Network News

X My Profile
View More Activity
The new Washington
Post Weather website
Jump to CWG's
Latest Full Forecast
Outside now? Radar, temps
and more: Weather Wall
Follow us on Twitter (@capitalweather) and become a fan on Facebook
Posted at 5:00 AM ET, 02/11/2010

Snoverwhelming: Tracking another snow chance

By Jason Samenow

* Finally, a chance to dig out: CWG's Full Forecast *

Next Chance of Accumulating Snow: Monday-Tuesday
Probability of Accumulating Snow (1" or more): 55%

Though we're catching a short break from any storminess through the weekend, model data suggest we may have another potential snowmaker moving into the region on Monday.

A vigorous disturbance (or clipper) diving south on the polar jet stream will likely pass just to our south. This will place it in a favorable position to produce a period of light to moderate snow over the metro region Monday afternoon and/or night.

There is also some possibility it will interact with the development of an area of low pressure off the coast -- evolving in a similar fashion to yesterday's storm. While current data do not suggest as intense a storm would form, the overall set up and flow pattern in the atmosphere will be similar in some respects. So the potential evolution of this disturbance will need to be watched very carefully over the coming days.

As with any storm more than 48 hours away, accumulation estimates are very uncertain. Here's a preliminary look at accumulation probabilities:

45%: Less than 1"
30%: 1-4"
15%: 4-8"
10%: 8"+

Most likely: 1-3"

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

By Jason Samenow  | February 11, 2010; 5:00 AM ET
Categories:  Snow Lover's Crystal Ball  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: It's over, really
Next: Forecast: At last ... a chance to dig out!


Glad to hear the next snowfall, as of now, doesn't look huge. Here's hoping for a gradual melt!

Posted by: krosseel | February 11, 2010 5:01 AM | Report abuse

If they have to cancel school again on Tuesday, I may lose it.

Posted by: BadMommy1 | February 11, 2010 5:20 AM | Report abuse

Badmommy, I am with you 1000%. Is there some vindictive god that doesn't want the kids to learn?

Posted by: formerwxman1 | February 11, 2010 6:26 AM | Report abuse

Question for the CWG: what is causing this unusual weather pattern from a scientific perspective? Been living in this area since 1968 and don't recall these types of successive storms and patterns. This may have been debated and discussed on previous threads, so forgive if redundant..

Posted by: elizamil | February 11, 2010 6:37 AM | Report abuse

45%, that's the ticket. Less than 1 inch!!

Posted by: Murre | February 11, 2010 6:51 AM | Report abuse

Hi Guys! What was the forecast for the Friday and Tuesday storms beyound 48 hours? If I remember the Tuesday storm didn't "get big" in terms of predictions until late Sunday.

Snow has met expectations this year, usually in DC area, unless it's good snow (5" or above) predicted, the actual accumulations tend to underwhelm.

Posted by: superseiyan | February 11, 2010 8:11 AM | Report abuse

1-3 inches? In the next 24 hours it will slowly rise to 10-20 inches...we've played this game before.

Posted by: SA-Town | February 11, 2010 8:17 AM | Report abuse

What are the chances that my flight tomorrow night from Reagan to Florida will still be on? And will I be able to get back on Tuesday afternoon, now that there's a possibility for more snow?

Thank you so much for all of your posts and comments. As a Floridian, this has been nothing short of amazing, and I'm too obsessed with this website.

Posted by: gatorfan | February 11, 2010 8:18 AM | Report abuse

I like that 10%.

Posted by: ennepe68 | February 11, 2010 8:18 AM | Report abuse

Just want to say "thank you" for all your work and info on this site. I read it religiously and have not been disappointed yet.. and with all the links you set up for us, I have learned quite a bit. Keep up the good work!
Snow? More snow? It is a little scary... weren't we at this point last week at this time?? Thanks guys.

Posted by: flynns2 | February 11, 2010 8:32 AM | Report abuse

elizamil: Sometimes our weather gets stuck in repetitive patterns. Usually, it's with rain so we slowly forget the sequence of rainy weekends, or the minor episodes of flooding. This year, we have a very active southern jet providing a parade of storms while a block in the northern jet keeps the cold air locked in over the East Coast. The result is a stormy and snowy pattern. In 1996, we also had a sequence of snowstorms, but in that year, most of the snow on the ground melted before the next storm.

Posted by: Kevin-CapitalWeatherGang | February 11, 2010 8:32 AM | Report abuse

So long as we all have power and heat our family sees this as a once-in-a-lifetime event to remember for the rest of our lives.

I think it's time to head over to Fort Reno for sledding, don't you think?

Posted by: nativedc | February 11, 2010 8:41 AM | Report abuse

Is this (currently over Texas) what's heading our way? Is the question whether it'll lose all its moisture, or whether it will go off track and miss the mid-atlantic?

Posted by: superseiyan | February 11, 2010 8:44 AM | Report abuse

@superseiyan All the forecast models show what is over texas staying well south of us, hugging the gulf coast.

Posted by: RandC | February 11, 2010 8:46 AM | Report abuse

This is the link I was referring to:

Posted by: superseiyan | February 11, 2010 8:48 AM | Report abuse


RandC is right. The storm you're looking at should stay to our south.

Posted by: Jason-CapitalWeatherGang | February 11, 2010 9:12 AM | Report abuse

Um, how can one say "Most likely: 1-3"" when it already says 45% chance of less than 1"? That's less than the 30% for 1-4". I'm not trying to be smart - just curious.

Posted by: SCDowns | February 11, 2010 9:20 AM | Report abuse

On par with elizamil's question, I heard or read somewhere that the increased snow in this region is related to global warming. Specifically, that the release of moisture from the arctic ice caps is resulting in more of these storms forming. Does anyone know anything about this? I realize global "warming" isn't just about the actual rising temperature, but also disturbances in weather patterns that can, in some places, result in colder and snowier weather.

Posted by: Stats | February 11, 2010 9:20 AM | Report abuse

@ superseiyan, SA-Town
This next storm is a clipper, so its moisture-deficient nature should limit accumulations to

Posted by: Sterlingva | February 11, 2010 9:21 AM | Report abuse

Though it's a 45% chance of less than one inch, that leaves an overall prediction of a 55% chance of greater than one inch.....

Posted by: revision | February 11, 2010 9:24 AM | Report abuse

Hm, that was weird. It is supposed to say "limit accumulations to less than 5", pending coastal development..."

Posted by: Sterlingva | February 11, 2010 9:32 AM | Report abuse

Based on the southward bias of the models this year, I wouldn't be surprised if we saw a little something (>1 inch) out of the system on Saturday.

Posted by: bdeco | February 11, 2010 9:54 AM | Report abuse

"pending coastal development" -- THERE'S the kicker!!

Posted by: Akabang | February 11, 2010 10:17 AM | Report abuse

Once again, bdeco, your comment intrigues me. It does seem like there has been some bias in previous storm models and DC has been a bit of a magnet for storms.

But wasn't it the case with this last storm, Snowverkill, that the low was actually predicted by the models to form pretty much exactly where it ended up forming? Then the CWG based their more conservative predictions on the low forming in a position just north enough and in a manner for periods to dry slot the region and have some mixing, where NWS read the models to crush us? The truth ended up being somewhere between the two with the variable being how intense the storm became and how slowly it pulled out of the area.

Am I understanding that correctly and not sure exactly what that tells us from the trends of the models?

Posted by: DCcola | February 11, 2010 10:26 AM | Report abuse

As the CWG forecasters say, it's impossible to tell so many days in advance. Then again, after seeing this winter's pattern, if the forecast says "less than 1 inch" now, we'll get a foot of snow on Monday.

Posted by: pitchtorobert | February 11, 2010 10:30 AM | Report abuse

Yes, this is how the forecast started out the last time around, and again there is the possibility of picking up moisture from the coast - but it's still early yet. It remains to be seen whether the accumulation predictions will start creeping up as the new storm approaches!

Posted by: Frida7 | February 11, 2010 10:31 AM | Report abuse

Just a comment on my last post...I was taking into account predictions by all the forecasters, but I think CWG was more on the mark than most...that's why so many of us follow the blog and appreciate the clear and regularly updated info. provided.

Posted by: Frida7 | February 11, 2010 10:43 AM | Report abuse

Good comments here... regarding how our forecast for the last event fared, we're going to post an evaluation from our weather checker early next week.

Posted by: Jason-CapitalWeatherGang | February 11, 2010 10:52 AM | Report abuse

Anyway to hold this upcomng storm off for a week? We're heading to Colorado for a week of skiing on Mon and I know they'll have plenty of snow there.

I have no complaints about being snowed in here and I wouldn't want to miss anymore opportunities...I'm not done with this winter yet! :)

Posted by: DaveB2 | February 11, 2010 11:02 AM | Report abuse

All the latest GFS runs have shown some form of precipitation there, just not that much. What are the chances snow to liquid ratios are high with this storm bringing accumulations up past 1 or 2 inches?

Posted by: Dylan0513 | February 11, 2010 11:10 AM | Report abuse

Accuweather is estimating 3.1" for the 2/15. Won't work. We need 4.1" to hit 60" at DCA (unless IAD is willing to loan DCA some of its 75" inches).

The Baltimore total of 79.1" is mindboggling.

Almost as mindboggling: the stupid, careless things people are doing in the aftermath of this storm. Like the idiots who left their dog inside the front of the Glover Park Whole Foods this a.m. The dog bolted out the door and ran up and down Wisconsin Ave. for a while 'til they finally got it on the sidewalk. And yes, there was plenty of traffic!

Posted by: JerryFloyd1 | February 11, 2010 11:19 AM | Report abuse

@Kevin: Sometimes our weather gets stuck in repetitive patterns.

NONONONONONONONO! NO MORE SNOW! I put my foot down. We have our happy little all time record. no need to add to it, now is there?


Kim about to lose her mine due to the blidning whiteness fo the snow in Manassas

Posted by: ksrgatorfn1 | February 11, 2010 12:05 PM | Report abuse

It sounds like Monday's event is not the type that will cause major disruptions to air traffic, at least not as it is currently forecast. Is that a fair assessment?

I unfortunately have to make a decision by mid-afternoon tomorrow about whether or not to go on my trip this weekend =(.

Posted by: jahutch | February 11, 2010 12:34 PM | Report abuse

Seems to me I remember a somewhat similar pattern during the winter of I think 93-94, but it was all ice. Every 3-4 days we got a new mess to contend with. I remember sliding down my driveway after I fell trying to scrape more ice off my car, and grabbing the trailer hitch on the back of my mini-van to keep from sliding all the way into the street and down the hill ...

And I too would like a response to Stat regarding the effects of global warming on our weather patterns ...

Posted by: mamasan | February 11, 2010 1:29 PM | Report abuse

"There is also some possibility it will interact with the development of an area of low pressure off the coast."

Now that's scary.

Love your page.

Posted by: kperl | February 11, 2010 1:31 PM | Report abuse

Not sure which thread this question belongs in...


With the way the costal jet stream has been huggung the mid-east coast, is there a possibility that the system currently sitting over TX might surprise us and drop some precip on us if it doesn't head out to sea near the Carolinas? I know that the NAM and the GFS are not projecting that right now, but the theory seems to have some basis in recent history.

Posted by: Alexandria2009 | February 11, 2010 1:54 PM | Report abuse

I feel a bit like Roberto Duran fighting Ray Leonard. Might I suggest a name for this one?

Snow Más

Posted by: wandoctor | February 11, 2010 2:02 PM | Report abuse

woooohoooo! the snow is GREAT for sculpting, FINALLY. soon come....

Posted by: walter-in-fallschurch | February 11, 2010 2:22 PM | Report abuse

Would just love to say that for all you natives (and southerners) who spend 8 months outside in the oppressive heat and humidity - life is a Big B!!!! This is the best winter ever since moving from Manhattan over a decade a go - I just wish this was the norm every winter - from Oct. through March. Bring it on - I will never long for the typical DC weather - humid, hot, and horrendous...the air is clean, the freaks are at home and every one is covered up...WINTER IS BEST - SUMMER SUCKS!!!!

Posted by: Metropolized | February 11, 2010 3:01 PM | Report abuse

@ metropolized

I love snow too, but right now am aching from chopping ice off my roof.

Posted by: celestun100 | February 11, 2010 3:50 PM | Report abuse

CWG -- Thanks for the response -- you are correct in that we forget about our consecutive, rainy, weekends and those, too, are patterns. Love the info, keep it coming --


Posted by: elizamil | February 11, 2010 4:00 PM | Report abuse

Is there any established rule of thumb or relationship between daytime highs and how many inches of snow melts per day?


32 - 35 = 1 inch per day

35-40 = 3 inches per day

40 - 45 = 5 inches per day

I know that's really simple. There are lots of other factors such as sunshine and night time freezing. The 10-day forecast showing most daytime highs in the 30s and I'd love to know how much relief that implies we will we get. My dogs want their yard back (I probably have 45 inches back there.)

Posted by: kevin9 | February 11, 2010 4:12 PM | Report abuse

So since the storm is supposed to be centered slightly south of DC, are we looking at a bigger storm for the Richmond area?

Posted by: jwblake | February 11, 2010 4:37 PM | Report abuse

i can't really comment on those estimates you made except to say that sunshine makes a HUGE difference.

Posted by: walter-in-fallschurch | February 11, 2010 4:59 PM | Report abuse

I have lived here for 27 winters, and I can count on my thumbs the number of clippers that have given us a reasonable amount of snow. The most recent time was this past January, when DCA got 1 inch and Glover Park got 1.5. One other time years ago we got 3 or 4 out of one. In Boston, on the other hand, you could count on one or two per winter, with 5 or 6 inches not that unusual. The reason is that it's rare for them to go south of us down here, which they need to do for us to get any snow, and there's no good moisture source (in Boston they get a little from Long Island-Vineyard-Nantucket Sound).

Posted by: doubtingdavid | February 11, 2010 5:58 PM | Report abuse

Clipper systems almost never produce more than an inch or so around here. The LP system offshore is more troublesome.

Posted by: maus92 | February 11, 2010 6:22 PM | Report abuse

I live in Sydney, Australia and I have a friend in Nth Va - so this forum and associated webpages are great - hard to comprehend the disruption when today we are looking at 35 deg C in SYD.

I am coming over late March to visit - all this stuff will be finished by then??

Posted by: werdna | February 11, 2010 6:48 PM | Report abuse

Okay... newbie at some of this, but not at statistics. :) How can you say 'most likely' is 1-3". when 1-4" is 30% and under 1" is 45%...

What am I missing here?

Posted by: leesweet | February 11, 2010 7:39 PM | Report abuse

I am coming over late March to visit - all this stuff will be finished by then??

Posted by: werdna | February 11, 2010 6:48 PM

We may not have any storms in March, but we will surely have mounds of snow yet unmelted.

Posted by: waterfrontproperty | February 11, 2010 8:59 PM | Report abuse

As for the 1-3" "Most Likely" forecast -- it is easy enough to calculate expected snowfall amounts based on the probability distribution presented in the article (45% less than 1"; 30% 1-4", 15% 4-8"; 10% > 8"). Taking the low end of each snowfall amount group -- i.e., 0, 1, 4, and 8" --yields expected snowfall of 1.7". (0" x .45 + 1" x .30 + 4" x .15 + 8" x .10 = 1.7"). Taking high end of each group (using 12" as upper bound for the high snowfall group) yields expected snowfall of 4.1". Using the midpoint of each group -- i.e., 0.5, 2.5, 6 and 10 -- yields expected snowfall of 2.9". If anything, a "Most Likely" range of 1-3" seems a bit conservative given the probability distribution reported.

Posted by: mlmcronin | February 11, 2010 9:41 PM | Report abuse

I was just out there driving, everything seem under control. They were clearing-up --all the way to the pavement, which is in itself amazing by New York standards, say-- the fourth and ultimate lane on I 395. But I trust your idiotic gang will find a way to make it sound like another apocalyptic event before long.

Posted by: RegisUrgel | February 11, 2010 11:09 PM | Report abuse

"Stormagedon," "snoverwehlming." How about "capitalgangoofies" or "weathysterical gang?"

Posted by: RegisUrgel | February 11, 2010 11:19 PM | Report abuse

So you're saying theres a 10% chance! Woohoo!

Posted by: mramitanand | February 11, 2010 11:22 PM | Report abuse

Arlington County please come plow. NO phone or email response and NO snow clearance... so, how do you expect school administrative employees to report on time as required Friday? We have people shoveling the streets in our neighborhood -- hey County Board where should we send the bill?? -- oops I forgot this is Arlington, I'll pay my taxes and not expect anything in return.
Don Weber
2012 North Upland

Posted by: bogbug | February 11, 2010 11:38 PM | Report abuse

Uh oh...latest GFS/AVN model run shows an increased possibility of snowfall Monday pm...maybe 3 inches or more...

Posted by: Ayrwulf | February 12, 2010 12:05 AM | Report abuse


Anthropogenic Climate Change (ACC) is likely having some kind of an an effect. The higher average temperature readings all around the globe are showing there is more energy in the atmosphere now than the past ~2k years. So, if you remember in physics; temperature = energy. All the extra energy has to go somewhere. This excess results in more active weather around the globe. However, these storms are too localized for ACC to be the only factor.

These snow storms are actually more the result of a steady, yet moderately strong El Niño season (the warming of the Pacific Ocean, don't ask me why this happens, it just does) which has world-wide effects on local weather patterns for most of the globe. Some places are abnormally hot and moist, while other places can get abnormally cold and dry or any other combo of those things. We just happen to get the colder, wetter part of the deal.

If I've left anything out, just note that is is 5:30am atm. :)

Posted by: SpeedLimit186000 | February 12, 2010 5:37 AM | Report abuse

The comments to this entry are closed.

RSS Feed
Subscribe to The Post

© 2012 The Washington Post Company