Pattern Changing: Early December threats?

[CoastalWx]

The NAO block is actually south and southwest of a classic look for a -NAO....its creating quite a road block very close by.

The setup is extremely chaotic and quite blockier than you typically see in a strong Nina. Though we've pointed out, in the past, we've seen some blocks develop in a mod/strong Nina...just not in recent times through the +PDO phase of a decadal cycle.

And I'll say it again....we don't need a positive PNA to get a snow event in here.

Sure, a +PNA is great for getting I-95 KU events, but we aren't exactly being choosy here, nor (from a greedy standpoint) do we really care if it snows or not south of here. My favorite storm of all time had a monster -PNA....the December 1992 monster.

I didn't mean that either, I was just saying it throws another curveball as to how..if at all, east coast cyclogenesis happens.

[CoastalWx]

The NAO block is actually south and southwest of a classic look for a -NAO....its creating quite a road block very close by.

The setup is extremely chaotic and quite blockier than you typically see in a strong Nina. Though we've pointed out, in the past, we've seen some blocks develop in a mod/strong Nina...just not in recent times through the +PDO phase of a decadal cycle.

And I'll say it again....we don't need a positive PNA to get a snow event in here.

Sure, a +PNA is great for getting I-95 KU events, but we aren't exactly being choosy here, nor (from a greedy standpoint) do we really care if it snows or not south of here. My favorite storm of all time had a monster -PNA....the December 1992 monster.

I actually rather have the nao not so west based, so I don't mind the position AS OF NOW. There has been an ever so slight adjustment to the east of the last 4 days, but very slight.

[snowNH]

I say everybody takes a few days off of model watching. Sit back, wait, and the snow will come.

[ORH_wxman]

I didn't mean that either, I was just saying it throws another curveball as to how..if at all, east coast cyclogenesis happens.

Well I wasn't implying you were obsessing over the PNA...but I've read a few posts that are.

Sure, in a perfect world, we'd have a monster +PNA that connected up with the EPO ridge and a deep trough over the east with a -NAO to give almost zero chance of a lakes cutter and everyone from Richmond to Caribou sees a 12-24" snowstorm....but unfortunately we are not in a perfect world at the moment.

We have to live with what we have.

I feel like I've been preaching to the choir about the current PAC setup. I've seen MUCH MUCH worse patterns for us than this upcoming one. (see the Dec '06-early Jan '07 pattern I posted yesterday and late 90s Nina patterns I posted a couple days ago) We have an active pattern with some cold around and a potential gradient....that will definitely give us some chances. The other patterns gave us no chance at all for the most part. The EPO region is the key.

If the -PNA was really such a bad thing, it must be a miracle of miracles that we got many a great snow event here with a deep PNA trough out west.

[CoastalWx]

Well I wasn't implying you were obsessing over the PNA...but I've read a few posts that are.

Sure, in a perfect world, we'd have a monster +PNA that connected up with the EPO ridge and a deep trough over the east with a -NAO to give almost zero chance of a lakes cutter and everyone from Richmond to Caribou sees a 12-24" snowstorm....but unfortunately we are not in a perfect world at the moment.

We have to live with what we have.

I feel like I've been preaching to the choir about the current PAC setup. I've seen MUCH MUCH worse patterns for us than this upcoming one. (see the Dec '06-early Jan '07 pattern I posted yesterday and late 90s Nina patterns I posted a couple days ago) We have an active pattern with some cold around and a potential gradient....that will definitely give us some chances. The other patterns gave us no chance at all for the most part. The EPO region is the key.

If the -PNA was really such a bad thing, it must be a miracle of miracles that we got many a great snow event here with a deep PNA trough out west.

I think Nate et al are trying to imply that a -pna is a bad thing for this time of the season...meaning early on. The thing is..you know as well as anyone, that nothing is ever black and white when it comes to meteorology. That's the one thing that always bothers me...when people mention things like "well we will see the nao vanish completely because the AAM is negative, which means the Pacific is cooling and the MJO is in phase 3 and this means a monster GOA low". It just doesn't work like that. If that were the case, then the Nina winters that our parents enjoyed would be another '98-'00. Sure the physics of some of these examples would argue their point and I understand that, but we've seen these rules go into the garbage so many times, and the New England region tends to be the area that says "To hell with these assumptions".

[Tropopause_Fold]

Gfs is entertaining.

[Tropopause_Fold]

This may come across as negative but seriously not - this is utterly as objective as I can make it (sparing you my proclivity to be sardonic and dark-witted)

There's a fair chance folks that ALL the models are not handling the NAO out in time. Correct that: There is a 100% chance that the ALL the models are mishandling the NAO status out in time - an error that grows spectacularly from D5 (or so) onward do to inherent uncertainty with modeling at any given time, but particularly now given the following:

First, the NAO has a intraweekly time scale modality at times that behaves with just slightly less than the stochastic nature of the daily synoptic pattern. Granted, once a solid negative or positive departure gets underway there is some "so-so" dependency that it will persist, but unless you have other correlated factors contributing, that depending falls to pieces pretty fast. With the latter lacking, I am growing increasingly (and rationally) suspect of the entire scenario.

1) The -PNA is actually better correlated with the +NAO as the cold season gets stronger. This has to do with the lower R Wave numbers, but that's a different brunch. Anyway that off the bat is a bit less supportive of those blocky solutions of the last 2 days, certainly as to the extent of those bizarrely absurd solutions, and considering the -PNA on-going.

2) There is no tropopausal relay of any thermal anomalies currently propagating out of the polar field stratospheric vortex pointed toward middle altitudes - the total distribution in fact is nearly near 0, but if anything is slightly cooler than normal. At least for the AO that should mean somewhat of an alleviated negative phase state; since the NAO and AO share domain space, there is obviously going to have to be some consideration extended there, too. One encouraging aspect about being close to neutral in the deep layer thermals is that the AO is probably going to be more guided by planetary wave decay - so you go even money odds that it will be negative or elsewhere.

3) Lastly, from an ensemble perspective it is unclear at best what the signal is coming from the GFS regarding the major teleconnectors. We have the two agencies currently pumping out disparate behavior with the NAO. The CPC show it rising almost to neutral - with typical mop ended incoherence by D13 but what does one expect... Meanwhile, the CDC indicates only a modest relaxation from -2 to ~ -1SD. The PNA at NCEP is forecast to rise to +.25 SD, but then slips less than 0, while everyone else says it stays negative for the foreseeable future. I got go with the weight on that one because currently there is just about 0 tropical forcing coming out of the Pacific domain from India clear to California. The MJO has stifled in incoherency and looking at the available OLR products there doesn't seem to be any hope at all for anything to bump the roulette wheel around into a new ending position. With no coherent means to alter a nod to Newtons 1st law would seem apropo.

(As a side not - and check this - I've read that westerly QBO phases are negatively correlated to the AO, and that easterly phases ironically actually have almost no correlation either way. Why that is is probably a fascinating question, but the -QBO has +AO sister as I've understood it. Now, I am certainly not without my history of fantastic displays of dyslexia so if I am flipping these signs around my apologies, besides not a big fan of this QBO thing anyway for it having too many degrees of separation)

All these storm depictions are/were based on numerical instability in the models - perhaps not even real if the blocking ridge verifies weaker and/or displaced further E and S (as it should given these above reasons).

Back to the NAO ... I have noticed that last two cycles of the deterministic ECM and GFS are inching the positive height node across the map ever more S and E - not much more and what do you have? . The 00z ECM actually shows a completely neutralized NAO field above 50 or 55 N nearing D9 - a condition that becomes a bit less directive on the East Coast storm track.

Based on all: It is possible the models have been erroneously over-developing the extent of the positive anomaly, and in doing so were formulating a compensating negative departure that was spatially forced into a position S of NS (by planetary wave numbering). If that is true the whole scenario was based on macro-scale feedback, and would most likely be false. That would explain that appearance of a 5 day polar vortex that for the first time [probably] in recorded history maintains a near blizzard for the entire time. We have collectively said it regarding these "weird" GFS solutions, and sometimes when things appear weird, suspicious...etc, you sense that for a reason - IT IS. Not to back peddle, but that doesn't have mean something special can't happen - as I have said many times in the past, anomalies nested in large scale anomalies happen all the time. You know ... the New England cut-off low events not a-typical to April are just that; if you step back and look at the whole of the domain while one of those is whirling around the waters E of NE, usually there is a huge ridge in position, a nascent +NAO, but a stranded vortex nearby - that's anomaly within an anomaly incarnate. If I am on to something regarding the larger scale direction we are heading over the next 3 weeks, that does not withstand local scale anomalies.

There are other factors to be hopeful for if you are a winter weather enthusiast emanating from the larger global perspective of things. For one, we are still situated in an on-going solar negative. That is measurably shown to mean increased visible light and decreased UV in the total solar budget. That means there is less ability for stratospheric ozone to be broken down by UV, which tends to lead to SWEs. That typically is more for after xmass year to year, but we still have that to assist the later winter. Perhaps more prevalent is the cryosphere. It is pretty impressive and we are not seeing any issues with expanding the areal coverage of the land snow and sea ice heading through the autumn and continuing as we open the door to the Meteorological winter. So impressive is this latter factor that I think it would be foolish to close the door on colder solutions entirely...particularly from 40N and Nward. For obvious reason, a pervasive Canadian shield snow pack persisting means that cold is near by, and comparatively less predictable permutations in the flow can easily grab moments of this air and tug it down. This can set stage of overrunning scenarios in the means, but also set up some interesting thermal gradients 'just in case' a wayward S/W spits through the flow in timely fashion (Dec 2005 is really what that was...).

Lol....dear lord.

[Alpha5]

Gfs is entertaining.

Retro bomb pummels NNE again

This is getting comical

[CoastalWx]

Gfs is entertaining.

Just a little. God what a mess to resolve.

[Tropopause_Fold]

Just a little. God what a mess to resolve.

I kinda like where we are headed here.

[ORH_wxman]

I think Nate et al are trying to imply that a -pna is a bad thing for this time of the season...meaning early on. The thing is..you know as well as anyone, that nothing is ever black and white when it comes to meteorology. That's the one thing that always bothers me...when people mention things like "well we will see the nao vanish completely because the AAM is negative, which means the Pacific is cooling and the MJO is in phase 3 and this means a monster GOA low". It just doesn't work like that. If that were the case, then the Nina winters that our parents enjoyed would be another '98-'00. Sure the physics of some of these examples would argue their point and I understand that, but we've seen these rules go into the garbage so many times, and the New England region tends to be the area that says "To hell with these assumptions".

Yeah I did mention that the PNA is bigger in November than other months...however, it seems to disintegrate pretty rapidly once we get into December, so the time frame we are talking about in the first ten days of Dec, the PNA becomes less important.

Obviously as you said, its not as simple as "PNA is this, the NAO is this, so this is what the weather will be"...we've seen it too many times. I've tried to go through the scenarios many times, but I don't think any of it is going to do any good until we actually get a snow event in here.

So we'll just sit back and wait at this point.

[Tropopause_Fold]

Yeah I did mention that the PNA is bigger in November than other months...however, it seems to disintegrate pretty rapidly once we get into December, so the time frame we are talking about in the first ten days of Dec, the PNA becomes less important.

Obviously as you said, its not as simple as "PNA is this, the NAO is this, so this is what the weather will be"...we've seen it too many times. I've tried to go through the scenarios many times, but I don't think any of it is going to do any good until we actually get a snow event in here.

So we'll just sit back and wait at this point.

Well atleast we know where everyone stands. We're going to read the same stuff over and over. Me...im just going to keep looking for storm chances.

[Hazey]

I kinda like where we are headed here.

To the funny farm on The GFS merry-go-round?.....weeeeeeeeeeeeeeee!

Still lots and lots to resolve. Only thing I see is there is a decent chance it's going to do "something" on or about that date.

Oh can anyone access the GEM output out to 240hrs? Meteocentre isn't working for me. Not sure if that part of the site is down or what.

Thanks

[ORH_wxman]

Well atleast we know where everyone stands. We're going to read the same stuff over and over. Me...im just going to keep looking for storm chances.

Yeah at this point we are starting to rehash the same points over and over and over...hopefully soon we have something more concrete to track. That Dec 5 system certainly doesn't look like its getting shoved west of us at this point.

[CoastalWx]

Yeah at this point we are starting to rehash the same points over and over and over...hopefully soon we have something more concrete to track. That Dec 5 system certainly does look like its getting shoved west of us at this point.

Are you saying you think it will be a lakes cutter???

[Organizing Low]

To the funny farm on The GFS merry-go-round?.....weeeeeeeeeeeeeeee!

Still lots and lots to resolve. Only thing I see is there is a decent chance it's going to do "something" on or about that date.

Oh can anyone access the GEM output out to 240hrs? Meteocentre isn't working for me. Not sure if that part of the site is down or what.

Thanks

UQAM servers have been seeing some intetruptions (maintenance) since yesterday PM, though i think they are resolved now.....my output is coming through....

btw, i just looked at it....how bout the GEM from december 3rd onwards? everyone who posts in new england or nearby gets hammered a couple times

LOL

[ORH_wxman]

Are you saying you think it will be a lakes cutter???

Lol..I meant to say doesn't...I corrected it.

The primary will actually come in through the lakes, but it gets shoved SE pretty violently by most guidance and then tries to redevelop or phase with that storm in the Atlantic....GFS then retrogrades it. Euro, not so much.

[CoastalWx]

Lol..I meant to say doesn't...I corrected it.

The primary will actually come in through the lakes, but it gets shoved SE pretty violently by most guidance and then tries to redevelop or phase with that storm in the Atlantic....GFS then retrogrades it. Euro, not so much.

LOL, ok that's what I figured. Another interesting ensemble run wrt 12/5. Definitely some weenie members trying to hug the coast.

[moneypitmike]

Retro bomb pummels NNE again

This is getting comical

But hasn't it also delayed it so that we're still not any closer in time to hitting as we were yeseterday at this time?

[Ginx snewx]

Well atleast we know where everyone stands. We're going to read the same stuff over and over. Me...im just going to keep looking for storm chances.

This

[Typhoon Tip]

But hasn't it also delayed it so that we're still not any closer in time to hitting as we were yeseterday at this time?

Pretty much -

not any surprise if you read my earlier post.

[Typhoon Tip]

Heh, you know ...if I didn't know any better the 12z GFS ensembles kind of reminds me of the 100 hour storm of lore ... even though as I've outlined I think it's all essentially bull crap for verifiability.

[Typhoon Tip]

I think of all the individual 12z GFS fantasy members P009, right around circa 250 hours, is probably my favorite dream

[Typhoon Tip]

Welp, the next face smack run the Euro should be whackin' on in any minute ...

[Typhoon Tip]

wow, where did everybody go ? ...it's not THAT bad is it

[Tropopause_Fold]

hopefully the euro continues with the nice theme from earlier

[MaineJayhawk]

wow, where did everybody go ? ...it's not THAT bad is it

Just impressed with the consecutive post streak you were on.

Seriously, just waiting to see if the Euro starts showing a retro solution.

[CoastalWx]

Al least we'll have damaging srly winds on Wednesday.

[Tropopause_Fold]

what a soaker that will be for mid-week. perfect set-up to get some heavy rains in W NE

[Typhoon Tip]

Al least we'll have damaging srly winds on Wednesday.

- i wondered when someone would get around to noticing that.