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December 17, 2009

Weekend snowstorm now looks likely

The National Weather Service forecasters out in Sterling have finally come around, raising the snow chances for Central Maryland to 80 percent for Saturday. They're still uncertain how much moisture, and therefore how much snow, the storm will produce here. But, apparently, snow it will. Winter weather advisories, or watches, could begin to appear in the forecast this afternoon.

UPDATE 5 p.m.: The National Weather Service has posted a Winter Storm Watch for all of Maryland, from late Friday night until late Saturday night. At least 5 inches of snow is expected, with more possible. is calling for 8 to 12 inches from Washington to Dover, Del. The earlier post resumes below.

Snow fans and school kids should check out Mr. Foot's forecast. He's talking about 8 to 12 inches, with some impact on school schedules on Monday.

As we've said, there will be plenty of cold air in place. There's a low-pressure system parked over AccuWeather.comNova Scotia, and the counter-clockwise rotation around that low is pulling a steady stream of cold air around the western side and pumping it into the Northeast. That will make it cold enough for this storm to be all snow here, with a rain/snow line - this time- well to our south and east.

The real snow-maker will be the low that is cranking up over the Gulf of Mexico. It will track east, providing another drenching for the Deep South. Then it will emerge off the southeast Atlantic coast early Saturday and begin to head north and east.

Circulation around that low will begin to pump Gulf and Atlantic moisture our way. The main snow band on the maps (that's one possible scenario, above) runs from western North Carolina, straight up the I-95 corridor to Boston. Here's another from AccuWeather's Henry Margusity, showing that he believes 3 to 6 inches could fall here.

The snow is likely to start falling here in the wee hours of Saturday morning, if the forecast holds up. Highs on Saturday will hover near freezing, so we should see some snow all day, continuing into early Sunday morning.

It's supposed to stay cold early next week, and there is some chatter about a Christmas storm. Could we have a rare Baltimore white Christmas? Stay tuned.

Posted by Frank Roylance at 7:17 AM | | Comments (29)
Categories: Winter weather


No, please say it aint't so!! I have a dinner party planned for Saturday night. Help, Frank, please use your weather wizardry to stop this storm in its tracks -- or at least hold off until Sunday!

oohhh, why can't it snow during the week????

Hey Frank! Can you fill-in the 2004- present data from your '05 review of Baltimore's White Christmas probabilities?

FR: Sure. Here is the dismal record of recent Christmases in Baltimore:
2008 - HI 59 LOW 32 A TRACE OF RAIN
1998 --> HI 33 LOW 13 SUNNY AND COLD

How am I going to do all my Christmas shopping if it's snowing??? Ahhhh.

FR: Retailers are wondering the same thing. I suspect workplace absenteeism will spike on Friday, and maybe next week, too.

Let it snow, let it snow, let it snow!!!!!


I commented on your post yesterday that the forecasters would start talking about a big snow by this afternoon. I sometimes wish the local TV guys weren't so slavish in following the NWS on their calls. For this storm, Tony Pann and Tom Tasselmeyer from Channel 11 have been out there and done a good job, but the rest just seem to parrot the NWS. So after not talking about snow all week, they'll be hyping it like crazy later today when/if a winter storm warning is posted.

C'mon! My daughter's turning 3 and her party is scheduled for Saturday. We need people to come over and share chocolate cupcakes with pink frosting -- her request! There can't be snow!!!

Darn, too bad it won't snow all day sunday for the game... looks like i'll have to start tailgating at 7:00 so i can dig my spot out and make a natural beer cooler :) thats me going green do i get a tax break :) not in MD

Well, it was only a matter of time before I found how my rear wheel drive 'stang would handle some snow...(No snow when purchased last spring...) And, yeah, Frank, pull some strings please - I've got a lot to do this weekend.

I always welcome news of snow. Hope this doesn't put a snag in my last-minute Christmas shopping plans, though. But let's not panic before the first flake falls.

Still, have to remember to put milk, eggs, bread and T.P. on my shopping list...

NOOOO!! We are moving into our new house on Saturday! There goes the new carpets and wood floors. Someone please say this is a joke.

If there is a decent snow here on Saturday, retailers are going to feel an impact. Studies have shown that the busiest shopping day is not the day after Thanksgiving but the Saturday before Christmas.

I love the snow, the only problem is I would have to drive in it because my wife is in retail has to open her store on Saturday morning.

Thanks for the post to Mr. Foot's forecast. I linked it on my FB page and I had a friend ask if it is for real. I told her it is as real as any other forecast. It all depends on if it is correct. I love making Baltimore people panic.

Let the Baltimore Snow Death Watch begin!

I remember the '02 Christmas storm, my 1st winter in New Freedom, PA, on the state border. We wound up with almost a foot. The winter of 02-03 is when we had the blizzard, we received 36" in New Freedom! Bring on the snow this weekend & let's have a WHITE CHRISTMAS!!!!

The Winter Storm Watch was just posted.

Don't worry, if they are saying a foot or so...that means it will flurry! You guys should be fine with shopping and the dinner parties.

Ditto Glamour Girl. I have a 50th Surprise Party to attend early Saturday evening. NO SNOW until LATE Saturday, then, "LET IT SNOW"

It was a lot more fun to live in the Hereford zone when I was a kid and snow meant the promise of a day off school. I did not have to worry as I do as an adult about things like getting to work, what about heat if the electricity goes out and do we have enough milk? Snow is beautiful but a pain now to deal with. My employer expects me to be at work and doesn't care how much snow there is on the ground.

Bastardi at AccuWeather says 12 inches at BWI and DCA.

I can't believe all the people complaining about not being able to go out in the snow. Learn how to drive. But then again most of you complaining drive like a slug in the rain (you know who you are), drive slowly and travel in the fast lane (not sure if you know who you are, but it's illegal) and are the main reason most peoples' commutes are 2x what they should be. If you are afraid to drive, just stay in. Enjoy the snow with your family.

Just waiting for the first drunk sledding of the year. Look out Key Highway!


Time to stock up on bread, toilet paper, and milk-- the trinity of Baltimore snowstorms.

Frank, any way you can pull up on stats on how often it snows on weekends vs. weekdays for the past winter or couple of winters. Odds say it should snow on school days 5/7 of the time but seems like storm tracks pass through on weekends for the past year.

Is it just my imagination?

FR: I could ask the folks at Sterling to look into it, but they're a tad busy with this storm. Or, you can do it yourself with data on the website. Click here: I'd bet that, with a large enough sample, the storms will fall evenly across the week. The planet doesn't know what day it is.

Oh yes the snow is coming-the question is will it be a relatively tame 5-10" of snow like the GFS forecast model, the Canadian and UKmet models are indicating, or will it be the monster that the WRF forecast model is predicting.

Take a look for yourself at the WRF (a respectable and heavily relied on tool used by all forecasters)-

This is total precip for the storm-that's right 3-4" liquid which at a 10" snow to an inch of liquid would give us--well you can figure it out....

This is where the storm will be this time on Saturday evening according to the WRF-

If the WRF verifies, this would be a snowstorm for the recordbooks. All the forecast models are keeping it below freezing at all layers for BWI, DCA (National Airport ) and IAD (Dulles). So it looks like an all snow event for the western shore except perhaps briefly down around Pt. Lookout.

I think that 8-12" for central MD is not an excessive forecast, in fact if the WRF is right it will be significantly more.

Stay tuned as the trends for all the major models over the past 24 hrs has been towards more snow not less.

Still these coastal storms can be jiggy as the devil and you really can't be sure how things shake out, regardless of model trends, until its over and done with....

FR: Yikes! Those models seem to put us in a very intense bullseye. Guess we're just going to have to wait and see. Thanks for the links.

The 0z (7pm) WRF has come in and it is very similar to this afternoon's run with the bulleye of heaviest precip shifted over the Bay.

I half expected the afternoon run was overdone and would be hard to replicate. A true outlier.

The fact that this evening's model run is in the same range is making me a little nervous because Baltimore/D.C. doesn't handle that much snow very well.

The GFS model will be out shortly. It was the one most of the NWS and Accuweather guys where leaning towards and it was yielding the 6-12" amounts forecast by accuweather.

If the GFS trends further toward what the WRF has shown us today, it could be Katie bar the door...

Models results don't mean it will happen, but that said I haven't seen the models imply something of this magnitude since the Feb 2003 snow that broke the our area's record.

In 45 years living in Maryland, I've never seen the models this pumped for a December storm. The storm of Christmas eve 1966 was the closest analog I can recall.

This storm has the potential to be a very dangerous event. People shouldn't blow this one off.

Lets see IF the weather forcasters * get it right this time. * They ALWAYS predict * lots of snow and we ususlly * DON'T get it. Get your TP and MILK now !! 8^) ****

I'm so angry. I wanted to get some shopping done. Couldn't it have waited until next week? Last Saturday was wonderful weather, 50 and sunny. WTH happened? Eh, it would be funny if nothing but an inch of snow fell!

FR: Or, alternatively, you could have shopped last week. 8-)

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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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