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Posted at 12:00 PM ET, 02/12/2010

Next snow chance just around the corner

By Camden Walker

* Slow melting better than no melting: Full Forecast *

Next Chance of Accumulating Snow: Monday-Monday Night
Probability of Accumulating Snow (1" or more): 70%

It seems Mother Nature may be intent on making life difficult for school administrators. Some school systems have decided to hold classes on President's Day to make up for lost time, yet the chance of accumulating snow sometime Monday and/or Monday night hasn't gone away, though the exact timing is uncertain and overall forecast confidence is low.

The GFS model depicts the upper-level energy associated with Wednesday's heavy snow (top) and with the storm that could potentially bring snow to the area on President's Day (bottom). Courtesy NCEP.

Low pressure riding the polar jet stream will likely pass just to our south on Monday and could transition into yet another coastal storm. Whether we're looking at a sizeable storm, or little to no snow, depends on how far south or north the potential coastal system develops (the farther south, the better chance for more snow), and whether or not the precipitation "skips over" the D.C. area during the transition.

While not as intense, the overall look and track of the upper-level energy associated with the incoming area of low pressure isn't all that different from that of the last storm, and may be enough to squeeze out some significant snow despite the apparent lack of moisture with this system compared to recent ones. So, we do need to watch how things play out over the next couple days.

Here are our latest accumulation probabilities, which are likely to change as we get closer to this potenital storm:

30%: Less than 1"
30%: 1-3"
25%: 3-6"
15%: 6"+

The Snow Lover's Crystal Ball appears when the potential exists for accumulating snow beyond 24 to 36 hours.

Dan Stillman contributed to this post.

By Camden Walker  | February 12, 2010; 12:00 PM ET
Categories:  Snow Lover's Crystal Ball  
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Next: Amazing mid-Atlantic snow statistics



Posted by: Hawaiiexpat | February 12, 2010 6:01 AM | Report abuse

Oooof. This parade of storms is relentless.

There is hope for everyone stranded up here in MoCo. I have seen some new and serious pieces of snow moving equipment passing through town after this last storm. (I live on an emergency route- Fire station up the street) There were tractor-based, lane-wide snowblowers, the like of which I have not seen since going skiing... and one of them ate my mailbox!!! Lol.

Hang in there!

Posted by: dprats21 | February 12, 2010 6:25 AM | Report abuse

Hopefully people will have cleaned up their walks and their portions of their sidewalks so that this snow will just cover up the brown bits and not cripple the city again.

Posted by: Bainbridge | February 12, 2010 6:45 AM | Report abuse


Posted by: FusilliJerry1 | February 12, 2010 6:50 AM | Report abuse

Are you sure it's not April Fools Day? I hope we stay in the "seven year cycle" and next winter stay relatively snow free! LOL

Posted by: soyboy99 | February 12, 2010 7:47 AM | Report abuse

Monday snow forecast 70% chance of an inch or more......
I've got a bad feeling about this.

Posted by: FIREDRAGON47 | February 12, 2010 7:55 AM | Report abuse

I agree @Firedragon. Yesterday it was 45%. Tomorrow, who knows. I'm going to avoid the blog until Sunday - bad for my blood pressure. :-)

Posted by: fairfax_gal | February 12, 2010 8:45 AM | Report abuse

Sigh. :(

I'm moving someplace where there's less Anchorage.

Posted by: ThinkSpring | February 12, 2010 9:15 AM | Report abuse

Jim in NOVA here --

Honest question to CWG. If you were due to fly into IAD Monday night (9pm), returning from a weekend trip, and you needed to be at work on Tuesday - would you can the trip?

Second question - how early would one's trip need to be Monday to get in before the snow?

I realize things are still iffy but I have to make a decision in the next few hours, based on the best information available.

Posted by: jahutch | February 12, 2010 9:58 AM | Report abuse

I like that 15%.

Posted by: ennepe68 | February 12, 2010 10:03 AM | Report abuse


Difficult question because, as you say, the whole thing is very iffy at this point, both in terms of snow amount and timing. Of the storms we've seen recently, this one probably has the best chance to be a bust or have low impact. But, there's nothing to say that this storm won't start to look more impressive on the models as we get into tomorrow and Sunday. So, the only way to guarantee that you'll be in town for work Tues. morning is to stay put. Otherwise, take your chances and hope that this storm doesn't overperform -- something that we're due for but who knows if/when this winter it will happen.

Posted by: CapitalWeatherGang | February 12, 2010 10:16 AM | Report abuse

PS ... the way it looks now, you'd probably have a better chance beating any snow by arriving back Monday morning rather than Monday afternoon.

Posted by: CapitalWeatherGang | February 12, 2010 10:20 AM | Report abuse

I am real excited about Monday. In that pit in your stomach kind of way.

Posted by: johnslau | February 12, 2010 10:37 AM | Report abuse

me too!

funny thing is, any other year we'd (snowlovers, anyway) all be crazy with excitement about a 70% chance of over an inch of snow. remember how 4 or 6 inches used to seem like a LOT of snow.....?

Posted by: walter-in-fallschurch | February 12, 2010 10:42 AM | Report abuse

Any other year, I'd brush off a forecast like this with a casual "whatever" and go about my business. THIS year? I'm thinking we'll be lucky to escape with anything less than 6".

Posted by: ultrapop101 | February 12, 2010 10:48 AM | Report abuse

I might just do the snow dance...

Posted by: manassasmissy | February 12, 2010 10:55 AM | Report abuse

12z GFS keeps with the .25-.5 qpf for the entire region with an area of .5-.75 ominously close..

Posted by: Dylan0513 | February 12, 2010 11:06 AM | Report abuse

Dylan0513 -- Does .25 - .5 qpf translate to about 4" - 8" of snow? I know an inch of rain is equivalent to about a foot of snow, so I'm wondering if that's what those numbers represent. Could you enlighten me?

Posted by: Garret_in_VA | February 12, 2010 11:19 AM | Report abuse


For those of us that are illiterate in 'meteorology speak', but would like to learn, would you please translate into English what you just posted?

Thank you

Posted by: pmknp | February 12, 2010 11:20 AM | Report abuse

or, if I did my math correctly, 4" - 6" of snow. DOH!

Posted by: Garret_in_VA | February 12, 2010 11:20 AM | Report abuse

One of the CWG people said before that about 12:1 ratios are average for our area, so you'd take the qpf number and multiply by 12. But I've heard that this storm might have higher ratios because of colder air so maybe 15:1 ratios?

Posted by: Dylan0513 | February 12, 2010 11:25 AM | Report abuse

All TV forecasters are saying clippers have no moisture usually. Is the thinking that the one on President's day MAY draw a costal low (again). I didn't think clippers worked in that fashion.

Posted by: cgang | February 12, 2010 11:42 AM | Report abuse


Clippers can indeed spawn or transition into stronger coastal systems. And sometimes enough upper-level energy can make up for lack of moisture. This is all discussed in the article above.

Posted by: CapitalWeatherGang | February 12, 2010 12:05 PM | Report abuse

Looking at the storm that is brining snow to the deep south, what is keeping it from coming up the coast?

Posted by: JW211 | February 12, 2010 12:06 PM | Report abuse

@cgang: Well...the last event was a clipper that linked up nicely with the subtropical jet. The diving system aloft transferred it's energy to the coast, and set off a "bomb" of mid level convergence of air, right where what is known as peak "dendritic snow growth". In English, this explains why there were large flakes beating down during the peak of the blizzard (AM), if the video I viewed was accurate.

This next system initially does not fuse with the subtropical jet, which will have been temporarily displaced farther south by the current wave dropping heavy snow through the Deep South.

However, the chart showing a farther south "dive" could be ominous. A clipper that dives into, say, southern KY/northern TN than rotates ENE into southern VA would be able to pick up some northern Gulf "juice", and pull in some Atlantic moisture if the flow in the snow growth region can back to the Southeast (off the Gulf Stream).

For DC, the deep atmosphere will be colder next Monday than that ahead of Wednesday. No icing. CWG's 25% chance for 3-6 is a smart, safe call, but as they mentioned and I agree, 5-10" can't be ruled out on the high end; a farther north track, would cut values down to the 1-3" range.

By Sunday it will be clear which track is sure to look at water vapor satellite loops to see the "bowling ball" that is the clipper, and how far south it is getting.

Posted by: wxdancer | February 12, 2010 12:10 PM | Report abuse

Isn't it funny that this time last year, we were hoping and begging for a clipper to bring us here we sit, weather weary, shoulder sore and mentally drained from a week in the house watching Annie with two kids...

Posted by: authorofpoetry | February 12, 2010 12:12 PM | Report abuse

If clippers travel far enough south, they can generate a coastal storm [Miller type B cyclogenesis] or intensify one that's nearby through a phasing process.

This often happens off the Delmarva/Virginia Beach area. We're currently in a rather vulnerable Miller B situation due largely to low temperatures resulting from our current snowpack and the existing Greenland block. In a normal situation we get nothing or light flurries, or wintry mix. Currently we would tend to get more snow.

Metro derailment near Farragut North on Red Line. 345 people on train. Feds may have jumped the gun by not staying closed all week. Fortunately only one minor injury requiring hospitalization.

Posted by: Bombo47jea | February 12, 2010 12:14 PM | Report abuse


Nice analysis... just a couple minor corrections -- the last system was not a clipper out of Canada. It originated from a system that came ashore on the West Coast. Also, it's not impossible that with the right track we could have to worry about sleet mixing in. For now, though, it does look like what we'll get would be mostly or all snow.

Posted by: CapitalWeatherGang | February 12, 2010 1:00 PM | Report abuse

Snow Lovers: Now that we've achieved a record winter snowfall..How many inches of snow would we need to reach a record (total) snowfall amount for the month of February? (Could even a small Monday snowstorm put us over the top?!) Thanks.

Posted by: Frida7 | February 12, 2010 1:26 PM | Report abuse


I wanted to post a quick note to say THANK YOU for all of the informative coverage over the past several days and always. Keep up the good work!!

Posted by: DianaJeaninArlington | February 12, 2010 1:48 PM | Report abuse

Wow - another storm! Since we haven't had a bust yet - I think we are do for one.
I'd love another dusting (anything less than 6" seems to now qualify as such) but won't get my hopes up.

Posted by: Bainbridge | February 12, 2010 2:43 PM | Report abuse

What are they doing with all this snow? I figured it was just easy to dump it into the Potomac, but my mother pointed out that with the chemicals used on the roads it's illegal.

Posted by: townhousekids | February 12, 2010 2:51 PM | Report abuse

WOOHOO!!!!!!!!!! C'MON MOMMA NATURE, keep bringin' it!! :) I want to see more snow fall out my window!!

Posted by: sigmagrrl | February 12, 2010 3:00 PM | Report abuse

Bainbridge - I agree with you that any accumulation under 6" now feels like a dusting. We've really been conditioned this winter, eh?

Hi Frida7 - 35.2" for February in 1899 would be the DCA record we'd have to beat for this month. We have about 28" so far (could not find updated stats yet for official monthly total though!)

Posted by: Camden-CapitalWeatherGang | February 12, 2010 3:01 PM | Report abuse

The snow is being dumped in the parking lot for the old DC Hospital. It can't go into the river because it would dam it up and cause flooding due to the huge quantity.

Posted by: bmp246 | February 12, 2010 3:07 PM | Report abuse

Besides the hospital parking lot, they are also piling it up under the Wilson Bridge.

Posted by: megamuphen | February 12, 2010 3:33 PM | Report abuse

Wunderground has up-to-date data on seasonal and monthly snowfall totals. Currently DC (Reagan Nat'l) is at 31.9" for Feb 2010, which is consistent with snow total reports put out by NWS, etc for each of the 3 weather events (Feb 2-3, Feb 5-6 and Feb 9-10). Individual storm numbers for DCA are 3.3", 17.8" and 10.8". Just go to and put in DCA for location and use previous day (in this case, Feb 11, 2010) as date, it will show daily detail plus various summary stats including monthly and season snow totals further down. IAD is code for Dulles, season total is showing as 75" (Feb 2010 = 47.9") if date set at Feb 10, but curiously the season total drops off to 72.8" (and monthly down to 45.7") if date set as Feb 11. Anyone know whether this a revision for Dulles snow total or just a data glitch? Earlier reports for individual storms from NWS point to the Feb 10 data as correct but I haven't checked other sources yet for possible revisions since.

Posted by: mlmcronin | February 12, 2010 3:53 PM | Report abuse

Yes, DCA has 31.9, so another 3.3 breaks the record for any month.

In January 1978 in Boston we got 22 inches of snow with 50 mph winds (a record at the time), then in February 27 inches with 90 mph winds (a new record at the time); then after 3 weeks' dry calm weather we got 9.2 in early March. Even in Boston, 9.2 is normally noticeable, but nobody noticed it that year. The next year, though, Boston had turned into Washington DC--even the mention of snow sent panicked people into the grocery stores. I think that will happen here next winter.

Posted by: doubtingdavid | February 12, 2010 4:01 PM | Report abuse

I also get the feeling, @doubtingdavid, that local governments will allocate way more than is necessary for snow plowing and clearing in next year's budget. Typical of government allocation: way too much, way too late.

You know as well as I do that next year we'll be lucky to get 20 inches the entire winter. But we'll have loads and loads of plows and salt ready!

Posted by: SWester2010 | February 12, 2010 4:13 PM | Report abuse


Posted by: ChickenLady | February 12, 2010 4:26 PM | Report abuse


Ian Livingston summarized the snow stats in yesterday's PM Update. So doubtingdavid is right that we are 3.3" away from the February(and all-time monthly) record for snowfall in D.C.

Posted by: CapitalWeatherGang | February 12, 2010 4:48 PM | Report abuse

Thanks for the February/winter snow statistics. This still promises to be an interesting winter...

Posted by: Frida7 | February 12, 2010 6:22 PM | Report abuse

OK... testing the skills of everyone here. Read an article that mentioned a chance of snow on Monday. It ended with a statement that a big storm may be coming a week after that (so.. about 9 days from now). Anyone see any indication of that at all? Crazy!!

Posted by: bornin1775 | February 12, 2010 8:56 PM | Report abuse

With the continual forecasts of snow, are you sure that Bill Murray hasn't become the weatherman on one of the local stations?


Just a thought...

Posted by: Paladin7b | February 12, 2010 10:45 PM | Report abuse


Yep, been looking long range and saw the system you mentioned. Need it to hit the 168-180 hour range (7-7.5 days) out. IF, you want to go witha computer guess this far out, it will be a bad storm. AGAIN, this is a guess at this time frame.

Posted by: wxsquid | February 13, 2010 1:59 AM | Report abuse

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