CWG has been giving, including which part of the day is likely to have the worst conditions, forecasts for north of DC (where I am) and south of DC, and evaluating likely impact for travel, etc. Very useful info for people who have to travel in the snow. Very few other online sources that I know of have this kind of useful details. Great job, guys!

Posted by: creativekev | December 15, 2010 9:51 PM | Report abuse

I like the addition of the predictions of other local forecasters. Hope you keep a running tally for the season of over/under predictions.

Posted by: ah___ | December 15, 2010 9:53 PM | Report abuse


Thanks for the nice comment. We appreciate the feedback.

Posted by: Jason-CapitalWeatherGang | December 15, 2010 9:57 PM | Report abuse

0z NAM is painting a more intersting picture for this area tomorrow...looks like it trended north a bit.

Posted by: swishjobs | December 15, 2010 10:11 PM | Report abuse

CWG - very nice write-up. I too like the addition of the other forecasts.

Walter in FC - how much snow do you typically need to create something? My guess is that 1-2 does not cut it but possibilities start to appear once you get to 3? How much does the fact that a snow may be dry impact your abilities?

Posted by: amaranthpa | December 15, 2010 10:14 PM | Report abuse

Hi swishjobs - I probably don't need to tell you that that is just one solution of one model, and we would need to watch a trend develop (evolve or devolve) between model runs. One point on a graph doesn't draw a trend line necessarily ;)

Posted by: Camden-CapitalWeatherGang | December 15, 2010 10:19 PM | Report abuse

I want to chime in and agree with creativekev that you guys are much more useful than any other forecasts I've seen. You give the kinds of details I need to know, especially stuff like how sure you are. That makes it much easier to make plans!

I discovered this blog last winter and I rarely bother to check anyplace else now!

Posted by: marag | December 15, 2010 10:21 PM | Report abuse

Thanks for the level of detail, especially with the maps and timelines. Honestly, you guys are becoming my go to source for weather information. I too want to encourage the comparison among the various local forecasters. Not to see who is right, but to see the variation among the local forecasters,nearly all of whom have been here a rather long time. Thanks.

Posted by: madennis | December 15, 2010 10:53 PM | Report abuse

Indeed, CWG is the final word for snow around here. I don't pay attention to anyone else aside from checking to see if there's any disagreement with the CWG forecast. Discovered them during last blessed winter and have been here ever since. Weather without the hype.

Posted by: AdmiralX | December 15, 2010 11:00 PM | Report abuse

This could be puppy's first good snow. I'm sort of looking forward to it... sort of.

Posted by: waterfrontproperty | December 15, 2010 11:06 PM | Report abuse

so the OOZ gfs is now even further OTS. I know we are looking for a pattern here before we put a nail in this coffin, but the EURO and GFS are looking pretty much the same with this OTS soultion for the weekends storm.

Probably time to look ahead to next tues-wed time frame, according to the 00Z, looks like something is lurking our way in the middle of the country!?!

Posted by: KRUZ | December 15, 2010 11:29 PM | Report abuse

unlikely that schools will let the kids go early since it's difficult to round up all the drivers and get them back to the schools without several hours advance notice (I drive a bus...) but afternoon and evening activities may be canceled - easy to do and costs nothing.

Posted by: plantlady1 | December 16, 2010 12:05 AM | Report abuse

Agree with marag, madennis, and AdmiralX. Like marag, I switched to checking my weather at CWG and don't bother checking anywhere else now.

Posted by: creativekev | December 16, 2010 1:02 AM | Report abuse

6+ for much of the area tomorrow but more south

Posted by: cpm2cv | December 16, 2010 1:07 AM | Report abuse

One of the only times snow simutanius here, Raleigh NC and Boulder Co... all Family spots! This blog is just the only blog I look at, in the age of Facebook. who knows what will be the rage of 2015?

Posted by: pvogel88 | December 16, 2010 2:52 AM | Report abuse

i need 2-3". the fact that this might be "light and fluffy" snow is bad actually as 3" of fluffy snow is really much less when compacted. this will be a close one. i'll start harvesting as soon as the snow stops, but can't make anything until the temps are ABOVE 32 so the snow becomes "packing snow".

i got spoiled last winter...

Posted by: walter-in-fallschurch | December 16, 2010 6:49 AM | Report abuse

I have missed hearing from you Walter. I look forward to seeing your sculptures, weather permitting of course !

Posted by: winterishere | December 16, 2010 7:56 AM | Report abuse

A fine, light snow has been falling in Charlottesville since about 8 am. Careful driving, people: this stuff is sticking fast to all the roads.

Posted by: shmoozer | December 16, 2010 8:58 AM | Report abuse

Disappointed about no Sunday storm, but it leaves things clear for the big Saturday night dance at Glen Echo.

I'm experiencing problems logging into American Weather Forums issue??? The rest of my access seems OK though Comcast seemed to have a few problems around 2 PM yesterday.

Snowing here pretty good ATT--please see my post above.

Posted by: Bombo47jea | December 16, 2010 10:38 AM | Report abuse

The comments to this entry are closed.

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