Stratosphere and Polar Vortex Watch

[Don]

1 hour ago, StretfordEnd1996 said:

It will only be a 'shame' if it's true and it comes off

Right now none of us can possibly have any idea what's going on with it

You’re quite right and we will just have to wait and see how things develop.

[knocker]

Troposphere‐Stratosphere Coupling in Subseasonal‐to‐Seasonal Models and Its Importance for a Realistic Extratropical Response to the Madden‐Julian Oscillation

Quote

Abstract

The representation of upward and downward stratosphere‐troposphere coupling and its influence on the teleconnections of the Madden‐Julian oscillation (MJO) to the European sector is examined in five subseasonal‐to‐seasonal models. We show that while the models simulate a realistic stratospheric response to transient anomalies in troposphere, they overestimate the downward coupling. The models with a better stratospheric resolution capture a more realistic stratospheric response to the MJO, particularly after the first week of the integration. However, in all models examined here the connection between the MJO and vortex variability is weaker than that observed. Finally, we focus on the MJO‐SSW (sudden stratospheric warming) teleconnection and specifically initializations during the MJO phase with enhanced convection in the west/central pacific (i.e., 6 and 7) that preceded observed SSW. The integrations that simulated a SSW (as observed) can be distinguished from those that failed to simulate a SSW by the realism of the Pacific response to MJO 6/7, with only the simulations that successfully simulate a SSW capturing the North Pacific low. Furthermore, only the simulations that capture the SSW subsequently simulate a realistic surface response over the North Atlantic and Europe.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JD032043#.Xsfy3bExlZo.twitter

[Singularity]

On 22/05/2020 at 11:37, summer blizzard said:

Difficult to tell from such a crude chart but its worth saying that in 88/89 we did have a full 8 months at a standard deviation of neutral-negative because 30hpa values started to rise before returning to normal. It's also worth saying that from the monthly layered values in the 2015 cycle the 20hpa and 30hpa values never got lower than +9 before rebounding whereas in this cycle we are at -7 and -3 meaning that we do have easterlies throughout the atmosphere (while they've weakened at 20hpa they are still in slow decline at 30hpa) so i'm not sure this one will fail in totality. 

 

Interesting spot there. Seems that the easterlies descended very fast but then stalled for a time.

The current event has seen a slower descent with some interference at 30 mb. True that the winds are just about easterly - but it's so slight that I'm not sure whether it should count or not.

Which is to say, I'm not sure if a near-neutral wind layer can have a reflecting effect on the easterlies above.

Definitely a different manner of event to the 2015-16 one. Or at least, a sub-type.

I hope you're right to anticipate this one not failing totally. I've been looking forward to a less westerly type winter (though I can't deny that even with the treasured just past solar minimum + eQBO combination, that's not a guarantee!).

[JeffC]

On 22/05/2020 at 16:54, General Cluster said:

TBH, Jeff, I don't think so; I suspect that changes to the QBO, are more-likely linked to AGW: the expansion of the Hadley Cell, perhaps?

I suspect (and always have suspected) that many of the 'effects' of Solar minima may be highly exaggerated? 

Cheerio, Elvis!

I take your point Pete, but equally there seems to have been a correlation with Launder and Dalton minima and reduced temperatures, although I grant that didn't have the backdrop of rising temperatures...

Curious to see if this minimum will persist as has been hypothesized in some places....

[summer blizzard]

39 minutes ago, JeffC said:

I take your point Pete, but equally there seems to have been a correlation with Launder and Dalton minima and reduced temperatures, although I grant that didn't have the backdrop of rising temperatures...

Curious to see if this minimum will persist as has been hypothesized in some places....

It won't persist, we will just see a weak maximum.

[Don]

54 minutes ago, summer blizzard said:

It won't persist, we will just see a weak maximum.

Similar to SC24 I suppose.

[Don]

3 hours ago, Singularity said:

I hope you're right to anticipate this one not failing totally. I've been looking forward to a less westerly type winter (though I can't deny that even with the treasured just past solar minimum + eQBO combination, that's not a guarantee!).

I'll second that! 

[JeffC]

1 hour ago, summer blizzard said:

It won't persist, we will just see a weak maximum.

Are there any credible predictions on SC 26?

[JeffC]

15 minutes ago, JeffC said:

Are there any credible predictions on SC 26?

Something here for perusal

WhatsOrb

WWW.WHATSORB.COM

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WhatsOrb is the only Global Sustainability Exchange platform where users are the authors of content, can directly get in contact with each other and are identified...

 

[knocker]

 

[knocker]

Regarding another QBO disruption, not that I'm suggesting the same reaso, might be worth looking at this again

Dynamics of the Disrupted 2015/16 Quasi-Biennial Oscillation

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-16-0663.1

[knocker]

wrong thread

 

Edited May 28, 2020 by knocker

[SqueakheartLW]

15 hours ago, knocker said:

Regarding another QBO disruption, not that I'm suggesting the same reaso, might be worth looking at this again

Dynamics of the Disrupted 2015/16 Quasi-Biennial Oscillation

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-16-0663.1

Looks like the EQBO is just about to fail

Look just how weak the easterlies have got above 30hpa and this has happened rather quickly too. One thing I did notice in the link above is reference to a developing easterly anomaly centred on 40hpa and look at the chart, 40hpa is where the fastest easterlies are right now. Unless this anomalous easterly jet pushes upwards and kills off the neutral to weakly westerly winds above then this will go down as possibly the weakest and shortest EQBO on record

This second chart shows the QBO at different levels of the atmosphere from 10hpa down to 100hpa. The Westerlies are the brown sandy coloured areas and the easterlies are the greens and blues. The 2017/2018 EQBO descended without any problems as can easily be seen on the left of the chart. On the right you can see the strange pattern that has developed really since the start of winter 2019/2020 with increasing easterlies forming under the remains of the last WQBO

By the time you get to the most recent data on the far right of the chart it is clear the EQBO has been almost killed off by the lingering westerlies around 30hpa combined with new westerlies descending down from 10hpa too. Is this a temporary blip and the easterlies will resume or is this the last days of the EQBO above 30hpa for a while now and we will get another period of westerlies again over the next year at least

I did also note that there were references to 1987/1988 and 2010/2011 in the link above too. 

In the above chart the QBO phases are seen as white for easterlies and grey for westerlies

1 - There is the clear and obvious easterly jet that formed in 2016 at around 40hpa which was responsible for killing off the easterly QBO in 2016. This formed when the EQBO had only just begun to descend and was enough to kill it off until 2017

2 - The latest descending EQBO is more advanced than the 2016 one but the anomalous easterly jet at 40hpa is also stronger than the 2016 one. What both 2015/2016 and 2019/2020 have in common is a record strong polar vortex in both of those winters

3 - When looking at the other years mentioned (1987/1988 and 2010/2011) it was mentioned that the westerlies didn't turn to easterlies at 40hpa but when looking at the chart there is a clear weakening of the westerlies at 40hpa in both of those N Hemisphere winters before they pick up speed again. Also in 2010/2011 there was quite a strong polar vortex too

[Chesil View]

Sorry if this is the wrong thread but I,m wondering about the May sea surface temp connection with following winter Synoptics and how that is looking this year.

Dipoles ,tripoles etc.

[summer blizzard]

1 hour ago, Broadmayne blizzard said:

Sorry if this is the wrong thread but I,m wondering about the May sea surface temp connection with following winter Synoptics and how that is looking this year.

Dipoles ,tripoles etc.

Cold over warm so a +NAO signature albeit the negative anomaly extends further south than normal.

[philglossop]

Quick question

If the QBO is showing in the W but in an E descending, did we not see the same blip in 1980 and 1983 before the E increased and descended properly. Looking at this photo did this not happen? 

[mushymanrob]

3 hours ago, philglossop said:

Quick question

If the QBO is showing in the W but in an E descending, did we not see the same blip in 1980 and 1983 before the E increased and descended properly. Looking at this photo did this not happen? 

I cant answer that, but summer 80 was poor whilst summer 83 turned fantastic.

Both the following winters were pretty unremarkable.

[philglossop]

5 hours ago, mushymanrob said:

I cant answer that, but summer 80 was poor whilst summer 83 turned fantastic.

Both the following winters were pretty unremarkable.

Thanks for the response Mushyman.

Its curious as I know the E QBO failed in 2016 hence the concern its failing now, but those blips are there for 1980 and 1983. But my knowledge isnt as strong on the QBO at all. 

[summer blizzard]

Slow it may be but the April numbers for 30hpa confirm slow progress. Now at -0.41 on a standardised basis (in early 89 it actually went backward for a month).

[Duane S.]

Where on earth do we go from here? The westerlies at the bottom have turned Easterly. We virtually have Easterlies right through from top to bottom.

This normally only occurs for a short period of time as the westerlies at the bottom finally dissipate and before a new westerly burst starts downwelling through 10hpa. Even then, many cycles don’t even produce this outcome, as in, the westerlies nearer the bottom don’t reverse in time before a new clear westerly burst appears at the top.

 

So it’s not the fact we have (in all likelihood) a very short period of time of a near total Easterly that is unusual, it’s the circumstances that have led to it that is unprecedented in recorded times.

 

This does appear to be another disruption event, albeit quite different to the last one a few years back. This picture below shows very graphically how weak the Easterlies have been and that, on the face of it, that we are heading quickly away from our weak E-QBO and back towards a new W-QBO.

That said, there probably is still time for the Easterly regime to somewhat double back, intensify and re-establish? And I wonder if we are indeed seeing just that. Easterly winds higher up have increased somewhat and that strong anomalous well-defined Easterly wind at 40hpa looks to be backing off I’d say, so maybe there’s some hope yet.

Interesting to see what happens next, I wouldn’t want to have to call it, that’s for sure.

Edited June 7, 2020 by s4lancia

[philglossop]

Mmmm

Looking like the W are starting and theres a link or very nearly a link from the Strat..

[Don]

14 hours ago, philglossop said:

Mmmm

Looking like the W are starting and theres a link or very nearly a link from the Strat..

Another winter with a W-QBO?!   More concerning is the fact we might be looking at another E-QBO failure so soon after the last one in 2016!  True QBO records only go back to the 1950's, but clearly something strange is going on. 

Edited June 19, 2020 by Don

[karyo]

On Friday, June 19, 2020 at 22:28, Don said:

Another winter with a W-QBO?!   More concerning is the fact we might be looking at another E-QBO failure so soon after the last one in 2016!  True QBO records only go back to the 1950's, but clearly something strange is going on. 

It looks like we will have to place all our eggs in the solar minimum basket and hope for the best. 

[joggs]

We can still have a cracking winter with a W QBO. Eg,cold and snow.

Just less likely.

[summer blizzard]

Looking at the data for first year Nina's which went +QBO and were -PDO it seems that 1998, 2005, 2007, 2010 and 2016 are the most apt and essentially split into a camp of 1998, 2007, 2010 vs 2005 and 2016. 

While there's a generally strong signal for October and November (dry, settled and probably cool) there is a lot of divergence come winter. 

There are problems with 2005, 2007 and 2016 though in that 2005 and 2007 both came into winter with a -QBO peaking in the Autumn and the 2016 Nina kind of died come winter 2017. While 1999 and 2010 are both good ONI, QBO and PDO matches (assuming we crank out a strong ish Nina) they had pretty divergent winters until Feb.

Very complicated picture.