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Looking towards the beginning of December

CoastalWx

By CoastalWx,
in New England

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HM

HM

Posted
Posted

The Christmas warm-up, at least in my mind, was largely based upon a normal progression of tropical forcing as model guidance had depicted a few weeks ago. The MJO was originally progged to be entering phases 1-2 for early December, then propagating into p3 by late December, which would've meant higher chance for a torch. Now it's apparent the MJO isn't cooperating and it's likely to lollygag around the COD for the next week or so, then make some progression toward phase 1/2, which by the second half of December, are colder phases.

Since the warm-period's occurring now as the whole MJO timing has changed, the Christmas torch isn't going to occur unless we just continue a terrible pattern through New Years.

Current -OLR anomalies near the dateline are fairly favorable, and certainly way better than last year. Additionally we've got the AO on our side, the NAO is unlikely to remain positive for a long duration given the state of the arctic, and if we can eventually get some tropical forcing help, we'd be in good shape for Dec 15-30 period.

This isn't a bad map IMO:

I had a list of reasons why December could blow torch or why it could turn into a La Nina-gradient pattern / SE ridge in some other long-winded thread that I don't feel like searching for right now. But, there were more reasons than Tropical Forcing / AAM.

I don't think the OLR placement is good though and the stagnant forcing will allow for a semi-permanent Hadley Cell in W PAC and strengthened westerlies with East-Asian Jet. This isn't last year's setup by any means but it will aid in the -PDO type circulation to be enhanced for a while.

Finally, there is more to the Tropics than predicting an octant surge of the MJO. It wasn't that simple for December's possible outcomes, other than the beginning of the month.

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ORH_wxman

ORH_wxman

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Not at all, agreed. I do remember 2008 and how it looked on models which is also why I mentioned these SWFE type deals won't be seen like 2-4 weeks out. They sort of spring up on you all of the sudden. Remember how the NYE 2008 deal was like 1-2" and then rain? That thing was a 6-8hr dendrite dump here while Sam was nude in the deformation band. That wasn't a SWFE really...but you get what I mean.

I think weenies are setting the bar high because there were a few points about how it could be an awesome period. We just don't know if we'll be in the good side of the gradient. 200 miles may mean the difference between epic stretch and epic fail...how are you going to figure that out 2+ weeks out? You can't, other than note the similarities of previous patterns.

On that note, the daily roller coaster continues. Ensembles looked better.

Right...agreed, and that was my point. Boston's epic Decembers were almost all in patterns that someone would look at and say "meh". There's no way most people would look at those H5 patterns and say "man, Boston must have gotten smoked!!". Its probably why HM was saying New England could do well...that sort of gradient look, perhaps some help from the NAO, perhaps not...you can't write it in stone, but those patterns were one's that could deliver some very big snows here. Esp in December when you look back. But its very difficult to say 2-3 weeks out how those patterns will turn out. If the cold stays a little too far north, then we are screwed...if its a little south and we ride the knife's edge, then its a lot of fun and a lot of snow.

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Isotherm

Isotherm

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I had a list of reasons why December could blow torch or why it could turn into a La Nina-gradient pattern / SE ridge in some other long-winded thread that I don't feel like searching for right now. But, there were more reasons than Tropical Forcing / AAM.

I don't think the OLR placement is good though and the stagnant forcing will allow for a semi-permanent Hadley Cell in W PAC and strengthened westerlies with East-Asian Jet. This isn't last year's setup by any means but it will aid in the -PDO type circulation to be enhanced for a while.

Finally, there is more to the Tropics than predicting an octant surge of the MJO. It wasn't that simple for December's possible outcomes, other than the beginning of the month.

Agree the OLR isn't ideal. I think we'll be dealing w/ the -PDO circulation for the whole winter, battling a -PNA signal overall. However the -EPO ridging up in AK/Arctic should keep plentiful cold on our side of the globe for the month of the December, so when the mechanism is there for delivery, I believe we'll be dealing w/ more arctic air. For the first half of the month those bitter airmasses look to remain confined to the nern tier/Canada, until (if) we can improve the NAO signalling.

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HM

HM

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Right...agreed, and that was my point. Boston's epic Decembers were almost all in patterns that someone would look at and say "meh". There's no way most people would look at those H5 patterns and say "man, Boston must have gotten smoked!!". Its probably why HM was saying New England could do well...that sort of gradient look, perhaps some help from the NAO, perhaps not...you can't write it in stone, but those patterns were one's that could deliver some very big snows here. Esp in December when you look back. But its very difficult to say 2-3 weeks out how those patterns will turn out. If the cold stays a little too far north, then we are screwed...if its a little south and we ride the knife's edge, then its a lot of fun and a lot of snow.

You and a few others have been putting out some quality posts in this thread (the last one you did was spot on). There is no way I can say December is snowless for New England with that N PAC pattern in place when historically it has delivered in the past. If we suddenly develop an epic +EPO / Alaskan Vortex, I'll surrender.

Living through the winters of the 1980s and 1990s probably makes us more subdued.

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HM

HM

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Agree the OLR isn't ideal. I think we'll be dealing w/ the -PDO circulation for the whole winter, battling a -PNA signal overall. However the -EPO ridging up in AK/Arctic should keep plentiful cold on our side of the globe for the month of the December, so when the mechanism is there for delivery, I believe we'll be dealing w/ more arctic air. For the first half of the month those bitter airmasses look to remain confined to the nern tier/Canada, until (if) we can improve the NAO signalling.

Certainly but I don't want you to make a mistake that "now we are dealing with the warmth so Christmas will possibly bring cold" due to the changing MJO signal. The MJO could very well stay low frequency with IO forcing and W. PAC forcing, keeping that type of effect going on the flow through early January.

Could this mean a cold / gradient flow for New England / Midwest with a SE ridge? Yes. But the NAO is going to take some time now due to the reasons I stated earlier today.

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CoastalWx

CoastalWx

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Right...agreed, and that was my point. Boston's epic Decembers were almost all in patterns that someone would look at and say "meh". There's no way most people would look at those H5 patterns and say "man, Boston must have gotten smoked!!". Its probably why HM was saying New England could do well...that sort of gradient look, perhaps some help from the NAO, perhaps not...you can't write it in stone, but those patterns were one's that could deliver some very big snows here. Esp in December when you look back. But its very difficult to say 2-3 weeks out how those patterns will turn out. If the cold stays a little too far north, then we are screwed...if its a little south and we ride the knife's edge, then its a lot of fun and a lot of snow.

But I also meant weenies focusing on the words "awesome period" and ignoring posts about why it may not work out. If there is something that consistently bothers me on this forum...it's the latter.

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ORH_wxman

ORH_wxman

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You and a few others have been putting out some quality posts in this thread (the last one you did was spot on). There is no way I can say December is snowless for New England with that N PAC pattern in place when historically it has delivered in the past. If we suddenly develop an epic +EPO / Alaskan Vortex, I'll surrender.

Living through the winters of the 1980s and 1990s probably makes us more subdued.

Yeah definitely. We also didn't experience some of those typical Nina N PAC patterns during that time either like in the 1970s/1960s. We sort of got abruptly introduced to the cold Nina pattern in December 2007 (the previous intro to deep -PDO was an awful pattern for cold in '98-'99, '99-'00) and have had a few winters here where we see the power of the negative EPO/WPO even if the NAO doesn't cooperate. We've all learned they aren't easy to forecast in that setup. SE ridge, +NAO and -PNA fighting the -EPO in the eastern half of the U.S. Total chaos on models.

I think the lack of defined roles in the tropical pacific right now is making it even worse. We see these swings in the Euro ensembles now. Might as well nickname it the 12z-00z Shuffle. 00z comes in terrible and 12z comes in much better the last few days, lol.

At any rate, I think it will be fun to track the outcome of this pattern over the next 3-4 weeks. It will be a good learning experience.

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HM

HM

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Good stuff, and another similarity to last season's -AO period in late jan/early Feb when the same thing happened with the pv displacing towards Greenland. I dont think this is a bad thing to see in the stratosphere during november and dec though, in terms of setting up Jan/Feb. Skiervermont a while back posted the -AO January correlation composite for the lower stratosphere where ideally you want warm anomalies in asia (ie from an SAI signal) with colder anomalies on the atlantic side with the pv displaced there.

December has had a ton of mixed signals going into it like you and many others have mentioned in recent weeks. At times things have looked pretty damn good to me and I got overly optimistic...and other times, like now, it just has not looked great at all. Nothing is written in stone yet with december and im not ready to completely punt it, but regardless of how it turns out, i remain more excited for the jan-feb period.

Thanks man. Yes, January and February are still very game on at this point for the potential of a vortex breakdown. The SAI / warming stratosphere (although vortex wasnt. remember i said 11-12' was just itching to come back from the top haha) and wave 2 response all made us jump (throw in -QBO) on a possible -NAO in early Dec and that was wrong...whatever. This has been an awesome learning experience, perhaps better than last year, in terms of the stratosphere. The waves being amplified is 1 key but the timing seems to be also very important, considering the models today, which is something you don't read a lot about in research papers (in this fashion).

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OSUmetstud

OSUmetstud

Posted
Posted

A few posts about cancelling December requires some discussion on perception of the pattern going forward. It happens every year at this time.

well, I think it is correct that the tone about going forward has certainly changed for the worse during this past week. That's why sometimes I question it's even worth it. Some of you guys are good, but there's some much we don't know that a well reasoned forecast can turn to **** seemingly at the drop of a hat.

I don't like to hear about "chances" in two weeks. It's the winter for god's sake lol. Of course they're will be chances. you can't just compare everything to last winter and say well it's not last winter...that's certainly true...but not last winter can still be kinda crappy.

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HM

HM

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I believe if the vortex is still sitting south of alaska I think the whole east coast is up s***'s creek without a paddle!!!

lol that idiom when you imagine it literally is pretty funny.

well, I think it is correct that the tone about going forward has certainly changed for the worse during this past week. That's why sometimes I question it's even worth it. Some of you guys are good, but there's some much we don't know that a well reasoned forecast can turn to **** seemingly at the drop of a hat.

I don't like to hear about "chances" in two weeks. It's the winter for god's sake lol. Of course they're will be chances. you can't just compare everything to last winter and say well it's not last winter...that's certainly true...but not last winter can still be kinda crappy.

Look, I take the blame here for long range "chances" but the reality is that when the signals come together, you can possibly reason a period for when a deep amplification with snowfall is possible. Does this mean you can predict snizzle, light overrunning or a localized event? No... but I think there is something to this which I've tried to demonstrate over the years. The "comparison to last winter" point you made is very true, which pertains to the Mid Atlantic idea in December nicely. Different pattern...same sh-t.

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CoastalWx

CoastalWx

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well, I think it is correct that the tone about going forward has certainly changed for the worse during this past week. That's why sometimes I question it's even worth it. Some of you guys are good, but there's some much we don't know that a well reasoned forecast can turn to **** seemingly at the drop of a hat.

I don't like to hear about "chances" in two weeks. It's the winter for god's sake lol. Of course they're will be chances. you can't just compare everything to last winter and say well it's not last winter...that's certainly true...but not last winter can still be kinda crappy.

I think most of us just discuss the pros and cons. Sure the first week didn't work out as planned....I personally thought it would be better. This current break we are in is well modeled...for the last 10 days now. I figured the 10th would probably be when things changed around for a better looking pattern for snow. Maybe give or take a day. Long range as Gibbs used to say can be Voodoo.

But I think most of us have done a good job going over the pros and cons of the pattern. It's a weather forum so I don't know what else we can do.

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Brian5671

Brian5671

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I think most of us just discuss the pros and cons. Sure the first week didn't work out as planned....I personally thought it would be better. This current break we are in is well modeled...for the last 10 days now. I figured the 10th would probably be when things changed around for a better looking pattern for snow. Maybe give or take a day. Long range as Gibbs used to say can be Voodoo.

But I think most of us have done a good job going over the pros and cons of the pattern. It's a weather forum so I don't know what else we can do.

and the red taggers here do a damn good job of it...thank you

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weathafella

weathafella

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Here's the deal. We're in a gradient pattern. If the PNA flexes just a bit we can cash in. Sometimes it won't happen. Will's recap of 2008 is a great reminder. After a rotten SNE snow season folks were antsy and after the ice storm there wasn't hope for a spell. But alas, we had a 2 foot+ snow blitz through the rest of the month IMBY. The NYE clipper was prolific with daytime heavy snow with great dendrites, temps in the 20s or lower. NYD was COLD! Pattern lifted out and it got warm mid month until we reloaded for a nice period thereafter and into February. BOS had 65 inches of snow from mid December through 3/2. Thereafter, winter quit. But most of us were ok with the result.

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