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November 2011 Obs/Forecasting Discussion

WxUSAF

By WxUSAF,
in Mid Atlantic

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WinterWxLuvr

WinterWxLuvr

Posted
Posted

Yes I know it's in fantasy land, but we don't have much else to track...GFS has a very interesting setup 276-312hr. Big shortwave digs and partially phases with southern stream energy and pops a coastal. Of course it's a total fish storm, but the setup is pretty good.

Big north Atlantic ridge (despite the + or neutral NAO) keeps the SE ridge at bay this run. Brakes down the PNA at the end of the run, but is otherwise a pretty cold run (especially compared to what we've been having).

Well, it certainly is looking more and more like the temps will return to at least seasonal, perhaps below here and there. It may not be tracking snow events, but its a step in the right direction. Now if we could actually rely upon the models past a few days.

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RodneyS

RodneyS

Posted
Posted

Random stat:

DCA has hit 60° for 10 consecutive days. The only times that this has happened in the second half of November previously was in 1931 and 1979. Both of those periods were more impressive, though, with a majority of each streak in the 70s.

Thanks -- you have a terrific database. :thumbsup: I note that the 1931-32 meteorological winter (D,J,F) in DC was the warmest of all time, with an average temperature of 44.6 degrees and a whopping one inch of snow. However, March 1932 averaged only 40.0 degrees, making it the 19th coldest March of all time and the coldest month of the season, and 4 inches of snow fell. The 1979-80 meteorological winter was also relatively warm in DC, at 39.0 degrees (32nd warmest), but with 13.7 inches of snow. March 1980 continued slightly warmer than average, at 46.2 degrees (57th warmest), but DCA still recorded 6.1 inches of snow. It's also interesting to note that 1979 was the last time that snow fell in October in the DC area prior to this year, with 0.3 inches recorded at DCA and 1.3 inches at IAD.

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usedtobe

usedtobe

Posted
Posted

Yes I know it's in fantasy land, but we don't have much else to track...GFS has a very interesting setup 276-312hr. Big shortwave digs and partially phases with southern stream energy and pops a coastal. Of course it's a total fish storm, but the setup is pretty good.

Big north Atlantic ridge (despite the + or neutral NAO) keeps the SE ridge at bay this run. Brakes down the PNA at the end of the run, but is otherwise a pretty cold run (especially compared to what we've been having).

Trouble is the ensemble mean doesn't much like the idea and keeps slightly above normal heights over the southeast in that time frame. It doesn't seem to like the gfs.

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WxUSAF

WxUSAF

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Posted

Trouble is the ensemble mean doesn't much like the idea and keeps slightly above normal heights over the southeast in that time frame. It doesn't seem to like the gfs.

Indeed. The mean looks like it has the same idea (trying to phase the northern and southern stream s/w's) at 276-300, but then it totally loses it. The individual ensemble members all seem to have the same players on the field, but handle everything a bit different. About 3 look similar to the Op in timing and phasing, some have the northern stream s/w outrun the southern stream or have a kicker come in and prevent a phase, some leave all the southern energy back in the 4 corners. Most do have some solid N-Atlantic ridging for most of the run however.

Worth keeping an eye on it...since there's nothing else to watch except perhaps post-frontal flurries in a week's time.

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WinterWxLuvr

WinterWxLuvr

Posted
Posted

I challenge you to find something good in the latest runs. Good meaning signs of a sustainable good pattern.

I challenge you to find a long range model that is correct 25% of the time at day 7-10 or beyond.

If someone posts a long range solution that is cold or snowy, it is scoffed at. Yet, when the long range looks bad it's somehow given more validity.

The long range (anything beyond 5 days) now, for a change, is at least showing some possible seasonable cold. That's a step in the right direction.

It may not work out. It may. Either way, what happens or doesn't happen won't be because a computer said it would.

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Bob Chill

Bob Chill

Posted
Posted

this might last for one run +pna -nao

post-4-0-45109600-1322594369.gif

Hey, nice look there! At least for the next 8 hours or so.

I challenge you to find a long range model that is correct 25% of the time at day 7-10 or beyond.

If someone posts a long range solution that is cold or snowy, it is scoffed at. Yet, when the long range looks bad it's somehow given more validity.

The long range (anything beyond 5 days) now, for a change, is at least showing some possible seasonable cold. That's a step in the right direction.

It may not work out. It may. Either way, what happens or doesn't happen won't be because a computer said it would.

I 100% agree with you about models @ 5+ days out. The odds of a solution being really accurate become really slim pretty quickly. My challenge was more for the large scale pattern and not any one system in particular. Every run of the ensembles has been showing a +AO/NAO and the +pna being very short lived before going back to negative. The models are half decent at forecasting these 3 indices in the lr even at 14 days out. IMO- there is next to no chance at a solid threat to track over the next 15 days.

Even before I start to analyze a model run, I'll hit these three links first so my expectations are proper:

http://www.cpc.ncep....a/nao.sprd2.gif

http://www.cpc.ncep....ex/ao.sprd2.gif

http://www.cpc.ncep....a/pna.sprd2.gif

I'm not knowledgable enough to get into the mjo, epo, and all that stuff but these 3 indices are a great place to start when looking into long range potential.

I'll never rule out a perfect little setup that sneaks something our way but I think we're stuck in a particularly bad longer term pattern if you want snow. The only thing that could make it worse is if the se ridge becomes stable and bulges on us. It's really not bugging me at all though because most of us have lived here quite a while and were very used to this kind of stuff. I'd much rather have a patter like this delay the onset of good winter weather than cost us 4-6 weeks in the heart of it.

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mitchnick

mitchnick

Posted
Posted

Hey, nice look there! At least for the next 8 hours or so.

I 100% agree with you about models @ 5+ days out. The odds of a solution being really accurate become really slim pretty quickly. My challenge was more for the large scale pattern and not any one system in particular. Every run of the ensembles has been showing a +AO/NAO and the +pna being very short lived before going back to negative. The models are half decent at forecasting these 3 indices in the lr even at 14 days out. IMO- there is next to no chance at a solid threat to track over the next 15 days.

Even before I start to analyze a model run, I'll hit these three links first so my expectations are proper:

http://www.cpc.ncep....a/nao.sprd2.gif

http://www.cpc.ncep....ex/ao.sprd2.gif

http://www.cpc.ncep....a/pna.sprd2.gif

I'm not knowledgable enough to get into the mjo, epo, and all that stuff but these 3 indices are a great place to start when looking into long range potential.

I'll never rule out a perfect little setup that sneaks something our way but I think we're stuck in a particularly bad longer term pattern if you want snow. The only thing that could make it worse is if the se ridge becomes stable and bulges on us. It's really not bugging me at all though because most of us have lived here quite a while and were very used to this kind of stuff. I'd much rather have a patter like this delay the onset of good winter weather than cost us 4-6 weeks in the heart of it.

during the "good" winters, those ensembles for the AO and NAO are always too high....this year, the exact opposite

bastids

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WinterWxLuvr

WinterWxLuvr

Posted
Posted

Hey, nice look there! At least for the next 8 hours or so.

I 100% agree with you about models @ 5+ days out. The odds of a solution being really accurate become really slim pretty quickly. My challenge was more for the large scale pattern and not any one system in particular. Every run of the ensembles has been showing a +AO/NAO and the +pna being very short lived before going back to negative. The models are half decent at forecasting these 3 indices in the lr even at 14 days out. IMO- there is next to no chance at a solid threat to track over the next 15 days.

Even before I start to analyze a model run, I'll hit these three links first so my expectations are proper:

http://www.cpc.ncep....a/nao.sprd2.gif

http://www.cpc.ncep....ex/ao.sprd2.gif

http://www.cpc.ncep....a/pna.sprd2.gif

I'm not knowledgable enough to get into the mjo, epo, and all that stuff but these 3 indices are a great place to start when looking into long range potential.

I'll never rule out a perfect little setup that sneaks something our way but I think we're stuck in a particularly bad longer term pattern if you want snow. The only thing that could make it worse is if the se ridge becomes stable and bulges on us. It's really not bugging me at all though because most of us have lived here quite a while and were very used to this kind of stuff. I'd much rather have a patter like this delay the onset of good winter weather than cost us 4-6 weeks in the heart of it.

I hear you on the indices. I'm not knowledgable enough to even be talking about those either, but I will have to point out that those forecasts are computer modeled as well.

I'm just glad to see any sort of "improvement" in the pattern. That ridge along the west coast is a tiny step toward the "better" pattern, in my know nothing opinion. I don't ever expect to look at the models and see a "great" solution, and if I did see it, I wouldn't believe it. I just try to enjoy what little positives that are there, when they are there. I feel like we are going to "cool" down, and I see that as a positive first step.

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Bob Chill

Bob Chill

Posted
Posted

during the "good" winters, those ensembles for the AO and NAO are always too high....this year, the exact opposite

bastids

I know what you mean! You figure they could just tune up the programming a little and increase accuracy.

I really like using those forecasts to indentify changes and trends. When it looks like a bunch of spaghetti you know not to focus too much on the LR but when things are clustered it gives pretty good insight to where we are headed.

I'm waiting for the first indications that positive ao/nao pattern is breaking down. I'm hoping we see the obvious trend downward in the forcasts somewhere in the next 15 days or so. Then maybe.....just maybe.....they flip negative and stay for a while. It's quite unusual for them to both be positive for so long. Heck, it's been since mid to late august for god sakes.

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usedtobe

usedtobe

Posted
Posted

12z ens not far off of the op, need that ridging a little further west

post-4-0-50046700-1322602229.gif

No the mean isn't and is a nice step in the right direction though the pacific looks kinda bad with the low heights over AK and the higher than normal ones stretching e-w to the south. That's a positive epo which is a change from the negative epo the models ahd been showing recently.

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Ian

Ian

Posted
Posted

12z GFS doesn't quite buy the 0z Euro's idea of a Miller B bomb, but keeps some hope alive for anafrontal flurries after the big cold front on the 6th. December 5th-ish rule invoked?

berk is on it.. which means it probably wont happen ;)

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