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I'm also concerned that the SSW/Vortex displacement is altering due to the impacts of open water around the ocean entrances to the Arctic basin.

If true then the interaction from open water Arctic to strat above will only become stronger over time as the new open water reality settles into its pattern.

We use 30 year rolling averages to look at climate and we are only a couple of decades into these changes with our side of the basin being the first region to lose its ice. Now the Pacific side is showing a similar evolution so any 'tweaks' we saw in the polar Strat, impacting the formation of the polar night jet and its positioning?

I'm sure our resident experts will tell us if they are noting any changes in the formation of SSW events or splitting of the vortex via more 'novel' (?) torque events driven by rowdy MJO swings compared to past events taking a more traditional route to bring about a warming/split vortex in the polar strat??

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On 11/01/2019 at 12:56, Glacier Point said:

GFS warming a likely reaction to tropical wave / +EAMT in the extended period. Not sure how receptive the stratosphere will be to this given what's happening right now.

QBO west unlikely to have much impact I think, particularly as it will be weakening in the next 2-3 weeks as the band of equatorial westerlies is pulled poleward in response to the SSW.

I posted similarity with 1986 event to illustrate likely timescales but this one occurring a month earlier, so not a total match up. 1984/5 also running close to a top analogue..

download.thumb.png.31ed7186618bc5b0a246b669e8f94e05.png

Going to be a long old road to spring proper, and this event, as last year, going to provide a solid basis for sub-seasonal and inter-seasonal forecasting.

 

What gone wrong this winter?

It seems at the moment that it's a long old road to winter proper bar the cold snap last week everything else seems to have remained beyond day-10

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3 minutes ago, Summer Sun said:

What gone wrong this winter?

It seems at the moment that it's a long old road to winter proper bar the cold snap last week everything else seems to have remained beyond day-10

With all respect to Glacier Point, it is telling that he has not posted a long range prediction using teleconnection, analogues etc since the 18th January but he has posted since then though. So you get the feeling it's gone awry. 

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23 minutes ago, Weather-history said:

With all respect to Glacier Point, it is telling that he has not posted a long range prediction using teleconnection, analogues etc since the 18th January but he has posted since then though. So you get the feeling it's gone awry. 

Without singling out any poster, there does appear a tendency in some teleconnection based posts to be stated with overreaching authority and certainty which when failing to come to fruition are because of some unforeseen extenuating circumstance (if revisited at all), not that the original assessment was flawed or incorrect. Clearly, certainty of forecasts and teleconnections are always limited.

Edited by Interitus
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1 hour ago, Interitus said:

Without singling out any poster, there does appear a tendency in some teleconnection based posts to be stated with overreaching authority and certainty which when failing to come to fruition are because of some unforeseen extenuating circumstance (if revisited at all), not that the original assessment was flawed or incorrect. Clearly, certainty of forecasts and teleconnections are always limited.

I totally agree with that. Still I can't be put on the black list as I'm already on it

Edited by knocker

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5 hours ago, Interitus said:

Without singling out any poster, there does appear a tendency in some teleconnection based posts to be stated with overreaching authority and certainty which when failing to come to fruition are because of some unforeseen extenuating circumstance (if revisited at all), not that the original assessment was flawed or incorrect. Clearly, certainty of forecasts and teleconnections are always limited.

Isn't that just a posters 'posting style' though?

We are all on a continuous learning curve and , on top of that, the game may be evolving away from past behaviours as we try and 'learn'?

I think we're gonna have to find a blend of learning how such interactions evolve and the sweep of possible outcomes but then blend it with any impacts we might be seeing in the lower Arctic Strat come Autumn/Early winter every year now?

Everything is also , after all , just a 'Forecast' .

We can't take it as a literal readout of what will happen over the next period can we?

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2 hours ago, Gray-Wolf said:

Isn't that just a posters 'posting style' though?

We are all on a continuous learning curve and , on top of that, the game may be evolving away from past behaviours as we try and 'learn'?

I think we're gonna have to find a blend of learning how such interactions evolve and the sweep of possible outcomes but then blend it with any impacts we might be seeing in the lower Arctic Strat come Autumn/Early winter every year now?

Everything is also , after all , just a 'Forecast' .

We can't take it as a literal readout of what will happen over the next period can we?

Yes, it's possibly style to an extent and it's not restricted to teleconnection based posts. But some will not entertain discussion on what is after all a public forum which is conceit bordering on arrogance. And a literal readout of teleconnections are often expected (ignoring the climate change aspect). Some time back, Knocker linked to a Michael Ventrice video in a tweet examining the downstream effects of the MJO and one of the key points he made was it is not a 'black box' (the exact phrase I had intended to use) i.e. propagation through either affecting the jet stream, or by Rossby waves on a great circle isn't a given. This from an advocate and acknowledged expert in the field, and it can be taken as applicable to any other teleconnection one chooses to mention.

Anyway to stay on topic, here is a 3D plot of the vortex defined by relative vorticity from today's GFS 12z analysis of the 1-150hPa levels, coloured by temperature. A fairly coherent structure at higher levels, still more fractured below. Temperatures have recovered in the heart of the vortex with the absence of wave activity allowing radiative cooling such that it has reached daily record minima at 10hPa in the MERRA2 data. Now as mean westerly zonal winds have returned throughout, weak wave activity is returning with a wave 1 warming shown on the Asian side and a tell tale 'hole' in the vorticity over the north pacific representing anticyclonic curvature -

18121000en17.thumb.gif.cf071d59700de967dbd46683b5982167.gif

Edited by Interitus
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3 hours ago, Gray-Wolf said:

We can't take it as a literal readout of what will happen over the next period can we?

The posting style of some posters gives the impression  that they think it is a certainity. When it does not happen they often cite an extenuating circumstance- with the phantom of easterly 2012 it was a sudden uptick in solar actvity.... On another occasion it was because the vortex had displaced, rather than split, despite the overwhelmingly evidence saying it had. I am not trying to disparage others for putting their thoughts out there, and just having go because they they got it wrong, rather it think  it's better to admit when something is a bust and look for the reasons why.

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Just had a look on here after a while not looking. https://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/orthographic=57.04,66.54,216

Showing two warmer areas at 10hpa, one above Iberia and one over N E Siberia, the latter associated with a kink in the PV

I'm not schooled enough to know if these areas are significant or not... 

Screenshot_20190209-211526.png

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There are clearly many background signal/drivers and the balance and weighting we should give to them in different circumstances obviously changes. The exploration of how we balance and weight these various inputs is to be applauded and encouraged but it should be understood that despite theany published and peer reviewed papers this is an exploration still very much in its infancy. In an ideal situation clearly driver A being in amplitude B should create analogue C but clearly it doesn't always happen.  SSW,s we are told should give us wintry conditions in 60/70percent of cases yet  I then read Amy Butler tweeting that only 2 in 13 have when the QBO is westerly as it had become this winter so another relatively seemingly straightforward measure is further complicated.  Our media and even the Met office at times try to simplify this down for public consumption but it is not simple. It is is extremely complicated. Some poo-poo background signal altogether because they are too lazy to really try and understand them others I think treat them almost as gospel even though our knowledge of their interaction and effects on one another are limited. 

That said I am s firm believer that without the study of background signals medium longer range forecasting will not improve.  And one thing is for sure when it come to extended and snowy conditions in the UK.ypu won,t get them without the signals we know something about being favourable.

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I would just like to second Joggs thoughts and so nice to see you post again.

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Whatever your opinion on teleconnections, many on here will be rather more sceptical about predictions of a looming cold spell next winter. However this is a good thing because nobody should take any medium/long range forecast as gospel whatever method is used.

I have enjoyed reading the posts this winter especially from Catacol. I find his posts to be very informative but at the same time easy to understand.

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Thanks for popping your head in Tamara, you're a sight for sore eyes!

Yes, most long range forecasts failed miserably, but if you look back over the last few years they often do at all times of year - it's just that during winter a lot of people (me included) get childishly excited at the prospect of snow and ice days.  We don't get people kicking off to the same degree when thunderstorms fail to materialise, or when it's forecast to be sunny for a week and it turns out cloudy.  People need to get a grip and sometimes have a serious think about what they post and more importantly *how* they word it.

And to the mods - you've really been under it this silly season and you've done a remarkable job keeping the rabble in check.

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I think the mean anomoly charts for this winter when averaged out and indeed broken down will surprise a few ........ the main culprit for the failure of winter for the uk is the disappearance of the W euro trough at the time when we needed it to hang around ..... it’s not the first time this has happened and also, it won’t be the last .

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On 11/02/2019 at 15:57, knocker said:

But the point is that some posters seem to arrogantly assume, once they have pushed the boundaries of this limitation  that their forecast of, say, pressure distribution in the Atlantic and western Europe brooks no argument. The clue often is when a post starts, or includes, statements such as "the models are not picking up the signals" which patently assumes that the posters knows with certainty what the correct signals are

Of course pushing the boundaries is fine and anyone doing so should be applauder but a little humility and a little less dogmatic assumption wouldn't go amiss.

I think the weather this season has taught us that arrogance is close to folly.....so at no stage should anyone assume that a reading of the pattern is bound to be correct. Totally agree.

The issue with NWP models and whether they are "picking up" signals is an interesting one. In the end all that NWP is doing is reading exactly the same patterns and signals as we all are - excepth algorithms within the models do it by complex calculation of the physics. In theory that should make them more accurate than any human interpretation....and at short range noone would deny that I think. We all turn to ECM or UKMO or GFS etc once we get within 120 hours or so. But are the models able to make a better read than humans at longer range? For this I think no. A good example would be The Beast last year: the wave pattern in early Jan gave rise to some comments as to the possible longer term impacts of that pattern on the vortex. Up until late Jan the UKMO maintained a low probability of vortex impacts until the sudden turn around in the models into Feb. But the signal for disruption was picked up by those with a wider perspective from much further out - and they were human, not machine. The UKMet press release in the summer I thought was bizarre - it attempted to paint a picture of models that identified the coming split well in advance....but it was a poor piece of reporting because it ignored the obvious reality of reports issued in Jan - and their own words were fired back at them via copy/paste as soon as that article hit the web. It all went eerily silent after that.

Bottom line, as that shows, is that models up above 120h struggle. Above 192 they struggle a lot. And at 240 they struggle so much that they can get a pattern quite dramatically wrong. Human interpretation struggles no less than this if we are honest BUT I dont think there is any arrogance to an approach that suggests NWP may be under or over reading a particular signal at long range. Teleconnective interpretation is trying to do this. If it comes across as arrogant then that is unfortunate - and this winter may serve to act as an antidote to that. Maybe it is more the result of snow passion being thrown into the mix? Maybe passion for snow creates the veneer of arrogance within a forecast. I may well be guilty of that myself.

We move on. Lots to consider coming out of this winter. Big guns on twitter are already musing - there is and will be a lot to read. I hope it makes us all a bit wiser in the end....because ultimately we all want to be able to build forecast lenses that give some accuracy. And in winter for many that means a desire to see some snow. The fact that we get so little snow in the UK away from high ground means that desire will always be acute. Humans tend to crave that which they dont have......!

Edited by Catacol
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1 hour ago, bluearmy said:

I think the mean anomoly charts for this winter when averaged out and indeed broken down will surprise a few ........ the main culprit for the failure of winter for the uk is the disappearance of the W euro trough at the time when we needed it to hang around ..... it’s not the first time this has happened and also, it won’t be the last .

Agree. Some anomaly images are already showing that we did indeed have a strong positive anomaly over Greenland. Unfortunately we also had one off to the WSW......and that meant no undercut by low heights. This is the starting point of my own investigation into what has happened when time allows. Forecast models got the high lat anomaly correct - but the strength of the sub tropical high deflected all the energy of the atlantic up and over the top...giving much more of a Nina feel to things than the expected Nino background. Why was the sub tropical AH so resilient? We have seen this often in recent years as you say here. Is this an effect of generally rising pressure in the christmas pudding where the ice cap is under extreme stress and the oceans warming? The itch I cant quite scratch in terms of that argument is that relative pressure patterns are what drives surface flow. Does a warming world mean the end of relative pressure variation? Obviously not.....so something else is at the heart of AH resilience and the inability of the NAO to turn negative. Masiello has tweeted this season that he thinks the run of +NAO years is at an end. i'm going to try and pick his brains a bit on that.

Lots to follow up on!

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3 hours ago, Catacol said:

Agree. Some anomaly images are already showing that we did indeed have a strong positive anomaly over Greenland.

I disagree with this.

Just been looking at the actual recorded SLP mean at Ittoqqortoormiit in the S of Greenland. Now during the cold spells of Dec 2009, 2010 the recorded SLP was between 1030-1040mb. The SLP during Dec 2018 was only around 1005-1010mb. During Jan into Feb the SLP has been generally around 1015. At no stage has the SLP ever get above 1020mb at this location for the entire winter. This makes sense to me as I always follow the Iceland GEFS SLP mean and here this has never got above 1020mb.

So whatever the anomalies show, for me we have never seen any form of a GH.

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8 minutes ago, TEITS said:

I disagree with this.

Just been looking at the actual recorded SLP mean at Ittoqqortoormiit in the S of Greenland. Now during the cold spells of Dec 2009, 2010 the recorded SLP was between 1030-1040mb. The SLP during Dec 2018 was only around 1005-1010mb. During Jan into Feb the SLP has been generally around 1015. At no stage has the SLP ever get above 1020mb at this location for the entire winter. This makes sense to me as I always follow the Iceland GEFS SLP mean and here this has never got above 1020mb.

So whatever the anomalies show, for me we have never seen any form of a GH.

Yes, these anomaly charts look good but like you said the average pressure could be say 985mb, an anomaly chart  could show it was +25mb that would only mean it was an average of 1010mb. That's not high pressure, it just means a weaker low pressure.

This is the problem I have with these analogue charts that have been posted in the past. They give years when such pressure anomalies have been similiar along the bottom of the chart and too often I have seen the years given, they have given different weather to the UK. 

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4 hours ago, TEITS said:

I disagree with this.

Just been looking at the actual recorded SLP mean at Ittoqqortoormiit in the S of Greenland. Now during the cold spells of Dec 2009, 2010 the recorded SLP was between 1030-1040mb. The SLP during Dec 2018 was only around 1005-1010mb. During Jan into Feb the SLP has been generally around 1015. At no stage has the SLP ever get above 1020mb at this location for the entire winter. This makes sense to me as I always follow the Iceland GEFS SLP mean and here this has never got above 1020mb.

So whatever the anomalies show, for me we have never seen any form of a GH.

 

4 hours ago, Weather-history said:

Yes, these anomaly charts look good but like you said the average pressure could be say 985mb, an anomaly chart  could show it was +25mb that would only mean it was an average of 1010mb. That's not high pressure, it just means a weaker low pressure.

This is the problem I have with these analogue charts that have been posted in the past. They give years when such pressure anomalies have been similiar along the bottom of the chart and too often I have seen the years given, they have given different weather to the UK. 

I would assume we would be looking at 500 hpa height anoms  on the long range stuff rather than slp. Heights are always a little more difficult to analyse and therein lies even more difficulties .......

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