Part II, Thanksgiving week transient cold shot and the pattern beyond

[Typhoon Tip]

Here is the link to the previous discusion.

http://www.americanw...pattern-beyond/

I have been a proponent of the WPO/NPO correlation to the downstream pattern (eddy forcing and R-wave discussion topic) for some time. Unfortunately, the CDC, the one source that I know of that computes the daily West Pacific teleconnector (that I know of,) has not updated their data since the 17th of the month. Up until about 2 days, the WPO/NPO had been rather stuck in the AB phase, for about the last 2 to 3 weeks really. This has promoted the vortex near Alaska, which as others have opined to the point of ad nauseam ( ), this is anti correlated to weather patterns of people's dreams.

Quick digression on that: I would like to point out, that should not be considered absolute. While those pointing this our are certainly correct in that it is not helping the realization of the winter weather enthusiast's hopes and aspirations, it doesn't have to mean the end of the game, either. There are a few examples in the Kocin/Uccellini research that showed +PNA, perhaps transient in nature, rolling out underneath the AB phase of the north Pacific Basin, with cold action on the east coast. It's simply a matter of being less favored. Thankfully for your cause, you may not have to wait much longer for the arrival of a more favorable regime.

1) The West Pacific is changing it would appear. http://www.ssd.noaa..../flash-avn.html , shows a massive CAA event taking place over Japan and adjacent areas. In fact, the northern areas of the archipelago have very recently become snow covered, as Siberian air has been advecting actively across the Japan Sea - long fetch oceanic-effect snow. This type of fluidity in the pattern is typical of the negative phase of the WPO. The WPO and the EPO have a robust positive correlation; when one is negative, the other tends to be negative better than 50% of the time (considering the normal precession of events in the atmosphere, it would seem logical to assume at least some time-lag should be applied). This deep layer CAA across the expanse of the NW Pacific is a new event, one that very well could signal an on-going R-wave change rippling downstream across the Pacific Basin. The EPO has a stochastic variability, somewhat less so than the NAO by my experience, but a variability nonetheless. I wish I could see a daily EOF of that domain, but I would argue that it would probably either show a more active decent in mode change, or that one is nearing, based on all these large scale observations.

2) I also want to add ( as we have discussed in the recent past) that massive cryospheric recovery this year. There is a lot in the way of "cold momentum" going on in the atmosphere, where despite the +EPO/+NAO, temperatures have been colder relative to those indexes. I am not sure why that is, or what physical processes are causing that to happen, but it is the cards we are dealt with. I feel pretty strongly that ANY tendency to back the deep layer flow NW through the heart of the Canadian shield, will probably realizes more cold in the GL-NE, and upper MA regions than would normally be the case comparing to EPO/NAO modes.

3) The overnight Euro ensemble mean may be latching onto said changes in the Pacific. We may not be seeing a hugely expressed +PNA per the overnight means, but raising heights en mass betwee Hawaii and the West Coast of N/A the way it did certainly takes strides toward acknowledging -WPO. Related to this, the MJO was weak to perhaps lower moderate in magnitude as it passed through Phase 8 and entered 1 on the Wheeler diagram over the past week to 10 days: http://cawcr.gov.au/...ast90days.html.

The magnitude of the wave is important for establishing forcing on the pattern, no doubt, but I believe it's feedback ability becomes enhanced when the more polarward (WPO) correlates. a -WPO with a late Phase 7 through 1.5 MJO is a constructive wave interference on the large scale. I've also noted in the past that there is (obviously) a disconnect between the WPO and MJO - this is not an attempt to say their is a dependency there at all. It is a matter of two disparate forcing either coming in or out of phase with one another. From that same logic, the +WPO and MJO is a deconstructive wave interference regime, and in this latter circumstance the MJO at relative magnitudes would be less effective.

Putting these 3 discussion concepts in a blender ... it pours a tastier beverage than what the enthusiasts have been imbibing over recent times. Obviously the Euro's operational version was impressive with cold loading into the 50th parallel, and even somewhat farther S from D7-10. My suggestion would be take that with the usual degree of caution given the time range, but would also conclude for the time being that the large scale circulation appears headed that way more than less, so certainly something to look for. Don't be shocked, also, if the signal drops in an operational run or two, particularly as the GFS's poorer initialization schemes fumble around with the pattern change for while.

[Tropopause_Fold]

nice write-up, John.

Hopefully we can see things starting to move around as we turn the calendar to December.

[CoastalWx]

Good disco John. At least there are some signs of change...of which you laid out in the discussion. I think we certainly can have the door open for some snow events with the PNA going +...it just seems like we are doing a yo-yo deal in the beginning of December, and I could see more mild periods too. I think any help from the NAO domain is gone for now, so we'll need the Pacific to throw us a bone.

[QVectorman]

Nice write up as usual. Do you have any thoughts on the idea that the MJO is in the same phase as last month at this time (but to a lesser degree amplitude wise) along with similar N/AO and PNA indices and thoughts on the storm for thxgiving wkend? Where can I find the PNAP numbers to make a comparison?

[Typhoon Tip]

Good disco John. At least there are some signs of change...of which you laid out in the discussion. I think we certainly can have the door open for some snow events with the PNA going +...it just seems like we are doing a yo-yo deal in the beginning of December, and I could see more mild periods too. I think any help from the NAO domain is gone for now, so we'll need the Pacific to throw us a bone.

The "yo yo" - ing is annoying, no doubt. But determinism as we all know is a commodity during times of change, to which this is the first evidence that's been clad enough to really consider - and you are right, it's all PNA --> PNAP related...

Again, I like the fact that the snow covers all of Canada at this point - for all intents and purposes. Every day a spend a minute looking at sfc obs, satellite... etc... There's cold available to us; though it is hard at times to imaging that on a 52F day with light winds. Man, it's gorgeous out there though!! If the operational Euro's blend with it's own 0z mean comes to fruition, that cold will drill in I suspect.

[#NoPoles]

however you want to explain this pattern...it is abnormal and it is messing with the long established natural rhythms of some of the plants around here...my honeysuckle and forsythia bushes are currently flowering...their natural flowering cycle should be in June and April...

[Ottawa Blizzard]

The "yo yo" - ing is annoying, no doubt. But determinism as we all know is a commodity during times of change, to witch this is the first evidence that's been clad enough to really consider - and you are right, it's all PNA --> PNAP related...

Again, I like the fact that the snow covers all of Canada at this point - for all intents and purposes. Every day a spend a minute looking at sfc obs, satellite... etc... There's cold available to us; though it is hard at times to imaging that on a 52F day with light winds. Man, it's gorgeous out there though!! If the operational Euro's blend with it's own 0z mean comes to fruition, that cold will drill in I suspect.

what do you think of henry Margusity's musings today? Accuweather will be updating their winter forecast come December 1

http://www.accuweather.com/en/weather-blogs/meteomadness/why-so-warm-in-the-east-severe-wx-and-snow-in-the-forecast/58066

[Typhoon Tip]

Nice write up as usual. Do you have any thoughts on the idea that the MJO is in the same phase as last month at this time (but to a lesser degree amplitude wise) along with similar N/AO and PNA indices and thoughts on the storm for thxgiving wkend? Where can I find the PNAP numbers to make a comparison?

Actually I do, and almost included it in that, but felt is was getting long and didn't want to glaze over any eyes.

The MJO is doing, so far, something similar to what it did last year from November into December; and we'll see if it does so again heading through the next cycle. The weight of it's magnitude has been on left side of the Wheeler diagram. It's a fascinating question as to why, but that aside ... that would tend to oppose the -PNA. I am, honestly, unsure how to really use the correlation table at CDC for MJO's correlation to the PNA, because PNA is a spatial domain, and the MJO is a scalar value of discrete phases - their numbers don't make sense unless each phase of the MJO is done individually in my mind. Anyway it is plausible in my mind that the these changes are due to the MJO to some degree. The inclusion of the -WPO in that is my own hypothesis open to debate/science.

I like that idea though - a lot.

As far as the PNAP, it is important to remember that is a verbal distinction, one that I've used in the past to delineate the spatial variation between the PNA a whole, versus just the N/A aspect of the PNA's domain. The PNA is suck a massive spatial domain that it is possible the N/A aspect of it falls away from the mode when analyzed in quadrature. And I think that is important, because a rising or falling PNA, may or may not be better reflected in the flow over N/A. It is why I have often tried to explain that a -1SD PNA isn't a bad thing if you've just come from -3.5 SD across a single week to 10 days. That means a huge amount of atmospheric mass is on the move.

John

[Typhoon Tip]

however you want to explain this pattern...it is abnormal and it is messing with the long established natural rhythms of some of the plants around here...my honeysuckle and forsythia bushes are currently flowering...their natural flowering cycle should be in June and April...

My Lilac has decided to sprout new green leaves - yeah. Rumor has it Cherry Blossoms were seen around Boston.

I was fiddling around with the notion that that cold wave and snow in late October followed by balm may have duped some of the vegetation into thinking winter had come and past - lol. I am not botanist/biologist, so I am less certain how plant life triggers growth response - if based on temperature trends.

[HoarfrostHubb]

My Lilac has decided to sprout new green leaves - yeah. Rumor has it Cherry Blossoms were seen around Boston.

I was fiddling around with the notion that that cold wave and snow in late October followed by balm may have duped some of the vegetation into thinking winter had come and past - lol. I am not botanist/biologist, so I am less certain how plant life triggers growth response - if based on temperature trends.

I had to mow yesterday. A few weeks ago I had 20"+ otg lol

[Clinch Leatherwood]

http://www.accuweather.com/en/weather-blogs/meteomadness/why-so-warm-in-the-east-severe-wx-and-snow-in-the-forecast/58066

HM and DT among others I think are warming up the fat lady.

He's using the SOI to possibly indicate the cold isn't going to establish itself this winter.

[#NoPoles]

My Lilac has decided to sprout new green leaves - yeah. Rumor has it Cherry Blossoms were seen around Boston.

I was fiddling around with the notion that that cold wave and snow in late October followed by balm may have duped some of the vegetation into thinking winter had come and past - lol. I am not botanist/biologist, so I am less certain how plant life triggers growth response - if based on temperature trends.

actually, give yourself some credit plants evolved closely with climate/dominant weather patterns in terms of reproduction and survival...

[OSUmetstud]

HM is definitely not warming up the fat lady...read his post in the negative NAO thread over the last couple days.

I thought September's 50mb QBO number was peak but the October number is now peak and quite amazing:

2011 6.00 6.02 6.31 6.25 8.24 9.30 9.35 9.06 10.00 11.46

Here are the latest solar flux values:

2011 834 946 1158 1125 958 958 941 1017 1345 1372

And the ap index

2011 6 6 8 9 9 8 8 7 12 7

The state of the stratosphere is very much acting like the research of HT currently with a very cold stratospheric vortex / +AO. The temperatures are coldest in the lower levels

(50-70mb) while 30-10mb is a bit warmer.

We need to get beyond this recent flare-up in solar activity before we can get back to a more conducive blocking pattern (+QBO / higher solar correlations won't work this

winter and especially in early winter):

Interestingly, the MJO has had a speed that has at the very least surprised me. Someone pull the plug on it already! A phase 7-8-1 response in mid-November is not a good

thing for cold lovers, esp. during a cold ENSO. This time of year becomes very tricky assessing how the MJO will affect circulation since the overall jet stream is in the

process of going into "winter mode." Anyway, this autumn, the EPO goes positive during +AAM tendencies/global mountain torques. These periods have had a weakened

Aleutian High. It may not be a bad thing getting the forcing back into phase 2-5 to allow the Aleutian High to rebuild.

One possibiliy is that we are heading for a relative max in the AAM in December or even early January and this may keep the MJO moving quickly. While ENSO is saying, "get

back to where you belong," the state of the stratosphere is saying just the opposite. These conflicting factors may be why the MJO is doing what it is doing but this is only a

hunch. This will pay off down the road because the same factors causing the warmth now will become favorable for split flow / +PNA/-NAO.

Interestingly, there are some decent similarities to 1999-2000 and 1975-76.

-Both had lower stratospheric winds over the equator that were positive (50-100mb)

-Both were second/third year La Niña events

-Both had a similar pattern to the Nov and predicted Dec MJO forcing with 1975 being a better match

2011 has a stronger +QBO and weaker solar/geomagnetic state than both years. It is also weaker with La Niña, too.

Apym 1999 10 12 14 12 8 7 10 15 19 19 14 10 12.5

Apym 2000 13 16 9 15 15 15 21 16 18 18 17 7 15.0

Apym 1975 16 18 20 16 13 11 12 10 10 12 18 12 13.9

Apym 1976 13 17 23 17 14 10 9 9 13 12 9 10 12.9

Apym 2010 3 5 5 10 8 7 5 8 5 6 5 4 0.0

Apym 2011 6 6 8 9 9 8 8 7 12 7 . . 0.0

I suspect when solar activity drops in January, like it did in 2000, the NAO / AO will be extremely negative for a time. In terms of December, both 1975 and 1999 had a decent

-NAO develop 12/15-20. They significantly diverge in general circulation for the CONUS in early December, however. This is a very noisy time as we transition to winter and

there are a wide range of possibilities for 2011.

While ending November on a warm note seems like a given, the North Pacific will be in the process of retrograding. This may give rise to the PNA in early December. So while

a full blown Arctic Attack may not be in the cards, a general PNA pattern is very possible as the overall N PAC continues to retrograde. Perhaps this ends up being brief as the

MJO continues to send us "bad signals" through mid-December. Maybe the SE ridge returns for a while before the development of a -NAO takes the heights down.

The idea of a SSW this January has been something I have liked for a while now. All the years with a setup similar to 2011-12 had a substantial SSW/MMW and some of my favorite years had it in January. It is quite possible that a majority of January and February come in cooler than normal across the eastern US, but it depends on how fast this all occurs.

Some of you are arguing for a late January response, which is perfectly reasonable. However, if the MJO continues to remain faster than normal, you are going to get a tropical boost much sooner than that in the month, possibly jump-starting the SSW.

Whenever this period occurs, it will have significant cold / snow and be similar to the last couple of years' outcomes in terms of wintry extremes. The potential exists for historic snow / cold with this particular round of -AO and the timing of it couldn't be better (or worse) for significant cold.

[40/70 Benchmark]

http://www.accuweath...-forecast/58066

HM and DT among others I think are warming up the fat lady.

He's using the SOI to possibly indicate the cold isn't going to establish itself this winter.

Please don't insult our own "HM" by referring to that bastion of meteorlogical irresponsibility as HM.

Furthermore, who in their right mind gives a flying front what he thinks......DT is implying that it may take most of Dec to change the pattern...tell us something we don't already know; this on the heels of his orgasmically robust winter outlook.

-Excuse me for not joining the masses in lining the Tobin.

[CoastalWx]

I could see a -NAO in January...at least I hope that there is one. I'm also hoping via a SSW or just that fact that we haven't had a back half of winter for a long time....Feb and March are actually good around these parts.

[40/70 Benchmark]

HM is definitely not warming up the fat lady...read his post in the negative NAO thread over the last couple days.

DT and the real HM are essentially on the same page....he is referring to the Accudolt.

[OSUmetstud]

what the heck is a SSW? I forgot the acronym.

Stratospheric warming?

[CoastalWx]

what the heck is a SSW? I forgot the acronym.

Stratospheric warming?

Yeah, Sudden Stratospheric Warming.

[Baroclinic Zone]

Yeah, Sudden Stratospheric Warming.

Would this be what we would/may need to weaken that AK vortex?

[Damage In Tolland]

http://www.accuweath...-forecast/58066

HM and DT among others I think are warming up the fat lady.

He's using the SOI to possibly indicate the cold isn't going to establish itself this winter.

LOL..Margusity is the biggest idiot in the wx business. An absolute joke to the science.

HM on the boards is one of the most skilled mets in the world.

And who cares what DT thinks..In his winter forecast he had a brutally cold December for the east

He has no clue

[Ji]

JB just good a Kevin Woody from the Euro

[CoastalWx]

Would this be what we would/may need to weaken that AK vortex?

It would do that, and also help with blocking...both perhaps with the EPO and NAO.

The vortex can also weaken from a bottom up approach. In other words, MJO driven convection helping to raise heights in that area. SSW would be a top down approach.

[OSUmetstud]

OP Euro actually has positive anomalies over the entire state of AK...with negative anomalies over the Kamchetka. -EPO might be trying to develop at the end of the run.

[Baroclinic Zone]

It would do that, and also help with blocking...both perhaps with the EPO and NAO.

The vortex can also weaken from a bottom up approach. In other words, MJO driven convection helping to raise heights in that area. SSW would be a top down approach.

Thanks. I learned sumthin' new today.

[scoob40]

A brief summation of Pastelok's thoughts regarding less certainty on any meaningful flip to cold in December for us

" Looking at the European week three height anomalies, there is a look of a positive AO and positive NAO with a strong upper vortex around the Pole and some ridging off the West Coast, and also in the Southeast. But heading into week four, the vortex near the Pole looks weaker. The Southeast ridge flattens and stretches back toward the southern Plains. More ridge shows up again north of Hawaii, forcing the upper trough in northwestern Canada to sink southward. This means cold may shift back into the Northwest and warmth into the southern Plains. If this is correct, then what happens in the early part of December may not be considered a flip in the pattern, but another brief change that reverts back to the same old pattern that we see occurring presently for mid-December. I want to see more support before pulling the trigger on the cold idea in the Midwest and East. I am not getting that from the European weeklies. With the lack of snowfall and blocking, it may be difficult to see well-below-normal temperatures anywhere from the Plains on east for a while. "

[CoastalWx]

Thanks. I learned sumthin' new today.

Gibbs, HM, Wes etc are pretty good explaining that stuff. My strength has always been medium range...but those aspects of meteorology are frontier stuff. Lots of theories out there, but is an area where I'm trying to get more familiar with. Some of the solar stuff seems like a reach imo, but again...I'm no expert.

[weathafella]

Scott....OP Euro appears to "kick" that bad azz PV into Kamchatka after all!

[Typhoon Tip]

Would this be what we would/may need to weaken that AK vortex?

I wouldn't hurt... A Sudden Stratospheric Warming event: They originate in the higher altitudes of the stratosphere within the domain of the polar vortex. The key to whether the eruption of a warming in those very high altitudes is whether or not the anomaly begins to propagate downward in altitude.

If so, the warm lobe begins to penetrate the tropopausal depths, causing large scale static stability. This limitation of rising air leads to a middle and upper level geopotential eruption, and the core of the vortex "fills" - blocking emerges at high latitudes.

That model tends to correlate against the presence of the Alaskan and Davis Straight PVs, replacing those regions with positive height anomalies. What this also means is that the main band of the westerlies ring around the NH rosey is suppressed in latitude overall - often in Meteorological parlance this is referred to as "pancaking the polar vortex" et al.

This opens the flood gates and pours cold into the middle latitudes. I began post this correlation of SSW to blocking my self back when this was Eastern ...circa 2005. I'll dig around and see if I can find some of that annotated material.

As far as where the SSWs come from (how), I have heard everything from planetary wave decay at high latitudes (basically the termini of WAA patterns at high altitudes), to interactions with the polarity of the solar wind. One thing I have always found interesting is that the mass of the warming event when it first is introduced to the medium is hugely LESS than the mass of the anomaly once it reaches the much denser 150mb sigma level of the mean tropopause. It's like .5mb where the heating anomaly emerges, yet that is enough to heat an ~ 149.5mb mass differential? Something is continuously injecting heat into the medium as the warm anomaly progates downward in altitude.

[Typhoon Tip]

OP Euro actually has positive anomalies over the entire state of AK...with negative anomalies over the Kamchetka. -EPO might be trying to develop at the end of the run.

I'm wondering as much - yes. This is definitely what the discussion is attempting to address - that possibility, and why.

[CoastalWx]

Scott....OP Euro appears to "kick" that bad azz PV into Kamchatka after all!

I reserve comments until the ensembles.