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

[Mike Poole]

This new warming or split, very much driven from the bottom up, it would seem, GFS 6z shows this nicely on the left plot, as the weaker winds are upwelling into the higher strat:

You can see the -AO developing at the bottom in the latter half of the run.  Not an SSW on this run, mind.

Given this profile, I think I would expect any SSW to reinforce the existing pattern on occurance, rather than imprint anything new on the situation?

[lorenzo]

Stronger looking heat flux evident later in the month.. an already weakened SPV under renewed attack..

[Kiwi]

 

[Andy8472]

GFS flirting with the zero line & keeps bouncing around with GEPS around zero, the ECM 46 should be interesting later.

If nothing else the vortex looks very weak atm which is only a good thing in my books

[Bricriu]

What are the thoughts  on Judah Cohens latest update?

Edited January 5 by Bricriu

[Windysun1]

Not what we want to see to say the least and you would wonder is that what some models are picking up as regards poorer amplification of the GLH...

Although personally i think it might be too early to call anything past 4 to 5 days. Alot going on in the strat ie warming at different levels that the models are still trying to interpret and alot we still dont fully understand about the strat. Complicated situation this science at the best of times

[bluearmy]

6 minutes ago, Windysun1 said:

Not what we want to see to say the least and you would wonder is that what some models are picking up as regards poorer amplification of the GLH...

Although personally i think it might be too early to call anything past 4 to 5 days. Alot going on in the strat ie warming at different levels that the models are still trying to interpret and alot we still dont fully understand about the strat. Complicated situation this science at the best of times

Isn’t that  NH set up is the current week 2 modelling which is supposed to give us cold 

I assume he’s speaking about a strengthening vortex for feb into march and a lack of HLB for spring and summer. Excellent 

however, I would have thought the reversals ongoing will lead to repeating downwelling waves to the back end of feb 

[Windysun1]

9 minutes ago, bluearmy said:

Isn’t that  NH set up is the current week 2 modelling which is supposed to give us cold 

I assume he’s speaking about a strengthening vortex for feb into march and a lack of HLB for spring and summer. Excellent 

however, I would have thought the reversals ongoing will lead to repeating downwelling waves to the back end of feb 

You could be correct bluearmy but i took up differently. 

Infact if you look at the lack of blocking at the end of the ECM run..anemic is putting it mildly. Does it have any relevance to his post i dont know but its certainly disappointing. Il give it to Sunday to see if there is any back tracking.

Im gone off on a bit of a tangent here not toally strat chat. Sorry mods.

Edited January 5 by Windysun1

[bluearmy]

29 minutes ago, Windysun1 said:

You could be correct bluearmy but i took up differently. 

Infact if you look at the lack of blocking at the end of the ECM run..anemic is putting it mildly. Does it have any relevance to his post i dont know but its certainly disappointing. Il give it to Sunday to see if there is any back tracking.

Im gone off on a bit of a tangent here not toally strat chat. Sorry mods.

It’s all uncertain top to bottom 

[Fiona Robertson]

Today's eye candy. 10 hPa.

Edited January 6 by Fiona Robertson

[Bricriu]

Is the easterly phase of the QBO aiding us this year somewhat.? Would these warmings that are falling short of a major ssw not be enough if it was in a westerly phase?

[Fiona Robertson]

I've done this as a separate post cos I am a numpty when it comes to editing posts with an image in. I marked the centre of the area of circulation in the image above, it's way towards the right,to use as a reference point andthen I cycled through the various altitudes. Images are 70 hPa, 250 hPa and 500 hPa. Notice that at 70 hPa the centre of circulation has relocated, but the overall elongated shape remains. At 250 hPa, the elongated shape remains, but there are now 2 distinct areas of circulation, one on the left, one on the right, but the centre of the one on the right is in the same place as the 70h Pa one. At 500 hPa same thing.

What point am I making? None, it's more of a question or two. Is the polar vortex tilted, ie is the top of it being pushed over by the warming high? And is the warmer area to the west of the UK at 500 hPa pushing into the vortex from a lower altitude.Tomy completely untrained eye it appears that the big area of warming is elongating the vortex and then at lower altitude the vortex could be split and the split propagate upwards?

 

[lorenzo]

Given the pace of the model thread jumping in here to add some output, almost too much to look at right now given NWP output, Strat Output, MJO in play and AAM turning the corner.

First off picked the 30hPa level given the top of the envelope projections shown in Merra for a couple of variables driven by the strong W1 warming.

Lovely view of the progression of the warming and the impacts on the vortex as it distends and is split.

Also viewable as animation here  , graphics not as great - but does highlight another pulse of warming out at D10.

Then the 100hPa look which is probably the most exciting one currently in terms of echoes to NWP and what is driving chaos and variability.

Vortices splitting at just 72 hrs and the energy shearing from the Canadian lobe spirals south - whipping across the Atlantic. The Canadian lobe pulling back, whilst the Siberian lobe progams the Northerly regime. Interesting to analyse these views as the exchange of energy between the daughter vortices provides neat insight into what may translate into NWP.

It is a delicate balance of separation from the split in terms of how the vortices interact. Friday update saw only brief separation and energy transfer from the parent Siberian vortice back to Canada - reinvigorating the aforementioned filament and placing further pressure on the ridge attempt into Greenland, so much so in fact - it looked to be heading to a Scandi solution before getting stuck halfway house in the 'no mans land' which leaves us looking at less than appealing from a cold perspective output.

This break is far from resolved yet and given it is happening within next 72 hrs, twists and turns to come.

In relation to the MJO - beginning to look more coherent and composites show the direction of travel imprinting, it is never a=b for these so use as guidance, last updated in 2014 so nearly a decade of data not in them.

A vortex already heavily assaulted this winter, technical SSW or not - it feels as good as one currently, with more duress ahead. Wondering if January is just an appetizer for February as AAM rebounds..

Finally a look at the development of the blocking regimes from Xmas Eve to date from EC as we progress from nowhere to the stuff we all like to see from a cold ( and dry) perspective in Winter.

 

Edited January 6 by lorenzo
Adding charts

[Andy8472]

6 minutes ago, Bricriu said:

Is the easterly phase of the QBO aiding us this year somewhat.? Would these warmings that are falling short of a major ssw not be enough if it was in a westerly phase?

Some good layman's term info on it from the metoffice

https://www.youtube.com/watch?v=LTkppqrmuLY

[Windysun1]

Sorry, i know im like a dog with a bone here but what is Judah comments here considering all the signals as posted above. Is it just in reference to the East Coast of the States that he sees an end to winter. Slightly bemused.

[Bricriu]

26 minutes ago, Andy8472 said:

Some good layman's term info on it from the metoffice

https://www.youtube.com/watch?v=LTkppqrmuLY

Fantastic video. Thanks  a lot for sharing it 

[lorenzo]

1 hour ago, Fiona Robertson said:

I've done this as a separate post cos I am a numpty when it comes to editing posts with an image in. I marked the centre of the area of circulation in the image above, it's way towards the right,to use as a reference point andthen I cycled through the various altitudes. Images are 70 hPa, 250 hPa and 500 hPa. Notice that at 70 hPa the centre of circulation has relocated, but the overall elongated shape remains. At 250 hPa, the elongated shape remains, but there are now 2 distinct areas of circulation, one on the left, one on the right, but the centre of the one on the right is in the same place as the 70h Pa one. At 500 hPa same thing.

What point am I making? None, it's more of a question or two. Is the polar vortex tilted, ie is the top of it being pushed over by the warming high? And is the warmer area to the west of the UK at 500 hPa pushing into the vortex from a lower altitude.Tomy completely untrained eye it appears that the big area of warming is elongating the vortex and then at lower altitude the vortex could be split and the split propagate upwards?

 

You are looking at the right things - yes.

To save you some work this site may help give a sense of the tilt in the vortex brought about by the Wave 1 forcing on the vortex. This links shows the tilt across the vortex structure vs height.

StratObserve Vertical Vortex Structure

STRATOBSERVE.COM

 The 3D view is also a great visibile representation. 

StratObserve 3D Vortex

STRATOBSERVE.COM

And finally, an easy way to view across the pressure levels from the Berlin site

Institute of Meteorology - Working Group Atmospheric Dynamics - ECMWF 240 h forecasts January 05 2024 12 UTC

USERS.MET.FU-BERLIN.DE

 

[Fiona Robertson]

10 minutes ago, lorenzo said:

You are looking at the right things - yes.

To save you some work this site may help give a sense of the tilt in the vortex brought about by the Wave 1 forcing on the vortex. This links shows the tilt across the vortex structure vs height.

StratObserve Vertical Vortex Structure

STRATOBSERVE.COM

 The 3D view is also a great visibile representation. 

StratObserve 3D Vortex

STRATOBSERVE.COM

And finally, an easy way to view across the pressure levels from the Berlin site

Institute of Meteorology - Working Group Atmospheric Dynamics - ECMWF 240 h forecasts January 05 2024 12 UTC

USERS.MET.FU-BERLIN.DE

 

Thank you! Fantastic links. I thought I was imagining things. If the vortex splits is it usually top down or bottom up? 

[BLAST FROM THE PAST]

19 hours ago, Windysun1 said:

You could be correct bluearmy but i took up differently. 

Infact if you look at the lack of blocking at the end of the ECM run..anemic is putting it mildly. Does it have any relevance to his post i dont know but its certainly disappointing. Il give it to Sunday to see if there is any back tracking.

Im gone off on a bit of a tangent here not toally strat chat. Sorry mods.

As you know I pm’d you way back in Dec that I anticipated a SSW early Jan ….for me it’s here and happening.  I don’t think Cohen is talking about the end of winter is nigh on over here.  I’ll stick to my gins, deep cold landing point 14-16 Jan…..bonus with initial thrust for S/SE in t48 hrs….but that will ease….main thrust remains 14-16.  This strat warming has/is imo currently being underplayed and will have a big knock on effect.  Don’t expect ‘continuous’ deep cold….but 

[lorenzo]

2 hours ago, Fiona Robertson said:

Thank you! Fantastic links. I thought I was imagining things. If the vortex splits is it usually top down or bottom up? 

The vortex can split at differing levels if elongated; top down warming can occur which may preclude splits happening lower in the vortex. Tropospheric led splits at lower levels are pretty much what we all like to see - given the notoriety of the 2009 SSW. Rather than top down or bottom up - we tend to view things as either displacement or split events impacting on the vortex.

[Notty]

40 minutes ago, BLAST FROM THE PAST said:

As you know I pm’d you way back in Dec that I anticipated a SSW early Jan ….for me it’s here and happening.  I don’t think Cohen is talking about the end of winter is nigh on over here.  I’ll stick to my gins, deep cold landing point 14-16 Jan…..bonus with initial thrust for S/SE in t48 hrs….but that will ease….main thrust remains 14-16.  This strat warming has/is imo currently being underplayed and will have a big knock on effect.  Don’t expect ‘continuous’ deep cold….but 

I’ll stick to my gins  ^^

Party on  

[Windysun1]

1 hour ago, BLAST FROM THE PAST said:

As you know I pm’d you way back in Dec that I anticipated a SSW early Jan ….for me it’s here and happening.  I don’t think Cohen is talking about the end of winter is nigh on over here.  I’ll stick to my gins, deep cold landing point 14-16 Jan…..bonus with initial thrust for S/SE in t48 hrs….but that will ease….main thrust remains 14-16.  This strat warming has/is imo currently being underplayed and will have a big knock on effect.  Don’t expect ‘continuous’ deep cold….but 

Indeed you did. Infact the UKMO is obviouly seeing something and have greater scope of data than what we have. It usually seems to pain them to mention "snow" They are now throwing it about as if it was Lapland. 

As i see it now the initial heights will collapse. The next and very potent energy phase as you say could be between the 14-16. This looks like been more Polar than continental. The longevity is the question this continuous attack on the strat might just be the trigger for extending such a potent spell.

I certainly hope so.

[Duane S.]

7 hours ago, Bricriu said:

Is the easterly phase of the QBO aiding us this year somewhat.? Would these warmings that are falling short of a major ssw not be enough if it was in a westerly phase?

In my view, this is a very big factor. Specifically the ENSO state and E-QBO together.

[stodge]

Just noting on the GFS 12Z another strong warming at the end of FI but centred on Europe and western Russia rather on Siberia.

I don't like Siberian warmings as they can knock the PV back towards Canada/Greenland but a European warming is very different.

Any thoughts?

[DavidS]

Days 11-16 on the 00z GFS