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Posted at 2:00 PM ET, 01/30/2009

Next Week's Storm: Big Snow or Big Bust?

By Dan Stillman

* Warming Up? Full Forecast | Grading Our Inauguration Forecast *

Next Chance of Accumulating Snow: Late Monday-Tuesday
Probability of Accumulating Snow: 40%
Most Likely Potential Impact:

So, what can we tell you besides the old, "It might be snow, might be rain, might be nothing" line? Well, there are a few things we can say.

This storm, which is expected to emerge from the Gulf of Mexico early Monday and then head toward the mid-Atlantic and Northeast, has the potential to be the season's first big one for the I-95 corridor. Then again, there's also big-time forecast bust potential, which is why we're only willing to go for a 40% chance of snow accumulation and a 2-flake impact in our forecast above -- at least for now.

Keep reading for more analysis...

Model forecasts have already changed dramatically in just the past 24 hours -- yesterday, models were in fairly good agreement on an inland track that would likely mean more rain than snow for the big East Coast cities, including D.C. Today, they are in fairly good agreement on a coastal track (a track that some national forecasters saw as unlikely just yesterday) that could mean more snow than rain -- or could be too far off the coast to give us much of anything. As usual, the threat of ice can't be ruled out either.

Would there be enough cold air to support snow? Yes, as long as the storm center tracks along or just off the coast, which would allow the counterclockwise circulation around the storm's low-pressure center to pull cold air down from the north -- the cold air will not already be in place, as Sunday and Monday highs are expected in the 40s. If the storm tracks too far inland, however, we'd be looking at surface winds coming from a warmer, more easterly direction.

We're still more than 72+ hours away from this potential storm -- plenty of time for the models to fluctuate some more. We'll try to keep our forecast on an even keel as we stay on top of the situation.

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

By Dan Stillman  | January 30, 2009; 2:00 PM ET
Categories:  Snow Lover's Crystal Ball  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Grading CWG's Inauguration Forecast
Next: PM Update: A Few Snow Showers, Then Cold


So....say the track stays on course to give us snow. How much are we talking? I have milk, bread and TP, should I buy diapers (even though I don't have a baby) and sell them to the highest-bidding neighbors?

Posted by: phanieb | January 30, 2009 2:12 PM | Report abuse

Well it has the POTENTIAL, to be a 4 flaker for our area. And someone somewhere from Richmond to Portland ME will get that 4-snow flake storm. Will it be DC or not? Time will tell.

Posted by: jpl1019 | January 30, 2009 2:22 PM | Report abuse

Good question! It's speculative, but *if* we luck out and do get some snow, are we still talking potential of 12"/24"? That was the first figure I heard tossed out last Tuesday.

Here's hoping =)

Posted by: Alexandria2009 | January 30, 2009 2:27 PM | Report abuse

the gfs this morning had it come farther east giving us a much better chance for snow, but it also had it being weaker than previously thought. who knows at this point...only time will tell

Posted by: danuva | January 30, 2009 2:35 PM | Report abuse

Alexandria2009 -- Sure, 12-24" is possible with a perfect storm development and track. But knowing how rarely the perfect scenario occurs, at least as far as D.C. snow is concerned, I don't think you could put the odds of that happening any higher than about 20% this far out.

Posted by: Dan-CapitalWeatherGang | January 30, 2009 2:36 PM | Report abuse

Thanks! I am factoring in that we are "due" for a good snow (not that it affects the models or the storm) and I am keeping my eye on this one. Btw, CWG is awesome!

Posted by: Alexandria2009 | January 30, 2009 2:40 PM | Report abuse

I could sure go for a good snow though I agree that it's just too iffy to wish for the BIG ONE. That being said, the models do look more favorable for at least a "moderate" snow!

Posted by: maestrojmk | January 30, 2009 2:42 PM | Report abuse

danuva- i would way rather have a moderate snowstorm than a huge, cold , rainstorm anyday!!

Posted by: samdman95 | January 30, 2009 3:06 PM | Report abuse

I guess we'll know for sure by Wednesday... :P... but here's hoping for snow! **

Posted by: MKoehl | January 30, 2009 3:16 PM | Report abuse

Sunday/sunday nights models runs will be huge! If you were to take the models RIGHT NOW, The spread would be between a big hit or a miss. For us, Timing is a HUGE factor. Lets all hope that this becomes more then just a potential. IMO if things come together just right, I think its and easy 12+ MAYBE. I'm dreaming to see this headline on capital weather MAJOR SNOW STORM ON THE WAY!!! :)

Posted by: clintonportis17 | January 30, 2009 3:20 PM | Report abuse

Ha clintonportis17!!...just a few days ago you were telling me the GFS was full of it!

Posted by: worldtraveler | January 30, 2009 3:23 PM | Report abuse

The reality of the situation is that this will be a major snowstorm for the Appalachians, not DC. The GFS is doing its normal dance and should not be trusted. The far western model solutions were overzealous with rapid strengthening of the storm and more eastern track makes sense, but not far enough east to give us major snow. Sure we could give some backlash snows (several inches but that does not count as major). On a happy note, DC should get more snow than Boston from this storm.

Posted by: mciaram1 | January 30, 2009 3:25 PM | Report abuse

The GFS ensemble mean from 12z today looks pretty good for this area.

Posted by: Ian-CapitalWeatherGang | January 30, 2009 3:32 PM | Report abuse


I don't recall even mentioning the the GFS in my post above nor do I remember saying that days ago. I may have said ONE solution is crap but did not say the GFS was crap.


I don't think at this point you could say not DC. If we were to take the CMC as the final solution it would be a major snowfall even for DC. Honestly we have seen a large model change from yesterday so any one model or solution can not be taken seriously right now. Sunday will be the exciting model day or major disapointmen.

Posted by: clintonportis17 | January 30, 2009 3:36 PM | Report abuse

Ian - The link you provided looks like the map is getting old what with all those wrinkly lines on it. Does anyone have some anti-aging cream for our country?

Does that map look like it will snow? I'm meteorologically stupid.

Posted by: authorofpoetry | January 30, 2009 3:57 PM | Report abuse


The main thing to look at on that map is the blue lines. The bluer the lines over you, the better. The maps Ian posted show DC in the blue areas for most of the storm.

Posted by: JJones-CapitalWeatherGang | January 30, 2009 4:33 PM | Report abuse

JJones - Thanks alot! That absolutely helps me understand...much appreciated!

Posted by: authorofpoetry | January 30, 2009 4:45 PM | Report abuse

No matter what happens, the discussion about this storm has been fascinating (particularly in the accuweather forums). You have these people who strictly forecast 5 days out and stick to that even though models start changing. They are saying it is because of the volcano in Alaska making the information gathering planes change course and compromise the integrity of the data. I mean whether or not this is true - just wow.

I'm keeping up hope for a major snowstorm, but I'm also really enjoying the chase for amusement purposes.

And the SLCB always gets me excited!

Posted by: dotyt | January 30, 2009 4:58 PM | Report abuse

Wow. Correct or not, here's what I'd call an "interesting" approach to forecasting.

Posted by: Dan-CapitalWeatherGang | January 30, 2009 5:00 PM | Report abuse

Discussions I've read seem to think Henry M is completely throwing out models because it goes in line with his theory that this is a huge storm - that if the storm tracks east, it loses all the power it had originally. Could be a conspiracy theory. =-)

But really a lot of fun to watch it unfold. I love watching Henry M's videos - even if they are sensationalist.

Posted by: dotyt | January 30, 2009 5:05 PM | Report abuse

20% chance for a perfect storm is really not bad at all. At this point in time, I'm definitely happy with that.

Posted by: wecndo | January 30, 2009 5:15 PM | Report abuse

The important question: Will it snow enough that we can cancel school without the pres mocking us?

Posted by: bettylou1 | January 30, 2009 5:36 PM | Report abuse

The OBAMA may regret mocking us as DC will probably now have a KNICKERBOKER type storm and he will have to declare the area a national disaster. It will be the weather GODS raining (eeerrrrrr) snowing down on him.

Posted by: stinkerflat1 | January 30, 2009 6:04 PM | Report abuse

@ Dan I'd call statement you link to is not "interesting", it's just plain dumb

Snow Lovers

I'd place the odds now for a 50% chance of a significant snow storm in the DC-Metro region. So, depending on your perspective you can view this as the colloquial glass being half full or half empty

Here's the choice you (and I face)

1) be optimistic now and ecstatic if snowstorm verifies

2) be optimistic now and suffer utter disappointment if it's a bust

3: be pessimistic now and be overjoyed by the surprise of a snowstorm

4: be pessimistic now and feel satisfied that you didn't erroneously go overboard with hope

5: Avoid the psychological stress completely by ignorin the storm potential or lack thereof from this moment on and then look out the window Tuesday morning and think how last Friday (today's today) neither optimism nor pessimism had a damned thing to do with what ever you see through the curtains, - probably even less than whatever you're point spread now for the outcome of the Super Duper Bowl (which I really do ignore)

Posted by: SteveT-CapitalWeatherGang | January 30, 2009 6:49 PM | Report abuse

Wow, this is a classic case of "I reject your reality and substitute my own!"

"I have basically taken the model runs and threw them away because they are wrong."
--Henry M.

Daaaaaaang girl! Why don't you tell us what you REALLY think about the models? (HAHA...sorry. I couldn't pass that one up.)

I agree with you Steve T, that is a pretty dumb statement. It would be excellent if this storm did materialize into a large storm for us. Then Margusity would have to eat his reality substitution AND the fact that we got his big daddy storm. Ha!

I'm getting excited about the storm. Aside from being bummed out if the storm produces plain ole' rain, I enjoy rainy/cloudy weather, so it won't be a total loss for me (close to it, though, knowing that we had a chance at a good storm).

Posted by: weatherdudeVA | January 30, 2009 7:05 PM | Report abuse

You guys also have to take into consideration that even the biggest Gulf sorm moving up the coast will not give us snow unless the surface cold air is locked in place. That, of course, best occurs when a big Canadian high is north or northeast of us, funnelling in CAD (That's what happened a few days ago and delayed the changeover to rain that forecasters predicted in the didn't happen till late afternoon).

The position of the high to our north (if one exists), as well as the position/track of the low itself, will determine whether we get snow or rain (or a mix) with the next storm.

Posted by: MMCarhelp | January 30, 2009 7:42 PM | Report abuse

Good link Ian. Interesting stuff. Thanks!

Posted by: PoorTeacher | January 30, 2009 7:49 PM | Report abuse

@PoorTeacher and others viewing Ian's link to ensemble means

Be aware the ensemble mean is an atmospheric state that will (almost) never exist. It's an average of all possible solutions encompassed by an ensemble, in this case of 21 individual model runs.

In as non geeky terms that I can think of now, it's like characterizing the temperature today by the average of today's maximum and minimum. The average itself tells nothing about whether the max and min are close or widely different.

So what's missing in the charts is a measure of how much the individual forecast model runs differ from one another. Take my word for it that the differences are relatively small, so that, for example, the envelope of storm tracks (similar to envelope of uncertainty in hurricane forecasts) is not exceptionally large about the track for the ensemble mean.

Posted by: SteveT-CapitalWeatherGang | January 30, 2009 9:04 PM | Report abuse

After following Henry's blog over at Accuweather for the last year, I finally cam to realize that he is ALL hype when it comes to snowstorms. He often throws logic out the window.
Luckily, I found this site and am very impressed with the people that are on it.

Keep up the good work!

Posted by: bodyiq | January 30, 2009 9:42 PM | Report abuse


Probably the BEST comment I have ever seen about henry! He has just completly let the fustrations of this winter get to him and the models not giving him his "big Daddy". Him and the entire Accuweather staff jumped on this so called monster storm knowing at the time we were still about 8 days away. Honestly, I would not mind seeing a bust with this storm because MAYBE the hype kings of america (Accuweather) will learn there lesson but I dout it. Now we have JB on accuweather going around saying oh yeah its looking great for the east, for storm after storm now! Out of the 2 years I have followd him, He has been right maybe 5 times. Just like his guarantee that snow would be on the ground for Inauguration day. We know how that went lol.

Posted by: clintonportis17 | January 30, 2009 9:57 PM | Report abuse

"The OBAMA may regret mocking us as DC will probably now have a KNICKERBOKER type storm"

Sounds like a "shovel ready" public works project to me!

Posted by: fishman1 | January 31, 2009 12:16 AM | Report abuse

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