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You sound cautiously pessimistic this year Chio - but I'll draw some crumbs of comfort from the suggestion of a weak vortex early on and then a potential SSW later in the season that MIGHT bring more blocking. Enough to make sure that this is the best thread once again of the winter months... and maybe the atlantic cold pool can affect the jet enough to aid in the disruption of the atlantic weathertrain...

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You sound cautiously pessimistic this year Chio - but I'll draw some crumbs of comfort from the suggestion of a weak vortex early on and then a potential SSW later in the season that MIGHT bring more blocking. Enough to make sure that this is the best thread once again of the winter months... and maybe the atlantic cold pool can affect the jet enough to aid in the disruption of the atlantic weathertrain...

I think cautiously pessimistic at this point is a fair assessment. But I am not ruling out any surprises - especially early winter before the vortex cranks up. There are slightly conflicting signals which means that a straightforward El Nino winter forecast is anything but that!

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I think cautiously pessimistic at this point is a fair assessment. But I am not ruling out any surprises - especially early winter before the vortex cranks up. There are slightly conflicting signals which means that a straightforward El Nino winter forecast is anything but that!

 Not providing odds of any nature

 

This is an superb dissection of an atmospheric mode that was within last 7 years non existent. Vortex wins.

 

Any forecasts you see excluding the wintertime variations of the vortex you know will be wrong ( that includes Nino analogs and SSTs). Hint

 

:)

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Hi Chio, first of all many thanks for this wonderfull summary! I will give it some attention to the weather geeks in the Low Countries.

 

Two small things. In the first selection of years (december chart) I noticed 1962. I think you mean 1982?

 

And in Januar 1998 in stead of 1996?

Edited by sebastiaan1973
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http://www.terradaily.com/reports/Forecasters_look_higher_for_clues_to_winter_weather_999.html

 

According to this publication, stratospheric forecasting can double the accuracy of forecasts for 2-4 weeks ahead.

 

 

Fantastic summary there as usual Chiono. I've looked at 500 mb height composites for February under W QBO and a strong El Nino and found a signal for anomalously high pressure west of the UK with a trough over Scandinavia... but no signal for the high latitudes either way, despite that vicious looking 10 mb composite. Delays working down to the troposphere perhaps?.

 

The high heights west of the UK appear to be in large part a consequence of the Pacific jet barreling into the Atlantic from around Florida to The Azores Isles.

 

 

Having said that, there's an interesting progression when looking at 10 mb, 30 mb and 100 mb levels for February. I've used 1958 instead of 2003 (i.e. only strong El Nino + W QBO winters) but the theme is broadly similar:

 

FebStrat_10_30_100mb_GPH.PNG

 

Increasing signs of a ridge over Greenland, but more west-based in terms of the -ve NAO... which is in line with your concerns but could be adding to the strength of positive height anomalies west of the UK at the 500 mb level (which are around +10 dam).

Edited by Singularity
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http://onlinelibrary.wiley.com/doi/10.1002/2013JD021343/abstract

-> we are in a declining phase of the solar cycle.

Using 13 solar cycles (1869–2009), we study winter surface temperatures and North Atlantic oscillation (NAO) during four different phases of the sunspot cycle: minimum, ascending, maximum, and declining phase. We find significant differences in the temperature patterns between the four cycle phases, which indicates a solar cycle modulation of winter surface temperatures. However, the clearest pattern of the temperature anomalies is not found during sunspot maximum or minimum, but during the declining phase, when the temperature pattern closely resembles the pattern found during positive NAO. Moreover, we find the same pattern during the low sunspot activity cycles of 100 years ago, suggesting that the pattern is largely independent of the overall level of solar activity.

 

So the pattern described by Chio could be the right one.

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Thanks Chio for such a superb opening Post, started to follow

And try to understand this thread last year, and with such

Excellent posts from the knowledgeable posters in this thread

I am starting to understand (although still a long way to go) and

Learn this subject of the weather, thanks again and keep up

The good work.

C.S

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Ah.. The first proper sign of winter approaching, not the geese flying overhead, leaves falling from trees but Chiono opening the Strat thread! The second sign naturally is the Berlin strat charts fully opening for business on the 1st of November :-)

Fantastic summary, as always, Chiono, probably cementing most people's thoughts, which is much less (on occasion, wild!) optimism aka 14/15's E-QBO / high snow cover pre-winter frenzy and a more tempered W-QBO / declining solar cycle / dice generally less loaded on paper viewpoint. But as always a strong EL Nino will be the wild card here, plenty up for grabs. Sustained Wave1 activity looks a likely outcome and as we know displacement can be good for us but more often than not a thorn in our side as cold plunges down through Eastern Europe or away to our west down through the Mid Atlantic, possibly the form horse this time around. But better have wave activity than not, especially early winter as the vortex will be winding itself up and being fuelled from the W-QBO as well no doubt.

Less proper sustained blocking but with a bit of luck thrown in, I can see a couple of real cold snowy spells coming about in the way 1981 produced. Now that sounds like wild optimism! :-)

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Hi Chio, first of all many thanks for this wonderfull summary! I will give it some attention to the weather geeks in the Low Countries.

 

Two small things. In the first selection of years (december chart) I noticed 1962. I think you mean 1982?

 

And in Januar 1998 in stead of 1996?

The reanalysis data isn't that clear. I used yr's 82/83, 87/88, 97/98, 02/03 - perhaps I should have included 57/58 as well and if I had have done then DEC and Jan would have been the same, but Feb would have had a completely different look to it because of the Feb 58 SSW.

 

post-4523-0-13764900-1445171212_thumb.pn

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While not Nino's, those strat charts do remind one a little of winters 09 and 11. They were both +QBO winters.

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http://www.terradaily.com/reports/Forecasters_look_higher_for_clues_to_winter_weather_999.html

 

According to this publication, stratospheric forecasting can double the accuracy of forecasts for 2-4 weeks ahead.

 

 

Fantastic summary there as usual Chiono. I've looked at 500 mb height composites for February under W QBO and a strong El Nino and found a signal for anomalously high pressure west of the UK with a trough over Scandinavia... but no signal for the high latitudes either way, despite that vicious looking 10 mb composite. Delays working down to the troposphere perhaps?.

 

The high heights west of the UK appear to be in large part a consequence of the Pacific jet barreling into the Atlantic from around Florida to The Azores Isles.

 

 

Having said that, there's an interesting progression when looking at 10 mb, 30 mb and 100 mb levels for February. I've used 1958 instead of 2003 (i.e. only strong El Nino + W QBO winters) but the theme is broadly similar:

 

FebStrat_10_30_100mb_GPH.PNG

 

Increasing signs of a ridge over Greenland, but more west-based in terms of the -ve NAO... which is in line with your concerns but could be adding to the strength of positive height anomalies west of the UK at the 500 mb level (which are around +10 dam).

Hi thanks singularity. The publication that you quote is based from the paper linked to by Tripathia and Charlton et al in the first post (http://iopscience.iop.org/article/10.1088/1748-9326/10/10/104007 ) and also in the last thread - the forecasting by the ECM improves in both Vortex Intensification periods and SSW's.

 

We can see in VI strong events that if anything over the UK the increased temperature anomaly observed is slightly underestimated by the model through weeks 1-4 but overall the accuracy if very good

 

post-4523-0-39699500-1445177063_thumb.pn

 

Whereas typically in weak vortex events the observed overall model accuracy is again improved compared to average but week 4 there is an overestimation of negative anomalies over northern Eurasia - but fairly accurate for the UK

 

post-4523-0-05923800-1445177435_thumb.pn

 

Your findings regarding anomalies towards the troposphere are accurate and with a 'ridgy' Atlantic there may be periods where this exteneds towards us leaving benign 'warm' high pressure episodes this winter.

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I thought a strong El Nino typically brings a mild first half of winter and cooler 2nd half. Interesting that the analogues are going for the opposite. So many mixed signals this year.

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Hi thanks singularity. The publication that you quote is based from the paper linked to by Tripathia and Charlton et al in the first post (http://iopscience.iop.org/article/10.1088/1748-9326/10/10/104007 ) and also in the last thread - the forecasting by the ECM improves in both Vortex Intensification periods and SSW's.

 

We can see in VI strong events that if anything over the UK the increased temperature anomaly observed is slightly underestimated by the model through weeks 1-4 but overall the accuracy if very good

 

attachicon.gifScreen Shot 2015-10-18 at 14.56.25.png

 

Whereas typically in weak vortex events the observed overall model accuracy is again improved compared to average but week 4 there is an overestimation of negative anomalies over northern Eurasia - but fairly accurate for the UK

 

attachicon.gifScreen Shot 2015-10-18 at 14.56.59.png

 

Your findings regarding anomalies towards the troposphere are accurate and with a 'ridgy' Atlantic there may be periods where this exteneds towards us leaving benign 'warm' high pressure episodes this winter.

 

You're very welcome  :hi:

 

Taking the two very strong El Nino events from the past half-century in isolation (82/83 and 97/98) does produce 500 mb anomalies that feature a band of positive height anomalies extending right across the North Atlantic and just about into the UK. Given how the surface patterns relate to this, I am keen to make sure I have other things to occupy my mind in the face of 'limpet highs' sat in undesirable locations. Let alone combinations of that with high pressure over Europe which seems likely to happen at times given how the extended Pacific jet displaces the Azores High to the east (or so it appears from those analogue years).

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Congrats on a new season and a great new intro post! :)

 

I have nothing major to share, just some forecast anomalies, showing the GEFS and GFS going for a bit less organised vortex going into November, as expected.

 

geopotentialheightisobar.png geopotentialheightisobar.png

 

temperatureisobaric-in-1.png temperatureisobaricens-i.png temperatureisobaricunwei.png

 

The zonal wind zonal mean forecast from GFS does show a less organised vorex, also compared to this time last year. Of course its just a forecast. 

 

u-componentofwindisobari.png u-componentofwindisobari.png

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Sorry guys, I am looking for the archived first Strat thread or the earliest one available. Can't seem to find it, although I am on a phone - which probably doesn't help- can anyone link it for me please ?

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All the previous strat threads are linked to in the first post....

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Sorry guys, I am looking for the archived first Strat thread or the earliest one available. Can't seem to find it, although I am on a phone - which probably doesn't help- can anyone link it for me please ?

Is this what you are looking for? :)https://forum.netweather.tv/topic/50299-stratosphere-temperature-watch/

You should have seen it rooted at the bottom of the post.

Edit: it is great to see this thread up and running but I'll remain as bystander it is quite a complicated subject.

Edited by Daniel*
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Top quality intro, as always. :good:

 

I had posted the sessions for the international conference on sun -climate relations in the climate thread but there was a lot of interesting new research (particularly on Wednesday)  that relates to the stratosphere.

 

Conference topics with abstracts.

 

http://scc.geomar.de/frontend/index.php?page_id=506&v=List&do=0&day=121

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Top quality intro, as always. :good:

 

I had posted the sessions for the international conference on sun -climate relations in the climate thread but there was a lot of interesting new research (particularly on Wednesday)  that relates to the stratosphere.

 

Conference topics with abstracts.

 

http://scc.geomar.de/frontend/index.php?page_id=506&v=List&do=0&day=121

 

 

Thanks Nouska - looks like some quality topics in there. Do you subscribe to the strat list?

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Excellent introduction

 

It will be interesting to see how the strong Nino matches up with the +QBO. I'd place bets that the strong Nino with wave breaking events in the N. Pacific and perhaps N. Atlantic that will eventually win out but I think it will be rather difficult. As you've stated, the chances of a SSW are heightened with a Nino. Should be a fun battle. 

 

Cheers from across the pond on another insightful thread. There is much to be learned about the troposphere-stratosphere dynamic. 

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As ever Chiono a superb summary of the runners and riders in this winters weather stakes.

 

Have followed the start thread for a few years now since the days of the late lamented Glacier Point.  it is clear that trying to make prognostications for the coming winter

without taking into account the potential state of the vortex and strat connections is really just p*****g in the wind.

 

Look forward to your future updates Chiono  and also posts from other knowledgable guys like Lorenzo, Recreteos etc.

 

Thanks for all your hard work and the time you put in.

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As ever Chiono a superb summary of the runners and riders in this winters weather stakes.

 

Have followed the start thread for a few years now since the days of the late lamented Glacier Point.  it is clear that trying to make prognostications for the coming winter

without taking into account the potential state of the vortex and strat connections is really just Tut**g in the wind.

 

Look forward to your future updates Chiono  and also posts from other knowledgable guys like Lorenzo, Recreteos etc.

 

Thanks for all your hard work and the time you put in.

The late lamented GP is back with us. Happy days  :)

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