Autumn & Winter 2023---2024 Stratospheric Polar Vortex. Events, Analysis, Discussions AND Outlooks

[frederiksen90]

Is there SUDDEN stratospheric warming brewing? Or what happens? It is therefore an extremely interesting change that has occurred in a short time. Therefore perhaps suddenly? EC46 has shown a stable strengthening vortex with a slow weakening at the end for a long time. But now the strong intensifying warming in 10 hPa from the North Pole on its way to Canada/Greenland over the last two days shows.

EC 46 on Sunday:

https://charts.ecmwf.int/streaming/20231121-2000/47/render-worker-commands-76898cbbf-zdbjw-6fe5cac1a363ec1525f54343b6cc9fd8-rHarLF.png?fbclid=IwAR0cP_ymedoQZbRZKavBj2J2Mf24WvN8uQXUItKx4fHPZBx09ia-na7jVbM

EC46 today:

https://charts.ecmwf.int/streaming/20231121-2000/8a/render-worker-commands-76898cbbf-z7r8s-6fe5cac1a363ec1525f54343b6cc9fd8-PQSOm2.png?fbclid=IwAR3Fkhjtjlkb2dn2rDGas4NDCrLRBGX6p3xdkIHyVW2pEj8p0pJFWkAQ85w

 

And just look at the change in the zonal wind from Sunday to today:

https://charts.ecmwf.int/streaming/20231121-1240/5d/ps2png-worker-commands-76898cbbf-5kktb-6fe5cac1a363ec1525f54343b6cc9fd8-eOe5nM.png?fbclid=IwAR3twESXABbKnetwZf0WI3gVd2qfyF7wXuG_bzpiG_SvMcJaX64rXE1pGBk

 

https://charts.ecmwf.int/streaming/20231121-2000/da/ps2png-worker-commands-76898cbbf-f5rht-6fe5cac1a363ec1525f54343b6cc9fd8-rdu4pd.png?fbclid=IwAR3Fkhjtjlkb2dn2rDGas4NDCrLRBGX6p3xdkIHyVW2pEj8p0pJFWkAQ85w

 

There is something to keep an eye on. It has appeared like a troll from a box with the change from one day to the next, But now suddenly some interesting development happens. And it is perhaps connected with the Atlantic ridge connecting Scandinavia and increasing wave 2 activity? Something is being written here:

 

The tripole in the Atlantic has also developed. The jet stream is much further south than expected. Perhaps as a result of the combination of ice growth and solid cold over Scandinavia, the contrast between cold in the Nordics and warm in Southern Europe has increased. So the flow is further south than normal even in a strong stratosphere. And now with good trends also in the stratosphere. I think it matches very well with 2009/10. I think Europe will get plenty of winter this year.

Edited November 21, 2023 by frederiksen90

[Mike Poole]

2 hours ago, frederiksen90 said:

There is something to keep an eye on. It has appeared like a troll from a box with the change from one day to the next, But now suddenly some interesting development happens. And it is perhaps connected with the Atlantic ridge connecting Scandinavia and increasing wave 2 activity? 

The tripole in the Atlantic has also developed. The jet stream is much further south than expected. Perhaps as a result of the combination of ice growth and solid cold over Scandinavia, the contrast between cold in the Nordics and warm in Southern Europe has increased. So the flow is further south than normal even in a strong stratosphere. And now with good trends also in the stratosphere. I think it matches very well with 2009/10. I think Europe will get plenty of winter this year.

I think it is definitely connected with the connecting ridge through Scandi into Russia, as that only appeared in the modelling yesterday, and today the models seem confident about it.  For a good fortnight previously, high pressure had vanished from that area and the strat warming threat had receded on the ECM 46 accordingly.  It’s back now!

Re, the tripole, is it known if the tripole has emerged because of the southerly tracking jet (which has been so for a while now on average), or is the southerly tracking jet caused by the tripole?  

Edited November 21, 2023 by Mike Poole

[summer blizzard]

3 minutes ago, Mike Poole said:

I think it is definitely connected with the connecting ridge through Scandi into Russia, as that only appeared in the modelling yesterday, and today the models seem confident about it.  For a good fortnight previously, high pressure had vanished from that area and the strat warming threat had receded on the ECM 46 accordingly.  It’s back now!

Re, the tripole, is it known if the tripole has emerged because of the southerly tracking jet (which has been so for a while now on average), or is the southerly tracking jet caused by the tripole?  

Tripole is chicken and egg. 

But it's worth saying that while there is a tripole it's further north than is optimum (whether this impacts the pattern down the line is speculative of course).

[Chesil View]

Is there a definitive list of canadian warming events anywhere that anyone knows of?

[Premiere Neige]

An interesting read and something I hadn't even considered:

How Canada's wildfires are warming the stratosphere

WWW.BBC.COM

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Extreme wildfires are increasing due to rising emissions, but they also disrupt the climate in return. Weighing up the overall impact, however, is tricker than it seems.

 

[bluearmy]

I wonder if we’ll see Ed popping up soon @chionomaniac ………

this all looks v interesting high up 

Edited November 22, 2023 by bluearmy

[andy989]

1 hour ago, bluearmy said:

I wonder if we’ll see Ed popping up soon @chionomaniac ………

this all looks v interesting high up 

I was wondering the same 

[SqueakheartLW]

6 hours ago, Premiere Neige said:

An interesting read and something I hadn't even considered:

How Canada's wildfires are warming the stratosphere

WWW.BBC.COM

---

Extreme wildfires are increasing due to rising emissions, but they also disrupt the climate in return. Weighing up the overall impact, however, is tricker than it seems.

 

Now we know how to guarantee the UK a cold winter every year. Not good news for Canadians though.

 

[Premiere Neige]

17 minutes ago, SqueakheartLW said:

Now we know how to guarantee the UK a cold winter every year. Not good news for Canadians though.

 

I shouldn't laugh but...

[bluearmy]

Ec46 on the same page again today 

[Formula_1_Fan]

I've seen a few posts about the effect of the Canadian wildfires on the strat but I was wondering if anyone had anymore info on the effect of the Tonga eruption from  Jan 2022.

 

Now i know thats a long time ago now but a few articles have been cropping up recently about how it seems to have changed things a fair bit up in the stratosphere. I've linked an article below, it focuses a lot on the southern hemisphere but it does mention "Previous studies found that the eruption increased water vapor in the stratosphere by 10% worldwide", along with a whole load of other changes with things like ozone being effected.

 

From what I've read it could take a number of years to return to normal, it would be great to find a study on the impact its had in the northern hemisphere if anyone has a link.

 

Anyway here is the link I mentioned earlier:

 

Study examines how massive 2022 eruption changed stratosphere chemistry and dynamics

PHYS-ORG.CDN.AMPPROJECT.ORG

---

When the Hunga Tonga-Hunga Ha'apai volcano erupted on January 15, 2022 in the South Pacific, it produced a shock wave felt around the world...

 

 

[Mike Poole]

Does anyone know if there is any formal defined criterion for a Canadian warming.  I don’t think we are expecting a reversal at 10hPA 60N as for a SSW, there certainly wasn’t in 1962, but these things have been defined in the past, I just wondered on what basis.

[Metwatch]

1 hour ago, Mike Poole said:

Does anyone know if there is any formal defined criterion for a Canadian warming.  I don’t think we are expecting a reversal at 10hPA 60N as for a SSW, there certainly wasn’t in 1962, but these things have been defined in the past, I just wondered on what basis.

AO/PV Blog Update | Verisk's Atmospheric and Environmental Research

WWW.AER.COM

The blog is a long read but it does touch on some Canadian warming stuff, written by Judah Cohen. It can lead to SSW's later in the winter i think but Canadian warming themselves don't lead to SSW events straight away I wouldn't think.

A quote from the article: "The models seem to be suggesting a pattern that is referred to as a Canadian warming with high pressure ridging in the polar stratosphere over Canada and not near the Dateline and/or Alaska as in PV stretching."

"Canadian warmings can be precursors to SSWs if the forcing persists, which seems to be implied for the CFS forecast for what that is worth. Setting up the potential for an SSW in January."

Edited November 23, 2023 by Metwatch

[MattH]

The Canadian Warming is gathering pace for early December now. The drop in ZW at 10hPa has increased significantly as well over the last few days. CW's rarely lead to an SSW, often pushing the main vortex towards the Russian side of the pole.

How this will influence the coming weeks is very uncertain as clearly there remains little strat and trop connection as it is, despite a recent downwelling of westerlies, but that event has come to an end. At a minimum, a displaced vortex towards Russia can mean that it reduces the risk of the main tPV setting up over Greenland, while, importantly, this weakening of the vortex is likely to aid, to an extent, in reducing the chances of the sPV influencing the tPV anyway. It also brings about the threat of the sPV being properly 'taken down' deeper into winter, now it's been knocked about at this (very) early stage in the season.

Fascinating winter synoptics already and it's not even winter yet!

 

[Metwatch]

You can see the lack of strat and trop connection with the latest GFS run quite nicely. The zonal mean U wind component at 60N has all those blues below 300 hPa meaning very weak westerlies and at times reversing to easterlies, due to the blocking heights north of the UK now being established. However above the 30hPa level we see all those oranges and red where the westerlies are much stronger.

An SSW event would turn the strat winds at the top from westerlies to easterlies with those blue / purple colours downwelling, but at the moment at least next few weeks little to no signs of that.

Edited November 24, 2023 by Metwatch

[Dennis]

its very interesting to see what the C.warming will do for strato 

Edited November 24, 2023 by Dennis

[lorenzo]

This should get everyone up to date.

The importance of the polar vortex at 100 hPa – Simon H. Lee

SIMONLEEWX.COM

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The most commonly-used diagnostic of the strength of the stratospheric polar vortex is the zonal-mean zonal wind at 10 hPa (~30 km) and 60°N (U10-60), which is westerly during winter. It is an easy diagnostic to...

 

[lorenzo]

Briefly the conundrum, base state has crashed... AAM would normally put is in the side of things which are not blocking, the MJO phase ( really curious as to what is the truth here, Cyclones, ERWs, KWs, noise vs true MJO, the yellow blob at the foot of the chart is arguably the one to watch. And, finally the best site for the strat which shows real time movies of Vortex behaviour at diff. levels, we can see 100hPA on that still which provides credence for EC 12z tonight.. 192 would be as far as I go here though as these blocks are delicate and you can see on the vorticity plot below a classic tail which may erode the 500hPa lock out of the Atlantic.

On CWs - it is a shame Berlin table did not continue to update, these were 'a thing' in the 80s when identified by Labitzke, however almost ghosted for a long time and were not classified. Nov CWs are more prevalent, Dec CWs - very rare -21 and 43 yrs ago - so literally no analog, composite or anything which would inform with any skill progression here. 1981 being 2 years into nascent strat sat monitoring then one season where classified. We have seen over the last few years though decent pulses of wave activity akin to CW ahead of the classic Vortex Intensification period, which i am unsure about how to gauge (i) these events were always likely prior to VI period and not monitored closely enough until the new sites to see the strat came on-line since 2018 > to date, or, these are genuine CWs akin to 80s view, would suspect the former.

All told, CW does it's thing, vortex impinged distended, serendipty in the wave breaks does it's thing to build the Scandi break, breaks the routine regime, modelling hints at both weakeness in the lower vortex and also mechanics over North America greenland which are supportive ( currently / tentatively ) of some notable blocking. If not, then next MJO passage may be more telling on the vortex mechanics this year and how impactful the impact of wave breaks will be on vortex and our regimes here.

[lorenzo]

Also found this by accident this week re: later season action..

Just a moment...

AGUPUBS.ONLINELIBRARY.WILEY.COM

Meteofrance you dark horses is point 1

And 2003 - needs some retrospective.

CW table referenced above is here 

North Pole temperatures • Atmospheric Dynamics • Department of Earth Sciences

WWW.GEO.FU-BERLIN.DE

 

 

[Dennis]

The vortex gets a BIG KICK next month 

 

[Andy8472]

Warming showing up quite well, Hi all btw

[Dennis]

strato is decreasing zonal m/s on warming (canadian) 

 

[Catacol]

On 22/11/2023 at 10:00, Chesil View said:

Is there a definitive list of canadian warming events anywhere that anyone knows of?

Try this article.. 

https://www.atmosp.physics.utoronto.ca/SPARC/News15/15_Labitzke.html

[Chesil View]

6 hours ago, Catacol said:

Try this article.. 

https://www.atmosp.physics.utoronto.ca/SPARC/News15/15_Labitzke.html

Many thanks Catacol

[BLAST FROM THE PAST]

On 15/11/2023 at 16:12, Don said:

Not expecting December to be up to much and that's supported by the seasonal models really.  Anything more would be a bonus and December more likely to be a continuation of November, with any real interest reserved until the New Year at least?

Looks like a bonus is coming

 

BFTP