Winter about to mean business folks!

[Typhoon Tip]

Exciting times ahead!

I have peered through the looking glass and has emerged images foreboding rewards and dividends for enduring the almighty westerly-based NAO. Nice to see this which I have not seen in recent years, and that is a linking of major domain spaces from eastern Asia around the globe to eastern N/A - this happened a few times in the mid to late 1970s.

It is hemispheric in scale, and it "may" mean business (sorry about the double quotation mark cop-out, but I gotta do it).

1) Tropical forcing in the Pacific is about as incoherent as I have ever seen it. The MJO wave guide/Wheeler diagrams are showing a completely benign contribution, and without any means to spin the roulette wheel from Japan to California, the -PNA should probably persist. There is monkey-wrench though - the CDC does not concur (below)

2) What is appearing to be the age of the monster polar field invasion [maybe] at hand. It just appears that all anomaly vectors will be controlled by events above 55N until further notice without substantive TF. Those polar teleconnectors being the West Pacific Oscillation, which has a strong correlation on the East Pacific Osciallation, and over the next 10 days to two weeks will be entering a period of rather intense negative SD; this by means of the GFS cluster EOFs derived nightly at CDC. CPC does publish WPO, which would be useful, but since they do not I only have the former to consider

3) As a general overview, here is how this may all play out through Christmas: The WPO relays a mighty negative SD into the EPO - a key link that with very large unionized mass fields implies something dominating. When then applying the typical west to east spacial-temporal requirements (couple days to a week, give or take) that is a higher confidence relay given to the correlation. The positive correlation is there because of Rossby wave numbers and the fact that the atmosphere is always trying to find the most stable spacial layout for long wave troughs and ridges around the hemisphere. Erstwhile, the NAO, which is initially far enough removed from its cousins out west, can and will relax. What does this do? The -EPO this time appears more capable (do to synoptic details regarding placement of features) of creating a trans-Siberian flow across the recovered land-based cryosphere, and now sea ice, into the NW Territories of Canada. The NAO then pulses back strongly negative after 10 days. The relay would complete latching onto this cold air mass, and we wind up with a truer Arctic outbreak between mid month and Christmas.

4) Details: Snow is coming! Firstly, we inject a low-amplitude wave out of the data-sparse region of the east Pacific. I fear this system may be too easily ignored (understandable as focus will naturally want to fall on the Archembault stem-winder event immediately there after) but has potential to do interesting things over next weekend. There is a weak Miller-B transfer scenario signaled there; although the NAO is already entering the relaxation period, I believe the 00z deterministic Euro-type idea of running that up through western/central Ontario is over-doing it, dismantling the NAO influence on the field a bit too zealously quick. Even the hugely biased westerly CMC solution fails the Euro idea, and pops off a 1000mb low leaving Boston Light come next Sunday. D7 is outside the Euro wheelhouse where its verification scores tend to fall off precipitously despite being terrifyingly accurate through D4.5, so I am willing to take the gamble that the NAO willl remain somewhat vestigially influential and keep the storm track more suppressed than the ECM idea. That said, that 'weak Miller-B' is questionable within the blend of the GGEM/GFS thinking. There is a quasi-Norlun appeal there. There is residual jetlet speed maxes running off the Jersey coast latitudes and up under LI or even over head from regardless of any successfully closed off surface circulation in the models. This would mean a compensating surface trough might linger and start the old dendrite production between 850 and 700mb game. Either way, mulit-guidance, mulit-run flagging a polar surface high anchoring N of Maine will mean generalized polar marine transport into a snow profile, which without these more organized definitions tends me to visual grains and flurries amid blue/gray winter chill would characterized the period. Cold air will not be an issue at any time during that time frame, Fri - the following Wed I believe.

The big event: I tipped my hat earlier but that very much appears to be an Archembault stem-winder across now 3 cycles of the GFS, and sits well within the GFS' own ensemble teleconnector spread at the CPC. Unfortunately, the CDC does not agree - I am unsure why the CPC's PNA values are not on the same page with CDC, but where the PNA persist negative at CPC, it spikes to a positive 1SD (almost) at CDC. They derive the values differently: The CDC uses lower tropospheric flux anomalies; the CPC use mid level geopotential anomalies. That question may come down to domain space. But, the CDC values asserts some excitement, the NAO relaxes, the PNA spikes, the flow becomes less compressed over the deep S/SE, and viola! What the GFS did yesterday on the 18z was a brilliant example of dual stream phasing, with PV bifurcation and subsuming of an intermediate, dynamics loaded S/W into a closed bomb near Del Marva. That tasty solution would heave 18"+ from interior VA to Maine notwithstanding the red herring time range of 200 hours at the time. This morning, however, looking at all these mass field teleconnector behaviors, it is not hard to see why the run suddenly opted to generate such a magnificent idea. Moreover, details aside ... the fact that every cycle since has a major EC system, ..including the Euro, it all comes together for better than 50/50 that a large scale event will be there at mid month. I toyed around with this idea a few days ago and I think Scott and I might have shared a post or two about it if memory servers, but at the time it was more NAO-related in that the relaxation was being picked up then - and still is. So it was so-so as a signal. But this appears to be teleconnector convergence, a phrase I coined for when you have initially disparate statistical packages pointing to a similar result at a given location. I like to think of it as the view down the site of rifle scope where it yo-yo in and out of focus, red dots, then kills.

Lots of time, but exciting times ahead. Now, the 12z GFS is coming out any moment. Let's see how continuity - if so - continues, or if immediately it gets lost in an attempt to debase this effort ( ). Even if it does, I would not be shocked if it came back in future runs.

John

[ski MRG]

And there was much rejoicing!!!!! Wahoooo!!! Thanks for the post John, so glad you are back amongst us!!!!

[ORH_wxman]

Nice write up John....here's what I said in the other thread about the Dec 13th threat

After catching up and reviewing more of the guidance from 00z last night, there definitely looks to be a strong signal for a larger system around Dec 13. There's a lot of interesting features, and many of them have the caveat of assuming models are correct with these features....using the Euro ensembles as the safest play, here's what we got:

1. The -NAO block is really an Iceland/UK block coming up for that time frame. This will not have the same suppressing effect as a west based -NAO block in the Davis Straight or Baffin Island. So a north or west trend can come easier in this setup.

2. We actually try and pop a western ridge at this time, so that will offset the more easterly -NAO at least somewhat. It will promote troughing in the east rather and a big SE ridge.

3. Clipper uncertainty before that. The clipper system that approaches the region on Dec 11th will have some sort of impact. Some guidance like the GFS are trying to redevelop it into a quick hitting, late blooming Miller B. A bit of a stronger solution like that would make an inland cutter on the next system less likely. Euro does try to redevelop it too but a bit later and not as impressive. Given that the clipper itself is still in the D5-6 time range, plenty of details to be worked out on that end alone.

End quote.

That said, I still think there is some interest in a possible weak Miller B type setup with the clipper before the larger system potential. The clipper approaches the region on Dec 10-11 and I'm not convinced we don't try and see a bit of redevelopment to the SE of NE or S of LI...something along those lines. Its not uncommon to see that and I've made references to it a few times in the past couple days.

[CoastalWx]

Hey nice post John. It does appear we could be heading into fun times. West based -nao returns with vengeance after whatever happens this weekend, and the ensemble mean has almost a permanent area of low pressure east of sne that oscillates between the waters southeast of Nova Scotia and east of Cape Cod. This likely suggests members have multiple storms at one point or another with s/w timing issues. Indeed you can see that on the e-wall site with ensemble members showing just that. So I would think the chances are there, given the pattern.

[weathafella]

Beautifully written and explained. Glad you're back John!

[hudsonvalley21]

Great write-ups from all. As most said, time will tell. Some interesting times ahead. Welcome back Tip

[Baroclinic Zone]

Great stuff John and Will. You've both spelled out perfectly what we should be looking for with the upcoming pattern.

I'm intrigued by the Clipper as well Will. That system will have implications on any follow up system. The stronger that comes in, the better off we'll be, imo. One other thing to look at/for is where the PV will situate. The Euro and Canadian want to lift that feature out of Hudson Bay whereas the GFS wants to keep a lobe of it penetrating down into it prevent the GFS from running inland.

Just what I am seeing from last nights runs.

[Typhoon Tip]

Nice write up John....here's what I said in the other thread about the Dec 13th threat

After catching up and reviewing more of the guidance from 00z last night, there definitely looks to be a strong signal for a larger system around Dec 13. There's a lot of interesting features, and many of them have the caveat of assuming models are correct with these features....using the Euro ensembles as the safest play, here's what we got:

1. The -NAO block is really an Iceland/UK block coming up for that time frame. This will not have the same suppressing effect as a west based -NAO block in the Davis Straight or Baffin Island. So a north or west trend can come easier in this setup.

2. We actually try and pop a western ridge at this time, so that will offset the more easterly -NAO at least somewhat. It will promote troughing in the east rather and a big SE ridge.

3. Clipper uncertainty before that. The clipper system that approaches the region on Dec 11th will have some sort of impact. Some guidance like the GFS are trying to redevelop it into a quick hitting, late blooming Miller B. A bit of a stronger solution like that would make an inland cutter on the next system less likely. Euro does try to redevelop it too but a bit later and not as impressive. Given that the clipper itself is still in the D5-6 time range, plenty of details to be worked out on that end alone.

End quote.

That said, I still think there is some interest in a possible weak Miller B type setup with the clipper before the larger system potential. The clipper approaches the region on Dec 10-11 and I'm not convinced we don't try and see a bit of redevelopment to the SE of NE or S of LI...something along those lines. Its not uncommon to see that and I've made references to it a few times in the past couple days.

Wow, Will ... you and I were spot on the same page then!! Nice -

Yeah, i really see that Dec 13 deal as being something like "hemispherically" guided into being - so to speak. Basically saying ... there is weighty indicators coming from multiple sources that argue for a major event in that time frame.

Obviously now it will be crowd control to try and mute the over-expectation, preventative suicide watch should storm tracks or other nuances f it up for folks.

[CoastalWx]

That's a weird clipper like feature...almost a sfwe. It tries to pop a secondary all along, but remains progressive. GFS looks nice for interior CT/MA up through ME.

[HoarfrostHubb]

Ears are in the radar position. Ping!

[Typhoon Tip]

That's a weird clipper like feature...almost a sfwe. It tries to pop a secondary all along, but remains progressive. GFS looks nice for interior CT/MA up through ME.

Yes, agreed, I suggest we follow this lead system this week - advisory snowfall could come along with that and the 12z is still banging this hint - as it is also for the 13th fwiw but of course we are going to have morphology issues for days until shorter terms no doubt

[Typhoon Tip]

Holy crap! that's like 2 inches of liquid equiv for eastern sections, with wind going from 20mph to 40mph and crashing heights!

f that is best looking system on a model run since ...i dunno how far back. And, the beauty there is that it could still close off like the former run

[Ginx snewx]

Great AO post on the main page John, nicely done. Scooter and I talked about the AO last night at the GTG, oh this is going to get good.

[Typhoon Tip]

Great AO post on the main page John, nicely done. Scooter and I talked about the AO last night at the GTG, oh this is going to get good.

Hey thanks Ginx - I was beginning to wonder if anyone was aware that was out there. Believe me, that post/thought process was the canvas that this one was painted upon.

Man, you want to shyst your pants?? Take a gander at the 12 hour blizzard on the 12z GFS

[Damage In Tolland]

That's a weird clipper like feature...almost a sfwe. It tries to pop a secondary all along, but remains progressive. GFS looks nice for interior CT/MA up through ME.

I'm feeling it my brotha...feeling it nicely

[Damage In Tolland]

Tippy ..great post.

It's time to cut down the noose from the ceiling, pick up the chair..cover up the rope marks around your neck, put the razorblades away.

Drain the bathtub..put the hair dryer away.

Winter is here and snow is coming in all it's glory

[CoastalWx]

Hey thanks Ginx - I was beginning to wonder if anyone was aware that was out there. Believe me, that post/thought process was the canvas that this one was painted upon.

Man, you want to shyst your pants?? Take a gander at the 12 hour blizzard on the 12z GFS

I'm going to wait and see what happens this winter, but I've heard some interesting tidbits about the AO/Solar etc. from Joe D'Aleo and others. You hit some of those points in previous posts, and I spoke about the NAO behavior during previous Nina's that our parents were fortunate enough to live through. It's certainly an interesting time right now, and sure the NAO may flip in a month or so...but you gotta appreciate the -SD departures that we've been having.

[Typhoon Tip]

Tippy ..great post.

It's time to cut down the noose from the ceiling, pick up the chair..cover up the rope marks around your neck, put the razorblades away.

Drain the bathtub..put the hair dryer away.

Winter is here and snow is coming in all it's glory

Nah, I was never panicked here... Heck it was November - gee wiz. I was hopeful all along that relaxing that NAO ridge might yield better times, and it is a nice lube-up that the deterministic runs are hitting it now.

Hey, Scott, ...Will, do you have the Euro ensembles? I think ECMWF carries the blend now btw -

[Ginx snewx]

Hey thanks Ginx - I was beginning to wonder if anyone was aware that was out there. Believe me, that post/thought process was the canvas that this one was painted upon.

Man, you want to shyst your pants?? Take a gander at the 12 hour blizzard on the 12z GFS

What is exciting to me is the AO continues to bottom out, rebounds then bottoms out, rebounds ETC, keeps us in the goods all winter .

Signal is there for big event, specifics as always.

[Damage In Tolland]

I'm going to wait and see what happens this winter, but I've heard some interesting tidbits about the AO/Solar etc. from Joe D'Aleo and others. You hit some of those points in previous posts, and I spoke about the NAO behavior during previous Nina's that our parents were fortunate enough to live through. It's certainly an interesting time right now, and sure the NAO may flip in a month or so...but you gotta appreciate the -SD departures that we've been having.

FWIW..JB has been hinting the last few days that this winter could actually go the way of 1916-1917..strong Nina that was cold from start to finish basically..due in part to volcanic activity.

Things that make you go hmmmmmmmmm......

[CoastalWx]

Nah, I was never panicked here... Heck it was November - gee wiz. I was hopeful all along that relaxing that NAO ridge might yield better times, and it is a nice lube-up that the deterministic runs are hitting it now.

Hey, Scott, ...Will, do you have the Euro ensembles? I think ECMWF carries the blend now btw -

You can get them now at ecmwf.int up to hr 240. The 00z ensembles brought the second low from near Wilmington DE, very near the BM or perhaps just inside, and then east of Cape Cod.

[Typhoon Tip]

12z GGEM trended significantly more powerful with the that Dec 13'ish system as it relays off the Pac at D6 - ...I dunno, one thing I remember Dr. Colby and I mused one afternoon ...circa 1996, it is always a fool's errand to invest any determinism in outlooks spanning this type of time range, but there are times in this game where it just doesn't seem that way. I know that doesn't sound very scientific; I guess what it really means is that when there is something big in the chaos it tends to have a voice above the din of the plausible solutions - it is like the physics pick up on the big players a bit ahead of the standard verification lead times. This happened in April '97, December '92, March '93...even waaaay back when February '78 - most of these bigger systems had some kind of eerily sensible extended detection in the modeling that kind of transcended the usual cloud of uncertainty.

I guess what I am saying is I have a good feeling about this one

[Typhoon Tip]

You can get them now at ecmwf.int up to hr 240. The 00z ensembles brought the second low from near Wilmington DE, very near the BM or perhaps just inside, and then east of Cape Cod.

Right - okay, good to know. So perfect! wow, 15 members of ECMWF 4-D variable system supremacy signaling perfection at D8-9 ... interesting.

[weathafella]

I have seen the 12Z/5 GFS. It is good. That is all.

[weathafella]

FWIW..JB has been hinting the last few days that this winter could actually go the way of 1916-1917..strong Nina that was cold from start to finish basically..due in part to volcanic activity.

Things that make you go hmmmmmmmmm......

Hi. Although I predicted a 2 week break in January.

[40/70 Benchmark]

12z GGEM trended significantly more powerful with the that Dec 13'ish system as it relays off the Pac at D6 - ...I dunno, one thing I remember Dr. Colby and I mused one afternoon ...circa 1996, it is always a fool's errand to invest any determinism in outlooks spanning this type of time range, but there are times in this game where it just doesn't seem that way. I know that doesn't sound very scientific; I guess what it really means is that when there is something big in the chaos it tends to have a voice above the din of the plausible solutions - it is like the physics pick up on the big players a bit ahead of the standard verification lead times. This happened in April '97, December '92, March '93...even waaaay back when February '78 - most of these bigger systems had some kind of eerily sensible extended detection in the modeling that kind of transcended the usual cloud of uncertainty.

I guess what I am saying is I have a good feeling about this one

I think this sentiment would resonate with everyone, John.....the big ones are preluded by such overwhelming signals, that they are modeled as rather prominent threats among the pantheon of deterministic guidance with a consistency that is pretty uncharacteristic of such extended leads.

[Typhoon Tip]

Man, have you ever more wanted/anticipated a model run like this immediate ensuing 12z Euro - you can cut it with a knife

[dryslot]

Great write up and expert analysis, Looks like some fun times ahead for all of New England..........

[Typhoon Tip]

Quick note on the 12z GFS ensembles - the difference between the 00z dis-chord and the 12z convergence is clearly there. The 12z individual members all have full latitude and/or wave phasing type scenarios for the system that we can for now just call "Dec 13" for clarity. The 00z had much more divergence among the individual runs.

[Typhoon Tip]

Dudes, if we could P002, P006, and P010 into a blender that would make one hell of a tasty drink - epic