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Posted at 11:05 PM ET, 02/ 8/2010

Forget Snowmageddon, let's call it Wintergeddon

By Dan Stillman

More than 12" possible in places; gusty winds

* New storm polls: Tell us how much and name it | E-mail forecast *
* Winter Storm Warning Tues.-Wed. for most of metro area (map) *
* Making history? | Today's Q&A | Snowmageddon's incredible output *
* Watch out for ice dams | Measuring Snowmageddon's depth *
* Power outage maps for Dominion Electric | Pepco | BG&E *
* Outside now? Radar, temps & more: Weather Wall *
* News, traffic & storm coverage: Local home page | Get There *

CWG team snowfall forecast for Tues.-Wed. Confidence: Medium.

In many other winters, you might log on the evening before a storm to find us hedging or trending down from an earlier accumulation forecast. Not tonight, and not this winter. The winter of 2009-2010 just won't stop. Its next episode (shall we call it Snoverkill?) arrives tomorrow with more snow (possibly mixed with some sleet, mainly D.C. and south and east) and eventually gusty winds. The end result is expected to be another major snowfall with metro area accumulations from 6" to 16".


Could it be more or less than you're predicting? Confidence in this forecast is not as high as for the last storm, mainly because of uncertainties in when and where the storm will intensify as it moves up the coast. If it intensifies further south than we currently anticipate, then totals could be higher. If it intensifies too far north, however, then totals could be lower. Here is our full range of accumulation probabilities:

20%: Less than 6"
35%: 6-10"
35%: 8-16"
10%: 16"+

When will the snow start? Snow (possibly mixed with sleet at times, especially from D.C. toward points south and east) could start as early as around noon tomorrow, but would probably be on the light side through late afternoon.

When will it get really bad? Snow, or a snow/sleet mix especially for D.C. and south and east, is likely to become moderate to heavy in the evening and probably stay that way through Wednesday morning.

When will it end? Best estimate is around late afternoon Wednesday -- later north and east.

How bad will the winds be? During the day Wednesday, sustained winds may reach 25-35 mph, with gusts to near 45 mph possible. Assuming there is still snow falling, this could create blizzard conditions, and would likely take down some trees and power lines.

What about other forecast details? Highs only get to the upper 20s to low 30s tomorrow, and stall in the 20s on Wednesday. See Jason Samenow's forecast for Thursday through the weekend.

What if my power goes out? Power outages are again a major concern when considering the snow left over from the last storm, the new snow about to come and the strong winds expected with it. To prepare, here are some some tips from followers of our Twitter feed:

@Melvin_Frohike : battery powered "lamp."

@Sunfire2109: Write down the power co numbers NOW. I just lost power for a little while and realized I hadn't copied them.

@soleysomma: beyond obvious (batteries,flashlight,etc) warm blankets&clothes,radio,items for kids,charged portableDVD,carphone charger

@omgapony: Chrg phones, have battery op lites(not just flashlites), have canned food & manual opener, outdoors is a good fridge if nec

@brucecarton: Firewood

@sonjasugira: batteries. blankets. bread. and wine to stay extra warm.

@mamory: firewood, heat packs, and a big essential - a car charger for your iPhone!

Any other safety/preparedness tips? It wouldn't be a bad idea to shovel at least some of the snow off your deck or balcony (if you have either). And watch out for those ice dams!. Dr. Gridlock has the top 5 driving hazards, and check out these winter weather driving tips. Do you have a good safety/preparedness tip? Feel free to share with the group with a comment below.

When's your next update: 5 a.m. tomorrow.

SchoolCast (Tue.) FedCast (Tue.) capitol-black.jpgcapitol-black.jpgcapitol-gray.jpgcapitol-black.jpg

What do you think about all this snow? Love it? Tired of it? Let us know, or start a different conversation, with a comment below. And if you haven't already, join us on Facebook and follow us on Twitter.

By Dan Stillman  | February 8, 2010; 11:05 PM ET
Categories:  Forecasts, Updates  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: New storm polls: Tell us how much and name it...
Next: Forecast: Fierce winter storm to sock region



Posted by: shamuballeno | February 8, 2010 11:09 PM | Report abuse

Second! What the hell is "Woom?"

Posted by: gjjg4dgd | February 8, 2010 11:11 PM | Report abuse

Re: preparedness - this time we will grind plenty of coffee in advance. We were without power for 48 hrs in Alexandria... could boil water, but had to grind coffee beans with a rolling pin. We won't be making that mistake again.

Posted by: littlebs | February 8, 2010 11:13 PM | Report abuse

Change one thing in the tips - if you're facing time in a cold house, *don't* reach for the wine. It may make you feel better right then, but alcohol increases blood flow at the surface of the body, and will cause you to lose heat faster. That's NOT what you want when the power's out!

Posted by: fsd50 | February 8, 2010 11:14 PM | Report abuse

littlebs - sorry to hear your power went out last storm. Yet I have to chuckle at your preparedness tip; I am a coffee fanatic too. It would take priority for me as well ;)

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:15 PM | Report abuse

I don't know fsd50... I rather be inebriated with no power than sober with no power. The latter doesn't seem like much fun.

Posted by: nlcaldwell | February 8, 2010 11:15 PM | Report abuse

I know it's late, but my name suggestion...Son of Snowmageddon

Posted by: scottscottscott | February 8, 2010 11:17 PM | Report abuse

Wooo! Bring on the snow! I hope it's closer to 16 inches!

Posted by: gjjg4dgd | February 8, 2010 11:17 PM | Report abuse

Ok I don't know how you people manage to be the first commenters and excited about it. Do you just refresh the page until it shows up?? In any case, I say we name this storm "snoverkill". None of the sidestreets are plowed yet, and now won't be for awhile. Since last winter was my first in DC, I assumed I wouldn't need snow boots or ski pants or anything-uggs and rain boots would be sufficient. WRONG! Does anyone know of a place in the city (someplace accessible via underground-only metro) to get that kind of stuff since winter doesn't seem to be ending anytime soon?

Posted by: BruinGirl2001 | February 8, 2010 11:18 PM | Report abuse


Posted by: snowedin85 | February 8, 2010 11:18 PM | Report abuse

While I can understand where nlcaldwell is coming from, I feel very educated by fsd50! Who knew I would learn some biophysiology on the comment boards tonight? definitely makes me think twice before having some wine in the cold!

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:18 PM | Report abuse

The line goes right through the district... ISWYDT.

Posted by: Langway4Eva | February 8, 2010 11:18 PM | Report abuse

Sounds like the Prez Day 2010 storm is going to be too far south so after Wed. we may have to go for a week or longer without snow. Arrrgh!

Posted by: JerryFloyd1 | February 8, 2010 11:18 PM | Report abuse

When will there be a more certain prediction as to whether the low will intensify as predicted, or more north or south?

Posted by: sgc4 | February 8, 2010 11:19 PM | Report abuse

A good way to stay warm if you have a gas stovetop: My family lost power all of Saturday, so we covered the cabinets over the stovetop with aluminum foil to create a heat deflector and turned all four burners on and to maximum. It's much safer and more efficient (doesn't draw hot air out) than our wood-fire fireplace and produces about as much heat as a gas fireplace.

Posted by: antonioeliasiv | February 8, 2010 11:19 PM | Report abuse

BruinGirl2001 - I recommend the shopping complex at Columbia Heights. Marshalls, Target, Payless...they all seem to have boots to choose from. I had good luck there back in December. My wardrobe wasn't ready for this winter, either.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:20 PM | Report abuse


Posted by: snowedin85 | February 8, 2010 11:20 PM | Report abuse


Posted by: Murre | February 8, 2010 11:20 PM | Report abuse

It appears the weather gods have decided to replay 111 years ago for us...

Posted by: pmichaels1 | February 8, 2010 11:21 PM | Report abuse

PS, I am so glad the President's Day storm is staying to our south!!

Posted by: Murre | February 8, 2010 11:22 PM | Report abuse

And let me just say for the record-I consider myself a snow lover and wanted a snowy winter last year and was REALLY disappointed. Now I'm kind of suffering from snow fatigue since I don't seem to be prepared.

Posted by: BruinGirl2001 | February 8, 2010 11:22 PM | Report abuse

It's becoming a bit much for me, so all I can do is put in the HIGH SCHOOL MUSICAL dvd and hunker down. I wish I had a snuggie.

What about the rumors of another storm this weekend?

Posted by: ArlingtonGay | February 8, 2010 11:23 PM | Report abuse

I'm looking at the map and wondering how much snow this means for PG County (Largo/Capitol Heights/Bowie area)....does it mean 8-16 or 6-10

Posted by: lll1424 | February 8, 2010 11:23 PM | Report abuse

sgc4 - the dynamics of this system, and our medium-high confidenc, will likely remain into tomorrow. This system could unfold quickly and slightly differently, depending on so many tiny variations in a very dynamic atmosphere overhead. If I were to pinpoint a time after which few forecast changes would likely appear? 6 hours before the coastal low pressure is to form. That takes us well into tomorrow evening though--before our confidence becomes nearer "certain" for final accumulation numbers.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:23 PM | Report abuse

Wow, the difference between Bob Ryan and Topper is ridiculous. 6-12 or 10-20. Ryan sees more sleet mixing in. Boo!

Posted by: rocotten | February 8, 2010 11:24 PM | Report abuse

lll1424 & gjjg4dgd - I would advise you to consider the lower end of the accumulation predictions at this time. The final stage of the storm will likely dump more snow on Baltimore & points North/East of there--much more than Virginia, DC, and points around the Capital Beltway.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:26 PM | Report abuse

Bob Ryan is not only calling for sleet but for rain mixing in through Farifax and DC.. On the other hand, Dough Hill indicated that he may need to shift the heavy snow band even more south..

Posted by: ZmanVA | February 8, 2010 11:26 PM | Report abuse

"The line goes right through the district... ISWYDT."

That made me literally lol.
As much as I love snow I am hoping for less snow, I'm supposed to be going to NYC for Valentine's Day weekend with my girlfriend on Thursday. I would very much like the storm to not be big at all =[

Posted by: kirbybc | February 8, 2010 11:26 PM | Report abuse

Doug Hill....

:: Will we see blizzard conditions? "I think so" -- Wednesday for parts of the day.

:: Snow begins at 3p. Moderate by 11p.

:: Heavy snow throughout Wednesday morning.

:: The 16-20" band includes the northern third of Arundel, all of Howard, the northern quarter of Montgomery, everything in Frederick and Washington except right along the Potomac and all points north.

:: The 5-10"-snow/rain-sleet/snow band includes the southern half of Calvert, all of St. Mary's, the southern two-thirds of Charles, the southern half of Stafford, the very bottom edge of Fauquier and all points south.

:: The rest of us are in a 10-15" band.

:: "If anything, based on what I've seen tonight on the computer models -- if I change these bands at all, what I'll do is bring the 16-to-20-inch a little farther south and take the 10-to-15 a little farther south."

Posted by: MosesCleaveland | February 8, 2010 11:26 PM | Report abuse

We also see sleet mixing especially downtown and to the south and east.

Posted by: Jason-CapitalWeatherGang | February 8, 2010 11:26 PM | Report abuse

Power Outage Tips

Take a hot shower before you think the power might go out. Fill up bottles and tubs with water if you're on a well.

Have at the ready:
+flashlights, candles and/or oil lamps
+battery/hand-crank radio
+food: plenty of stuff to eat--peanut butter & jelly sandwiches... and easy-to-cook in the fireplace stuff like hotdogs, soup, etc.
+old-fashioned telephone
+favorite alcoholic beverages (optional)

Posted by: spgass1 | February 8, 2010 11:29 PM | Report abuse

@camden thanks i'll give it a shot-i've been meaning to go up there for awhile. the payless in adams morgan doesn't have winter shoes anymore. hopefully one of those stores will have something! otherwise it might be (and god knows how long it will take because my street isn't plowed).

Posted by: BruinGirl2001 | February 8, 2010 11:29 PM | Report abuse

rocotten - the Capital Weather Gang has also seen the wide variance in forecasts among TV meteorologists. This reflects how confidence is lower in this storm's progression, compared to earlier storms this season. We feel we've taken the middle of the road with higher confidence built into our forecast. Some mixing is likely. And snow will have a very hard time eclipsing the 16" mark until you get north & east of Baltimore.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:29 PM | Report abuse

@ BruinGirl2001: Just a little tradition carried over from the old site :)

For accuracy, let's put the totals given by media outlets together... anywhere from 4" - 24", 99% confidence. I feel job offerings a'comin...

Posted by: Sterlingva | February 8, 2010 11:29 PM | Report abuse

Thinking about going south on I-95 tomorrow morning to escape this. Would I be driving right through it? What path will the storm take?

Posted by: pxl4 | February 8, 2010 11:30 PM | Report abuse

Bob Ryan needs to retire; he really does seem to hate the snow. Hopefully BWI will stay on the low end of the accumulations and flights won't be cancelled on Thursday. I know it's a long shot, but at least we know regardless of how much BWI gets the measurement will be on the low end!

Posted by: DLO1975 | February 8, 2010 11:30 PM | Report abuse

I think someone upstairs finally realized that we had been short on snow these past six winters, and is deciding to make up for all six winters at once... yowza.

Posted by: MKoehl | February 8, 2010 11:31 PM | Report abuse cautious due to potential carbon monoxide poisoning!

Posted by: munch132 | February 8, 2010 11:31 PM | Report abuse

"Wintergeddon" seems a bit forced. How about we call it the Cyberdyne Systems Snowstorm Model 101. THE WINTERMINATOR.

The blizzard becomes self-aware at 2:14 am, eastern time, February 10. In a panic they try to pull the plug...

Posted by: the2belo | February 8, 2010 11:32 PM | Report abuse

Dear weather gods, please let this thing intensify further north. When my squad goes back to work Wednesday morning, I want to be able to go home after my shift!

Posted by: natsncats | February 8, 2010 11:33 PM | Report abuse

scottscottscott & BruinGirl2001 - thanks for the name suggestions ;)

antonioeliasiv - would such heavy usage of your gas stovetop produce a CO buildup? I would worry about the side effects of inside air quality :-/ yet I know options are limited in households without power; especially those with children. Fire risk & carbon monoxide posioning increase with major snows. ugh.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:33 PM | Report abuse

the Capital Weather Gang has done a great job forecasting storms this winter and i enjoy your commentary. However, as a bit of an amateur weather geek, I think you guys are off on this one. I'm more in the NWS, Topper, Doug Hill camp than the CWG, Sue Palka, Bob Ryan Group. Based on the models I've seen for this event and the current winter pattern,I think the metro is gonna get smacked. I guess we'll see...

Posted by: danog224 | February 8, 2010 11:34 PM | Report abuse

I'm already beginning to hope that the summer isn't as crazy as the winter this year. I really don't like thunderstorms.

Posted by: krosseel | February 8, 2010 11:35 PM | Report abuse

I've loved snow all my life, have really loved it since the Veterans Day Storm of 1987, my freshman year in college here in DC, but this winter has been absolutely mind-blowing. I've been lucky in that I didn't lose electricity during both Snowpocalypse and Snowmageddon, but am wondering if this next one will be the charm and plunge my apartment into darkness.

To whit: Flashlights w/extra batteries? Check.

Dominion VA Power phone number? Check.

Fully charged cellphone? Check.

Non-perishable food that I can cook on my gas stove? Check.

Lots of books for reading during the daytime? Check.

Wine (one glass ain't gonna hurt)? Check.

Posted by: Juan-John | February 8, 2010 11:35 PM | Report abuse

pxl4 - 95 South might be fine until dark tomorrow. Few worries, weather-wise, once you get past Richmond toward Petersburg.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:37 PM | Report abuse

Like px14, I also will be driving south on I-95 tomorrow, leaving the District about 10:00 a.m. Will I be driving into snow and/or freezing rain, or will I be able to get far enough south to beat the frozen stuff and encounter only rain? What was I-95 like today (Monday)? Mostly okay or still pretty bad?

Posted by: octamatilda | February 8, 2010 11:42 PM | Report abuse

I don't suppose we'd be as lucky driving up and down 81 tomorrow afternoon/evening?

Posted by: weatherface | February 8, 2010 11:43 PM | Report abuse

@CWG: Any clue on what the flight situations out of the area airports are going to be like? I have a 6 pm flight out of National to Canada on Tue. I am guessing ground conditions are not going to be bad by then, will they?

Posted by: krishnanswamy | February 8, 2010 11:44 PM | Report abuse

Those of you who are saying that you feel the accumulation amounts will be higher than what CWG are predicting--what are you seeing that leads you to believe this?

It seems that the CWG have taken into account as many variables as is possible at this point, and basically split the results down the middle. In other words, they're saying that we *could* get more, but that nothing indicates with any certainty at this point that we will. So, I'm just curious what you are seeing in the models that leads you to feel otherwise.

Posted by: ultrapop101 | February 8, 2010 11:47 PM | Report abuse

Whoa the gas stovetop idea sounds wildly UNSAFE to me. I don't imagine aluminum foil could protect cabinets for long. I suggest anyone in this dire condition strongly consider finding alternate arrangements by noon tomorrow to get through the next storm. A warming center, hotel room, or friend's sofa is a much safer way to stay warm and safe until your power comes back on.

Posted by: ArlingtonSnowGal | February 8, 2010 11:48 PM | Report abuse

Snowtorious B.I.G.

Posted by: danuva | February 8, 2010 11:49 PM | Report abuse

Langway4Eva - glad you saw how we detailed a lower accumulation for downtown DC. It is a micro/meso-climate that truly lowers snowfall accumulation by the same proportion for each storm. For Snowmageddon, spots downtown had only 19-21" vs 25" just above Rock Creek!

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:49 PM | Report abuse

Based on their skills and data-gathering, I would have to say that I have high confidence in CWG's forecasts.

Posted by: krosseel | February 8, 2010 11:50 PM | Report abuse

CWG: Great call at this point given the uncertainty! That said, I've done some comparisons with a similar "diving" closed low situation (Feb 5-7 1978) and noted these differences:

* This event is working with much more subtropical moisture. 850 mb temps and dew points in the deep south are significantly higher than in 1978. Thanks (or no thanks) El Nino :)

* The transfer low will be a bit stronger, even relative to the lack of arctic high pressure behind the entire system, much farther south than in 1978. That again may be courtesy of increased static instability with the subtropical jet. It will also be closer to the coast as it explodes right near Hatteras.

* The "nose" of 850 mb Theta-E will spend some time extending west through DC/Balt which should help enhance the deformation zone, even if winds up there turn NNE rather than the more favorable ENE.

* With thundersnow a possibility, especially considering the vertical velocity "nose" and even a period of convergence in/near peak dendritic growth areas (850 toward 600 mb), there could be some wild fluctuations. 20-24" would not be surprising anywhere within the 8-16" band.

Quite an interesting storm to follow. Have looked for a "pure" analog and could not find it; 1978 comes closest aloft, unless I'm missing one. Good luck, all!

Posted by: wxdancer | February 8, 2010 11:50 PM | Report abuse

@nlcaldwell, I agree completely that when one is power-less (in any sense), getting drunk is very apt to be appealing. I just wouldn't recommend it for winter outages of unknown length.

Posted by: fsd50 | February 8, 2010 11:51 PM | Report abuse

Ok, enough with the ultra-lame monikers for the snow events. Snowmageddon? That wasn't even funny or amusing the first 500 times someone used it, let alone now. Once again, just like "fist bumps," we should all be reminded that once the hilariously "out of it" president starts saying it/doing it, it's definitely not cool anymore.

Posted by: Nixonin08 | February 8, 2010 11:51 PM | Report abuse

krishnanswamy - I am very worried about and and all flights out of IAD/DCA after dark (5pm) on Tuesday.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:52 PM | Report abuse

iirc the fire in DC that injured three kids a few days ago was started by paper materials which were too close to a gas stovetop which was turned on for heat in the apartment. Please, people, be careful and make other arrangements if your power goes out and you have no heat!

Posted by: natsncats | February 8, 2010 11:52 PM | Report abuse

CWG - as you well know, you're well below the accumulation predictions of most other forecasters out there.

Any other year I would've said you were wrong, but since you've been spot on with every other storm so far this season, I'll go along with it. If you're right, you've got a follower for life. I really hope you're wrong though.


Posted by: 300_sq_ft | February 8, 2010 11:52 PM | Report abuse

@danog224 - thing is, having followed CWG for awhile now they seem to have a pretty darn good track record. At this point it would be very difficult for me to trust Topper or Doug Hill over what is predicted and discussed here. I mean, on this blog, not only do you get the forecast but a pretty detailed and ongoing explanation (questions answered throughout each thread) of why they are calling it that way.

I am very impressed with the CWG and have recommended this site to everyone I know who is interested in DC weather.

Posted by: bkkwarlock | February 8, 2010 11:53 PM | Report abuse

For anyone driving on I-81 after noon tomorrow, please be especially careful. I do not see that interstate being in nearly the good shape as I-95, or I-66, for that matter.

Posted by: Camden-CapitalWeatherGang | February 8, 2010 11:55 PM | Report abuse




Posted by: 300_sq_ft | February 8, 2010 11:55 PM | Report abuse

what are the odds that the above-ground metro stations would close in the early evening (between 5 and 5:30). That's when I get off work!!

Posted by: BH99 | February 8, 2010 11:57 PM | Report abuse

Thanks Camden! I was worried that the snow'd be close enough to cause trouble by then. I think I may sit tomorrow out.

Posted by: weatherface | February 9, 2010 12:00 AM | Report abuse

BH99 - I thought I heard on WTOP last hour that still many (at least 15) above-ground stations are closed tomorrow. Regardless, my analysis & even that of WTOP, concluded that weather would indeed impact above-ground transit after dark tomorrow. You have a decent chance of making it onto Metro by 530pm. But I wouldn't risk any later! Get there ASAP after work :)

Posted by: Camden-CapitalWeatherGang | February 9, 2010 12:03 AM | Report abuse


Posted by: BH99 | February 9, 2010 12:04 AM | Report abuse


Posted by: spankyman111 | February 9, 2010 12:04 AM | Report abuse

well i dont care.. i dont have a job :(

I will be sending resumes ....

Posted by: gympooltravel | February 9, 2010 12:07 AM | Report abuse

@CWG: in your probabilistic projections, the intervals for your middle two categories are overlapping. I'm guessing the lower should read 6"-10"?

Posted by: tippicanoe | February 9, 2010 12:07 AM | Report abuse

Actually, don't listen to Nixonin08. I, for one, love the snow monikers--keep 'em coming.

*fist bump*

Posted by: ultrapop101 | February 9, 2010 12:07 AM | Report abuse

oops - the lower one DOES read that. The next one... should be 10"-16"?

Posted by: tippicanoe | February 9, 2010 12:09 AM | Report abuse

I know - nearly everyone is dazzled by the scientific precision of the CWG "probability based" forecasts, and now DC spans 6" to 16" with someplace somewhere getting more than 12" - but did CWG actually intend to say "35% 6-10, 35% 8-16" -- am I the only one who thinks this makes no sense on a "probability" basis? No one else in the gang?? Anybody out there want to apply the 50% rule to this for me?? I guess there's a 70% chance of 8" to 10". Someday a post about the scientific method you have developed for making "probabilty based" forecasts would be great to see. (Or you could post a picture of the dart board!) I raised the issue before and heard how - "NWS uses probabilities, like a 40% chance of rain..." - that's not an appropriate analogy...but I give up. If people find it "extremely helpful," much like a placebo, it doesn't matter whether there is any substance to it.

Posted by: manatt | February 9, 2010 12:10 AM | Report abuse

@manatt: I think their probabilistic projections make perfect sense, and giving a sense of the distribution is far superior than the more simplistic projections other forecasters employ. (You are right about this instance though on the overlap; I would bet it's merely a typo on their part.)

Posted by: tippicanoe | February 9, 2010 12:13 AM | Report abuse


HUSH. You know what I meant. :-)

Posted by: 300_sq_ft | February 9, 2010 12:15 AM | Report abuse

littlebs @ 11:13pm - just spewed wine all over my laptop. You guys are troopers. Love your priorities. Of all the mistakes to make with power out... good luck to you on this next round, you deserve it. I'm not sure I'd have been smart enough to consider the rolling pin. Brilliant.

Posted by: bobosnow | February 9, 2010 12:18 AM | Report abuse


In this particular case, we were aiming to get the probabilities (meant for the general metro area) to match up well with the accumulation forecast map, which has about half of the area at 8-16" and the other half at 6-10". It's not always easy to be "clean" with the probabilities when giving a general sense for the area as a whole, but hopefully they communicate what we see the range of possiblities as being.

Posted by: Dan-CapitalWeatherGang | February 9, 2010 12:22 AM | Report abuse

We here in flyover country, Texas, pray that it will snow and snow and snow inside the beltway. Blizzards, and gigantic hail stones, tornados, flash floods, and if it be ordained, earthquakes.

Posted by: falconflight | February 9, 2010 12:23 AM | Report abuse

So I'm pretty much safe to bank on total closures for Wednesday as well, right? Thursday??

Posted by: SWester2010 | February 9, 2010 12:23 AM | Report abuse

@danuva HA!! Though I heard one of the news stations calling the last storm that. I like snowverkill/snoverkill better. A commenter on a previous CWG post suggested it. To me, at least for this storm, it seems more fitting.

Posted by: BruinGirl2001 | February 9, 2010 12:27 AM | Report abuse

manatt & tippicanoe - I am not the best statistician on the Gang (and I would be surprised if many of our average readers cared about these details? But I am happy to address!) - CWG wants to communicate a mean expectancy of 11" over our forecast region. Furthermore, a logarithmic scale helps display the large spatial variability one could expect with snow accumulations in our region for this particular storm. Our probability brackets help break it down into more digestible terms. These brackets indicate how widely divergent we think accumulations could be. The dynamics for this storm aren't going to be as easy to arithmetically convert as our last storm which delivered a fairly consistent liquid-equivalent shield of precip over the region. Too much has to gel together in the atmosphere this time around. And it may not even converge overhead our region. So we grouped lower accumulations together 6-10"; then, if energy components do converge overhead near DC, snow would quickly add up into the range of 8-16". After that, north of our forecast region, things could really take off in the 16-28" range. Ok I wasn't concise at all. And I can have someone more mathematically inclined on our Gang talk about logarithmic scales another time perhaps? I think our bracket choice was the best of both worlds. Including reasonable outcomes for our region's accumulation potential and question marks that remain with this storm energy.

Posted by: Camden-CapitalWeatherGang | February 9, 2010 12:27 AM | Report abuse

i hope this storm "fist bumps" us into the new snow record!

Posted by: snowedin85 | February 9, 2010 12:28 AM | Report abuse

falconflight, what is wrong with you?

Posted by: ultrapop101 | February 9, 2010 12:32 AM | Report abuse


i actually prefer your version, and may continue to use it in your honor. consider it a tribute.


i really can't make heads or tails of your post. is it meant to be ironic or sarcastic? if so, it's not funny at all. or are you seriously going to pray that it snows even more here? or was the prayer part a figure of speech but you really do want our weather to be even snowier than it already has been?

Posted by: spankyman111 | February 9, 2010 12:34 AM | Report abuse

snowedin85 - haha yet another fist bump reference tonight. But yes, this storm has a good chance to help DC tie (or beat) our all time seasonal snowfall record

Posted by: Camden-CapitalWeatherGang | February 9, 2010 12:36 AM | Report abuse

BH99 and other Metro goers
This might help you out, it shows the service available during inclement weather for metro

Posted by: kirbybc | February 9, 2010 12:40 AM | Report abuse

Hey Camden,

Just a quick question about the winds and "near blizzard conditions" it seems like with each storm the winds have been a little worse. From what I understand, if all the elements come together right this storm could have the lesser amount of snow compared to the other two big ones but more wind creating the most "blizzard-like" conditions. Is this right or will the winds be comparable to snowmageddon's winds?

Posted by: snowedin85 | February 9, 2010 12:41 AM | Report abuse

Camden, it's not an issue with using log scales (whose purpose here I understand); it's non-exclusive intervals in the overall table containing 4 probabilities that sum to 100% assigned to 4 non-exclusive categoiries (not the map predictions, which make perfect sense). If you're trying to make those 4 probability categories 'map' to the map for the comfort of the non-statistical public, well, that's fine, that's your call. Communication is your main job, so do it however you think best. But as a statistician, I see it as an error in presentation (not that most non-scientists would care). Anyway, you guys do a great job, so pardon my nitpick.

Posted by: tippicanoe | February 9, 2010 12:42 AM | Report abuse

@Camden - err, you mean Reagan National might get the 9.5 inches required to make it the snowiest winter ever? Out of just this storm? Considering how low they come in compared to, well, everyone else - that is almost scary. If Reagan is getting near 10, the rest of us really might get 16 or more.

Posted by: bkkwarlock | February 9, 2010 12:44 AM | Report abuse


I am honored. I think I should open up the 12 year Bacardi for this.

Oh. Right. Finished it during the last blizzard.

Posted by: 300_sq_ft | February 9, 2010 12:46 AM | Report abuse

@Dan, @Camden: seriously, just make the damn snow stop already, and no one will nitpick about these toMAto/toMAHto issues in the first place. Can't you do that?? ;-)

Posted by: tippicanoe | February 9, 2010 12:50 AM | Report abuse

falconflight - step away from the tea party convention, please....

Posted by: bobosnow | February 9, 2010 12:54 AM | Report abuse

snowedin85 - I think you've grasped the characteristics of this storm: greater wind, less snow. Wind gusts over 35mph and visibilities around 1/8 mile are all it takes to label a "blizzard" - even just blowing snow that's already fallen can create these conditions.

tippicanoe - thanks for understanding. Also see Dan's comment above mine. I was glad he weighed-in in a more concise manner!

bkkwarlock - I do think it is within reach. And don't panic, per se. Just see how widely divergent totals could be throughout our region for this storm; I think 9.5" is not out of the question for DCA while nearer 16" possible for BWI. I am happy with our accumulation map too. Especially how it keeps deep downtown DC (and DCA) in a lower accumulation band ;)

Posted by: Camden-CapitalWeatherGang | February 9, 2010 12:55 AM | Report abuse

I've been happy to see the last several snow "events" but this next one is making me nervous. I'm worried what all the new snow/ice may do to my roof and other possible negative effects. I really hope it's not as bad as predicted.

Posted by: bigwino24 | February 9, 2010 12:56 AM | Report abuse

haha tippicanoe. You might be right. And I am starting to fall into the camp of folks who had enough snow for one season. I wasn't exactly mentally prepared for a record snowfall winter! but, shh, don't tell anyone I am tiring of snow. It's still fascinating to see these textbook scenarios unfold for DC!

goodnight all.

Posted by: Camden-CapitalWeatherGang | February 9, 2010 12:59 AM | Report abuse

I do believe falconflight was trying to say that the world would be a better place if all those disasters and catastrophes were to happen to the nations capital - wiping out the 'politicians' would mean, in his peapod world, things would be better.

Ho hum. As a DC native, I'm gonna take the low road: hope your 'country' of Texas goes through it's worse drought this year, followed by major flooding. And don't come crying to Washington for help when it happens. Hypocrisy run rampant...

Posted by: vaguypost | February 9, 2010 1:15 AM | Report abuse

I agree with manatt. CWG’s “probability tables” are driving me nuts. And now they’re “aiming to get the probabilities to match up well with the accumulation forecast map.” I just cannot grasp what everyone else is apparently finding “extremely helpful.” An example, from Feb. 3’s afternoon forecast by CWG on the weekend’s storm:
“Here's the CWG team's metro area accumulation probabilities as of now:
10% chance: Less than 2"
20% chance: 2-6"
35% chance: 6-12"
35% chance: 12"+
(Probability of 12 inches or more increases around 5 to 10 percent north and west of the Beltway.)”
So everyone was dazzled by the scientific precision of CWG’s probability forecast, which, on 4/3, called for a 65% chance of zero to 12” of snow. As for Camden’s reply, yes, your average readers do care about these details. The ones I know are as confused as I am. Can anyone out there apply the 50% rule to this for me?

Posted by: Hoyas4Ever | February 9, 2010 1:25 AM | Report abuse

I'm addicted to your accurate and fun forecasts Gang - a question on when the storm will wind down. Will it go full force until 6 pm or just the final flakes tapering off then? I've got a 10:00 pm flight Wednesday night to visit the fiance in London and I'm already resigned to paying for a cab to Dulles since I'm sure public transportation won't be taking me there. Any hope that I won't spend the night at the airport? Only two planes pretty please?!?!

Posted by: dc1128 | February 9, 2010 1:26 AM | Report abuse

I must add that you guys really are doing a great job.

Posted by: Hoyas4Ever | February 9, 2010 1:28 AM | Report abuse

@Hoyas - Your post also shows a 70% likelihood of 6-12+ inches, which is what everyone ended up getting. This beats your 65% of 0-12

What I think is most important to take away from that particular scale is that we had a 30% chance of seeing less than 6 inches and a 70% chance of getting more.

Obviously we got more, just as predicted.

I don't understand your confusion.

Posted by: 300_sq_ft | February 9, 2010 1:30 AM | Report abuse

How come the map says 6-10" and then 8-16"? Should it overlap like that or be 6-10" and 10-16"?

Posted by: blasmaic | February 9, 2010 1:34 AM | Report abuse

First, I think CWG does a decent job of addressing the range of possible outcomes and the uncertainty. I especially appreciate the fact that you provide additonal explanation for your reasoning and address comments. But I think it is a mistake to assume your audience "doesn't care" or won't notice when things don't add up. Truthfully, that explanation is a bit offensive because it implies you're "dumbing down" the way you communicate your forecast even if it means it's scientifically disingenuous. More fundamentally, I don't see any scientific method for assigning the probabilities you list - it creates the appearance of precision when it's really a judgment call. (This isn't an issue just for the CWG as there are many instances where future projections are premised on assigned probabilities with little underlying substantive support.) As I've noted before, as a practical matter it's even less useful when the probabilities you pick are nearly even over a broad range of possibilities - unless that is meant to convey that you can't identify any scenario more likely than another, and therfore there really is no forecast. No need to loose focus on the bigger picture - large storm headed this way - but I do think you build credibility by getting the details right.

Posted by: manatt | February 9, 2010 2:09 AM | Report abuse

Long time listener, first time caller. Love the site. Just got done with writing a brief and was curious as to the rxn of folks to this new storm. I do like snow but this is killing me - I have so much backed up at work, and the kids are going to be in school until mid June. Is anyone really excited for this next storm?

Posted by: bethesda-rat | February 9, 2010 2:29 AM | Report abuse

Oh, Bruingirl2001, you are probably a little late. The timing for getting boots around here is usually Fall. There's a sporting goods store in the complex for the Pentagon City Mall - out by the Sur le Table and the Harris Teeter, not in the mall. The only REIs I know are not accessible by metro, really. If it is any consolation, I have boots but no snowpants -- it hadn't been a problem until this year. Thigh high snow? Here? But I'm buying snowpants through the internet, so this should be the last snowy winter for awhile. ;)

We were without power a good bit through the last storm. It was COLD. Leave your faucets dripping overnight if your power is out, because the last thing you want is your internal pipes in the house freezing.

Posted by: BadMommy1 | February 9, 2010 6:11 AM | Report abuse

So, Upper NW and Bethesda, these are in the higher accumulation band on your map, correct?

Posted by: Langway4Eva | February 9, 2010 7:14 AM | Report abuse

I like that 10%.

"Wintergeddon" not so much.

Posted by: ennepe68 | February 9, 2010 7:57 AM | Report abuse

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