FAILDC#

[stormtracker]

Timing will be critical to everything. The key, crux, turning point, lynchpin is that one factor.

18z runs will be telling.

[Scuddz]

Timing will be critical to everything. The key, crux, turning point, lynchpin is that one factor.

18z runs will be telling.

Imma put a triple-phasing boot up some azzes

[Fozz]

DT Final call

[mitchnick]

for our area, I think that's the right call by DT

I think he's a bit aggressive in NE from what I've seen on the models, but they seem to always pull one out of their azzes so he might be right

[PrinceFrederickWx]

I won't see it even if it does cause' I ain't gonna' be awake!

actually, these are the kind of events that Anne Arundel County does the worst of all the metro area, except maybe eastern Baltimore County

5 miles or less as the crow flies from mby they have an additional 300' and they have a shot at 1"+ imho, but not me

^This, basically

Typical climo storm pattern just like October, where about 30-40 mins away north and west will have snow where i'll be all rain. It doesn't upset me really, that's just how it is. I get mad when areas east and south get all the snow (i.e. 12/26/10) because that's ridiculous.

[psuhoffman]

FWIW, the LWX point forecast is calling for 3-7" around psuhoffman/Vortmax.

1-3" for me.

Tonight: Snow, mainly before 1am. Low around 29. Windy, with a north wind between 21 and 26 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 6 inches possible

THat is my NWS forecast for tonight... seems really bullish to me. I would go with 1-3" and the 3 seems a stretch right now even up here.

[Fozz]

Tonight: Snow, mainly before 1am. Low around 29. Windy, with a north wind between 21 and 26 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 6 inches possible

THat is my NWS forecast for tonight... seems really bullish to me. I would go with 1-3" and the 3 seems a stretch right now even up here.

I think you'll get about 3", but probably not 5-6.

[mitchnick]

there's our only shot at snow tonight in western TN

http://radar.weather.gov/Conus/southmissvly_loop.php

[usedtobe]

^{Is there any historical reference to this kind of setup that would lead to the storm outperforming?}

Not that I know of, the 850 and surface tracks now stink, too far north and west.

[catoctin wx]

Like the last storm, I'm thinking that the "Frederick Valley" (which I am determined to coin) will see no accumulation, while the surrounding area get's a few inches.

Just a refresher on the pain we saw around here:

[Bob Chill]

^{Is there any historical reference to this kind of setup that would lead to the storm outperforming?}

Not really. Our only hope is a heavy band setting up somewhere as the ull swings through. Even with that, an inch or 2 at best. At least around the cities. T-1 is a really good call for all the metro areas.

[Solo2]

Like the last storm, I'm thinking that the "Frederick Valley" (which I am determined to coin) will see no accumulation, while the surrounding area get's a few inches.

Just a refresher on the pain we saw around here:

My thoughts exactly.

[Solo2]

... Winter Weather Advisory remains in effect from 7 PM this

evening to 1 am EST Thursday...

* precipitation type... rain changing to locally heavy snow.

* Accumulations... 2 to 4 inches of snow. 3 to 5 inches across the

higher ridges.

* Timing... rain changes to snow in the evening. Heaviest between

8 PM and midnight.

* Temperatures... falling to the lower 30s early this evening. Low

temperatures tonight will range from the lower 20s along the

ridges to near 30 in the valleys.

* Winds... northwest 15 to 25 mph with gusts up to 40 mph.

Precautionary/preparedness actions...

A Winter Weather Advisory for snow means that periods of snow

will cause primarily travel difficulties. Be prepared for snow-

covered roads and limited visibilities... and use caution while

driving.

Up from 1-2 earlier this morning....

[Ian]

NWS gonna need some luck with those forecasts around here...

[AlYourWxPal]

Like the last storm, I'm thinking that the "Frederick Valley" (which I am determined to coin) will see no accumulation, while the surrounding area get's a few inches.

Just a refresher on the pain we saw around here:

Yea, Frederick seemed to be on the low end with the last one. I'm saying 1-3 for the valleys and of course the Catoctin's will likely end up with more.

[mitchnick]

I will say this much

radar has some real strong echoes but the qpf is relatively unimpressive for those echoes imo

[aldie 22]

NWS gonna need some luck with those forecasts around here...

They could verify out this way...they have us down for 1-2"...I don't think matching the 1.2" total form the October storm is unreasonable...maybe it is but we will see in about 12 hours I guess

[Fozz]

They could verify out this way...they have us down for 1-2"...I don't think matching the 1.2" total form the October storm is unreasonable...maybe it is but we will see in about 12 hours I guess

Facebook:

Capital Weather Gang

Note: we think NWS forecast of 1-2" in N burbs is overdone. Maybe 1" of sloppy snow mainly on grassy areas

[Ian]

They could verify out this way...they have us down for 1-2"...I don't think matching the 1.2" total form the October storm is unreasonable...maybe it is but we will see in about 12 hours I guess

More possible there.. and 1" is not IMPOSSIBLE here but not very likely either. NWS does this all the time... ups last minute then ends up wrong.

[WinterWxLuvr]

Nothing is written in stone. Forecasts are forecasts, regardless of who makes them. Obviously some can come up with a much better forecast than others.

When it comes to snow, I think everyone will agree that 1 or 2 degrees can make a tremendous difference. All of us think we have a good idea of what will happen tonight, but we don't know. We form those ideas based upon experiences, usually things don't go our way. But, it can happen.

The NAM made a pretty good jump in its forecast of snow for the areas to my east/southeast (DC) and to my NE (Frederick) as well as my area. I know that everybody makes fun of the snow maps, but they are generated as the result of what is probably a pretty sophisticated computer program. Obviously, it sees something as being better for snow than it did in its last run. Mean anything? Who knows. That's the point. None of us do. We just have to wait and see. Probability? Doesn't go our way. Guaranteed? Not a chance.

[Ian]

Nothing is written in stone. Forecasts are forecasts, regardless of who makes them. Obviously some can come up with a much better forecast than others.

When it comes to snow, I think everyone will agree that 1 or 2 degrees can make a tremendous difference. All of us think we have a good idea of what will happen tonight, but we don't know. We form those ideas based upon experiences, usually things don't go our way. But, it can happen.

The NAM made a pretty good jump in its forecast of snow for the areas to my east/southeast (DC) and to my NE (Frederick) as well as my area. I know that everybody makes fun of the snow maps, but they are generated as the result of what is probably a pretty sophisticated computer program. Obviously, it sees something as being better for snow than it did in its last run. Mean anything? Who knows. That's the point. None of us do. We just have to wait and see. Probability? Doesn't go our way. Guaranteed? Not a chance.

the 850 low is still in a terrible spot.. the 500 vort is not great either other than being strong. plus it's all hauling. we don't generally do well on the backside.. especially if it only snows for 2 hours -- though you're obviously in a better position than most of us. the clown maps are useless.. no one is getting 10:1 ratios except maybe a mountaintop somewhere.

[RodneyS]

Out of curiousity which November storm is in the top 10 at IAD?.

November 30, 1967, when 11.4 inches fell, placing it 10th in terms of monthly snowstorms at Dulles. However, this is somewhat of a technicality because the seventh greatest snowstorm in IAD history occurred December 31,1970-January 1, 1971, with 8.5 inches falling on New Year's Eve and 6.9 inches falling on New Year's Day, for a total of 15.4 inches. That is the only top ten storm in either DC or IAD history that took place in two different calendar months, and so I did not count it in the top ten monthly storms at IAD (it was only 9.3 inches at DCA). I also now see that I missed the December 25-26, 1969 snowstorm at Dulles, which dropped 12.1 inches, placing it 9th on the all-time IAD list. So, the corrected number of top ten storms by month at Dulles, excluding the 1970-71 storm, is: November, 1; December, 2; January, 1; February, 5; and March, 1. If the 1970-71 storm is credited half in December and half in January, the top ten at Dulles becomes: December, 2.5; January 1.5; February, 5; and March, 1. The top ten in DC history remain: December, 1; January 2; February, 7.

[WinterWxLuvr]

the 850 low is still in a terrible spot.. the 500 vort is not great either other than being strong. plus it's all hauling. we don't generally do well on the backside.. especially if it only snows for 2 hours -- though you're obviously in a better position than most of us. the clown maps are useless.. no one is getting 10:1 ratios except maybe a mountaintop somewhere.

Do the snow maps not account for surface temps? Also, can't rapidly falling precip also create rapidly falling temps?

I'm smart enough to know that I'm using wishful thinking here. I would just love it though if our whole area woke up to a surprise.

[WVclimo]

I had 4" on 10/29 from .80" liquid falling as snow. I'd expect the same type of ratios tonight, so halve whatever falls once the changeover occurs.

[MN Transplant]

Do the snow maps not account for surface temps? Also, can't rapidly falling precip also create rapidly falling temps?

I'm smart enough to know that I'm using wishful thinking here. I would just love it though if our whole area woke up to a surprise.

It isn't all about the surface either. In the snow growth areas of the cloud, we are going to be barely below freezing, so the ratios will not be friendly. It looks to me like the NAM wants to paint about 0.1" QPF of snowfall (for me) after the switch at 4z. At low ratios and a warm and wet surface, I can't see much more than what collected in October. It may be pretty in the sky though.

[ravensrule]

November 30, 1967, when 11.4 inches fell, placing it 10th in terms of monthly snowstorms at Dulles. However, this is somewhat of a technicality because the seventh greatest snowstorm in IAD history occurred December 31,1970-January 1, 1971, with 8.5 inches falling on New Year's Eve and 6.9 inches falling on New Year's Day, for a total of 15.4 inches. That is the only top ten storm in either DC or IAD history that took place in two different calendar months, and so I did not count it in the top ten monthly storms at IAD (it was only 9.3 inches at DCA). I also now see that I missed the December 25-26, 1969 snowstorm at Dulles, which dropped 12.1 inches, placing it 9th on the all-time IAD list. So, the corrected number of top ten storms by month at Dulles, excluding the 1970-71 storm, is: November, 1; December, 2; January, 1; February, 5; and March, 1. If the 1970-71 storm is credited half in December and half in January, the top ten at Dulles becomes: December, 2.5; January 1.5; February, 5; and March, 1. The top ten in DC history remain: December, 1; January 2; February, 7.

Thank you very much for all that info, so according to the revised stats my comment about the monsters being in December and mainly February especially at IAD are true.

[Ian]

Do the snow maps not account for surface temps? Also, can't rapidly falling precip also create rapidly falling temps?

I'm smart enough to know that I'm using wishful thinking here. I would just love it though if our whole area woke up to a surprise.

Most or all of the public ones spit out a 10:1 ratio once it's accumulating snow. I think there are some that can be modified but most are that standard.

The storm is just moving too fast for any real surprises IMO. The features in Jan were well southeast so we were in snow longer with better dynamics. The only real overperformer on the backside I can think of recently is Feb 9-10 2010 and it was crawling as well. There just won't be much time around 95 at least... Even an hour of heavy snow probably accumulates less than some think after all the rain and with marginal temps. But you're in a better spot than many of us.

[Fozz]

Thank you very much for all that info, so according to the revised stats my comment about the monsters being in December and mainly February especially at IAD are true.

I agree for February, Naso much for Dec.

It's just that we've had a lot of good Decembers in the past 10 years, but getting a major snowstorm in that month is rare, moreso than it is in January.

[mitchnick]

GFS really gives the the metro areas nothing considering marginal temps imho

top link shows the 850 line and 6hrs qpf total at 15 hrs while bottom link shows 3 hrs qpf for 3 hrs ending 18 hrs; after 18hrs, it's done

http://mag.ncep.noaa...el=&imageSize=M

http://mag.ncep.noaa...el=&imageSize=M

[Ian]

I agree for February, Naso much for Dec.

It's just that we've had a lot of good Decembers in the past 10 years, but getting a major snowstorm in that month is rare, moreso than it is in January.

Jan and Feb are our snowstorm months. The records at IAD are too short to draw much from them. I have every snowstorm on record for DCA in a file and Jan/Feb are pretty much on par with the other months trailing.