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

[Kirkcaldy Weather]

Excited to fire this thread up with the newly emerging SPV and rather interesting signs already emerging, I really do believe this will be a VERY exciting year with comparable years which I've been covering within my thread here

So onto the events developing in the short and mid term I noticed a bit of warming going through the 10mb height charts I thought I was being  however checking the corresponding charts its there no doubt with a wave 1 signal already coming through  

As I covered in my latest mod post this is the same time we'll see the net cycle of the MJO through the Pacific perhaps at increased amplitude I'm sure we all remember the 2018 SSW with the big preceding Pacific MJO cycle 

 

BOMM currently the most aggressive with it of course not to the degree of 2018 but nonetheless the Pacific 100% being boosted in activities. Will be exciting seeing which models are handling strat events best but look at this 

EC gets a few reversals by November week 1 

[Kirkcaldy Weather]

 

 

[Mike Poole]

A period of strong vortex intensification has come out of nowhere on the ECM 46 in the last few days:

Centred about the 22nd October, most realisations now go well outside of the 90th percentile on the zonal winds.  It just wasn’t showing 5 days ago.  

So while some of the seasonal models were showing the vortex getting off to a slow start in their September update, that seems rather scotched now if this signal the ECM 46 has latched onto is right.

I would not expect this to affect the weather down here as of yet, as it is unlikely to be coupled to things in the troposphere right now.  

Whether this means anything for winter?  1-0 to the vortex, or does this mean that there is something there to properly blow apart if disturbances come early season?  Time will tell…

 

[Rain All Night]

I've only been here for one year, but not having to wait three or four days between extended range ECM ensemble runs must feel like the end of an era for some of you?!

[Kirkcaldy Weather]

VERY Interesting GFS Operational we begin with an initial warming zone through Europe at the start of the upcoming week then the Scandi High pressure Retrogression, Next  as the Greenland High links with the increasing high pressure over Alaska seems to enhance the warming with the split signal emerging 

 

[Mike Poole]

With two of the seasonal models (UKMO GloSea6 and DWD) suggesting the possibility of a November SSW in their latest updates, it is worth a look at the only 2 occasions when this has happened since records began, 30 Nov 1958 and 28 Nov 1968.

Interestingly, these were both El Niño and east QBO years.

I can only find plots of 10 hPa temperature, here’s 1958 along with the trop pattern:

The trop pattern 3 weeks earlier showed an Atlantic ridge:

Blocking in scandi also figured in the lead up.

1968:

And 3 weeks earlier:

This is the more interesting one, because it does not look dissimilar in terms of the block location and location of the trop vortex to what the GFS is turning out in about 10 days time…

Edited October 12, 2023 by Mike Poole

[Cheshire Freeze]

14 minutes ago, Mike Poole said:

With two of the seasonal models (UKMO GloSea6 and DWD) suggesting the possibility of a November SSW in their latest updates, it is worth a look at the only 2 occasions when this has happened since records began, 30 Nov 1958 and 28 Nov 1968.

Interestingly, these were both El Niño and east QBO years.

I can only find plots of 10 hPa temperature, here’s 1958 along with the trop pattern:

The trop pattern 3 weeks earlier showed an Atlantic ridge:

Blocking in scandi also figured in the lead up.

1968:

And 3 weeks earlier:

This is the more interesting one, because it does not look dissimilar in terms of the block location and location of the trop vortex to what the GFS is turning out in about 10 days time…

1968 SSW led to some interesting trop patterns later on in December-

[Rain All Night]

32 minutes ago, Mike Poole said:

With two of the seasonal models (UKMO GloSea6 and DWD) suggesting the possibility of a November SSW in their latest updates, it is worth a look at the only 2 occasions when this has happened since records began, 30 Nov 1958 and 28 Nov 1968.

Interestingly, these were both El Niño and east QBO years.

I can only find plots of 10 hPa temperature, here’s 1958 along with the trop pattern:

The trop pattern 3 weeks earlier showed an Atlantic ridge:

Blocking in scandi also figured in the lead up.

1968:

And 3 weeks earlier:

This is the more interesting one, because it does not look dissimilar in terms of the block location and location of the trop vortex to what the GFS is turning out in about 10 days time…

I assume that since these SSWs were so early, the SPV had plenty of time afterwards to recover to full strength and see out the remainder of the winter?

[Mike Poole]

9 minutes ago, RainAllNight said:

I assume that since these SSWs were so early, the SPV had plenty of time afterwards to recover to full strength and see out the remainder of the winter?

Going by the charts, the trop vortex looks disturbed throughout winter 68/69, 58/59 doesn’t look very out of the ordinary to be honest.

The strat vortex certainly can recover after a SSW, but I guess other drivers will determine how much pressure it is then put under subsequently.  

[Kirkcaldy Weather]

1 hour ago, Mike Poole said:

With two of the seasonal models (UKMO GloSea6 and DWD) suggesting the possibility of a November SSW in their latest updates, it is worth a look at the only 2 occasions when this has happened since records began, 30 Nov 1958 and 28 Nov 1968.

Interestingly, these were both El Niño and east QBO years.

I can only find plots of 10 hPa temperature, here’s 1958 along with the trop pattern:

The trop pattern 3 weeks earlier showed an Atlantic ridge:

Blocking in scandi also figured in the lead up.

1968:

And 3 weeks earlier:

This is the more interesting one, because it does not look dissimilar in terms of the block location and location of the trop vortex to what the GFS is turning out in about 10 days time…

 

On 23/09/2023 at 22:59, Kirkcaldy Weather said:

Kirkcaldy Weathers Official 2023 >>> 2024 Winter Outlook

I'll be conducting this in separate sections which cover the most significant phenomena contributions into winter 2023/2024.

Section 1

ENSO WITH QBO + STRATOSPHERIC WARMING RELATIONSHIPS

Perfect timing as an updated and cleaner laid out format containing excellent info which factors in the above categories has been made by Amy Butler 

• 2023 has seen an increasing El Nino with major similar strength and peak C and time of peak as the 2009 event which rose to +1.7C and peak was around October and November
• The key combos for this coming winter then is Nino plus EQBO

Lets start with the years which contained the same formation as this coming winter Nino and EQBO WHICH FEATURED A SSW

1958/1959

DEC 

 

JANUARY

FEBRUARY

1965/66

This is a fascinating year listed as having dual SSW 

 

DEC 1965 8-Dec-65 16-Dec-65 18-Dec-65 16-Dec-65EE

FEB 1966 24-Feb-66 23-Feb-66 23-Feb-66 22-Feb-66EE

December

January

February

 

1968,69

 

December

jan

Feb

1968 (December):

One of the few 'WHITE CHRISTMASES' of the 20th century; heavy overnight SNOW in the Midlands and Wales had stopped by first light on Christmas morning, leaving a blanket of snow over a foot deep in the Welsh Marches and almost as much in the Cotswolds. SNOW was also reported further south. [ See my Christmas holiday files elsewhere on this site. ]

 1968/69 (Winter):

A notably COLD spell across the Denmark Strait / Iceland region (ICE reached north & east coastal Iceland by late winter - not known in recent/early 21st century years), coincided with the 'Cod War' between Iceland and the UK, when Iceland attempted to protect their fishing grounds from UK trawlers. Several British trawlers capsized due to superstructure ICING - which made the small ships unstable. A trawler support vessel [MV 'Miranda'] was stationed in the area, funded by the UK government, with an on-board meteorologist. [ At the time I was an Assistant in the Central Forecast Office, Bracknell - we had to plot special charts to support the forecasts for the fishing fleet and the Miranda. ]

 1969 (February):

On 7th February, 1969 the highest GUST (up to that time, beaten in 1989) at a low level station in Great Britain was recorded at Kirkwall in the Orkney's, 118 knots.
SEVERE BLIZZARD across the northern Isles, as a polar low slipping southeast across Britain on the 7th gave rise to exceptionally severe, near BLIZZARD conditions across the Midlands and East Anglia, along with parts of southern England.
On the 19th, south Devon was hit by a SEVERE GALE (easterly), causing considerable DAMAGE; at the same time, there was a good deal of DRIFTING SNOW over southern Britain.

1972 -- 1973

 

The Massive South Carolina Blizzard Of February 1973 Will Never Be Forgotten

WWW.ONLYINYOURSTATE.COM

---

The Blizzard of 1973 wreaked havoc on South Carolina's roadways and structures, causing untold millions in damage.

 

Dec

January

february

JAN 1977****9-Jan-77 9-Jan-77 9-Jan-77 EE

Dec 1976

January 1977

February 1977

1979/80

Dec 

January

FEB

FEB 1980 29-Feb-80 29-Feb-80 29-Feb-80 29-Feb-80 29-Feb-80 29-Feb-80EE

Didnt get round to covering it but it was an anomaly really how it developed - recent East QBO and nino in the Jan 2019 event, ,I think that was the warming that went up at a bit of an odd angle and the zonal westerlies didnt successfully manage to go easterly hence why there wasnt really any surface cold which followed

[Frigid]

35 minutes ago, RainAllNight said:

I assume that since these SSWs were so early, the SPV had plenty of time afterwards to recover to full strength and see out the remainder of the winter?

Not entirely. Winter 58/59 had a pretty cold January with a CET of 1.6C, but interestingly Winter 68/69 had a pretty cold February with a CET of 1.0C.. March was also pretty cold with CET's in the 3s. With the only two cases of Nov SSWs showing cold weather it's clear that if it were to happen again, then late cold wouldn't be out of the question

Edited October 12, 2023 by Frigid

[Cheshire Freeze]

I thought 1962 had a CW, was that in December?

Edit- just looked, it was January.

Interestingly 1987 had an early Dec warming.

Edited October 12, 2023 by Cheshire Freeze

[alexisj9]

8 minutes ago, Frigid said:

Not entirely. Winter 58/59 had a pretty cold January with a CET of 1.6C, but interestingly Winter 68/69 had a pretty cold February with a CET of 1.0C.. March was also pretty cold with CET's in the 3s. With the only two cases of Nov SSWs showing cold weather it's clear that if it were to happen again, then late cold wouldn't be out of the question

Don't mind as long as it's not still cool in may again.

Edited October 12, 2023 by alexisj9

[Catacol]

20 hours ago, Cheshire Freeze said:

I thought 1962 had a CW, was that in December?

Edit- just looked, it was January.

Interestingly 1987 had an early Dec warming.

There was a Canadian Warming in Nov 1962.

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

Edited October 13, 2023 by Catacol

[bluearmy]

Ec46 final week is beginning to show a warming of sorts at 10hpa exiting Asia and headed across the n pacific sector. Will it stick over the next couple of weeks and if it does, how will it evolve ? 
 

[Mike Poole]

Just keeping my eye on the zonal winds on the daily ECM 46 runs.

Latest:

One week earlier:

The latest run has 7/100 reversals by end November.  Maybe the same signal GloSea6 was picking up on?  (Climatology is about 2/75, so a slightly increased signal).

This model picked up on the vortex intensification next week, but it is what happens after that I’m interested in.

[Jacob]

1 hour ago, Mike Poole said:

Just keeping my eye on the zonal winds on the daily ECM 46 runs.

Latest:

One week earlier:

The latest run has 7/100 reversals by end November.  Maybe the same signal GloSea6 was picking up on?  (Climatology is about 2/75, so a slightly increased signal).

This model picked up on the vortex intensification next week, but it is what happens after that I’m interested in.

A couple members appear to be going for an SSW, not many but it does raise the possibility

[MattH]

As usual, it isn't just about the vortex strength at 10hPa it is about how its behaviour and influence progress down through the strat and into the trop as the next few months progress which are always important. If you get that late Nov/early Dec connection between the strat and the trop, whereby zonal, W'ly winds have downwelled into the trop then as is often the case the first half of December, if not more can soon be written off in terms of anything wintry. That is often the standard progression across the N Hem through late Nov and into Dec and it takes some other 'external factor' like a pronounced MJO event, for example, to create a different outcome, at least for a time.

The key thing this season to look for though is a clearly disorganised sPV and one that has little or no significant impacts on the trop given the eQBO and Nino combination. The caveat here is potentially other variables within the troposphere that could be an overriding factor, like the +ve IOD event, while some are talking about the high amounts of H20 within the strat after the Hunga-Tonga volcano from well over a year ago potentially aiding to cool the strat and intensify the vortex. There is some science behind this as this is how the vortex develops in the first place, but no one really knows how much (or not) of an influence this will be.

As ever each season is slightly different from the last, but we go into this winter season with the long-awaited, entrenched eQBO and Nino combination and while a November SSW is extremely unlikely, one would be expected at some point this winter. However, the key point here is that it's not just what the vortex is doing up at 10hPa, etc, it's how it's influencing conditions in the trop that is equally, if not more important. At the moment there is a clear disconnect expected looking ahead, but not surprising for now given the time of year...

Cheers, Matt.

Edited October 18, 2023 by MattH

[bluearmy]

ec46 first look at the beginning of December at 10 hpa 

[Rain All Night]

What are the chances that the surge in 10hPa vortex activity that's currently underway will be reflected in some way down here in the troposphere within the next few weeks?

[bluearmy]

8 hours ago, RainAllNight said:

What are the chances that the surge in 10hPa vortex activity that's currently underway will be reflected in some way down here in the troposphere within the next few weeks?

No sign of it doing so on the ec46 November output with plenty of high anoms over the Arctic field. We may end up having a fairly unsettled November with the fairly weak jet further south than might be expected 

as Matt references above, coupling not occurring as yet. 

 

[bryan629]

GFS is modelling a split in around 10 days! 

is this normal for the time of year? 

[Mike Poole]

14 minutes ago, bryan629 said:

GFS is modelling a split in around 10 days! 

is this normal for the time of year? 

GFS is modelling a pair of pants, I’ll give you that!

It is a split from the trop upwards, by the look of it, but it does extend right up to 10 hPa at T288:

Perhaps highlights the disconnect between the developing vortex at the top of the strat and what is going on down in the trop at the moment, which is quite unusual for the time of year, the trop vortex is all over the place.

[Catacol]

The Nov forecast for a strong Russian/Ural High is firming up. Watch the vortex come under some early pressure. And then JMA produces this for December

This is a very good setup for ongoing stress. That Russian/Ural ridge is still in place and the north pacific has a distinct low pressure signal - suggesting trough influence could extend over the Aleutians. With AAM rising, Nino beginning to take hold and a signal for stratospheric stress in the early part of winter things are panning out rather well if snow chances are your thing.

I continue to see the autumn overall as wet and stormy and we certainly seem to be seeing things wind up at present. November could end up very wet indeed. But I would expect the MJO to come back around to 6/7/8 in early December setting up chances of blocking mid month. If we can bag pacific led blocking early season, with the stratosphere under pressure at the same time, then this winter may evolve into one with more cold interest than the modern average. Then again - I'm always optimistic of cold outcomes as we creep ever closer to December..

[bluearmy]

Beginning to see a trend on ec46 for many members keen to increase zonal flow fairly sharply beyond next mid month and then some quite even sharper reductions towards month end and into December. A long way off but something to watch