Stratosphere and Polar Vortex Watch 2020

[SqueakheartLW]

Since it has been a few days I thought I would do another daily comparison snapshot of the vortex and how it compares to the other years on the record. The latest data for the 19th Feb 2022 is below.

Daily Figure

The latest daily 10hpa 60N zonal wind speed is still quite some way above the average and on this day stands at 43.6 m/s which is +21.439 m/s above the long term mean for 19th February and this puts up 6th on the daily list for today. This continues the general trend we have seen really the entire winter so far. Since there's no sign of any SSW then it seems above average figures are very much likely to continue for the foreseeable.

On this day 2020 comes out top and this is no surprise as the polar vortex of doom was in full swing by this time. 5 years were in reversal on this day. 1987, 2010 and 2009 were only weak reversals and were either just starting or ending a SSW. 2001 was seeing a modest reversal at this time and 2018 was seeing a more significant SSW and reversal at this stage and was the precursor to the beast from the east.

Rolling Figure

The latest rolling 10hpa 60N zonal wind speed which is the rolling average from 1st November through to 19th February for 2022 stands at an impressive 41.987 m/s which is +11.462 m/s above the expected rolling mean by this stage of the season and puts 2022 into 3rd position overall and the 3rd strongest vortex year on the record so far. This continues the general upwards trend in positions. 2022 has climbed from 11th position on 18th January to 3rd by 19th February and has steadily closed the gap to 2016 throughout when the gap was 9.019 m/s on 18th January and now on the latest 19th February it has closed down to just 3.52 m/s. We are threatening to have the overall strongest vortex year on the record if we don't see things slow down soon.

As mentioned already 2016 is still in top spot by 19th February with a rolling figure of 45.507 m/s with only 1989 on 44.134 m/s now between 2022 and 2016. 2006 and 2019 remain bottom of the table with their respective weak vortex seasons averaging out at a measly 18.125 m/s for 2019 and 15.414 m/s for 2006.

[stodge]

Maybe something, probably nothing but I've not often seen a warming originating from the Canadian/Greenland side of the fence. Logic suggests that might push the PV over to the Siberian side in mid March.  Very much in FI and certainly only for interest at this time.

[phil nw.]

A last look for me at the state of the stratosphere polar vortex this season i think.

This season has continued to be disappointing from the pov of any sustained attacks on the spv and the outlook into March is no different.

GFS continues to show warmings skirting the spv at 10hPa resulting in some displacement but never doing enough and it soon repositions over the pole.

A stubborn vortex which is still running very cold against norm.

This more so at mid-level.No surprise to see forecasted zonal winds remaining strong

So Winter ending with this very mobile NH pattern with no sign of a last minute warming.It is looking more and more likely we will see a Winter without a SSW and indeed the demise of the vortex will come with a final Spring warming.

Edited February 21, 2022 by phil nw.

[phil nw.]

A few off topic posts have been hidden.

Let's try and keep posts strat related please all.There are other threads if discussions drift into past Winters and other influences,

Thanks. 

Edited February 21, 2022 by phil nw.

[damianslaw]

A final Spring warming then.. will it be a gradual one that goes unnoticed or might we see something more abrupt but too late to bring any notable cold but perhaps might bring a degree of cold at least.. there are hints the core will nudge east at times to being in further polar outbreaks but retreat quickly back west in the early part of Spring. 

It's been a poor season for any interest in the stratosphere this year. Always next winter! 

 

[SqueakheartLW]

19 hours ago, damianslaw said:

A final Spring warming then.. will it be a gradual one that goes unnoticed or might we see something more abrupt but too late to bring any notable cold but perhaps might bring a degree of cold at least.. there are hints the core will nudge east at times to being in further polar outbreaks but retreat quickly back west in the early part of Spring. 

It's been a poor season for any interest in the stratosphere this year. Always next winter! 

 

Since SSW's only happen in approx. 6 winters per decade and this means 4 without then we were always due a winter without. If we take this winter and the 9 previous ones we are very much slightly behind with the 6 in 10 statistic unless we get a very late one this year before the month is out.

Winters with SSW                    Winters with no SSW

2012/13                                    2013/14

2015/16                                    2014/15

2017/18                                    2016/17 

2018/19                                    2019/20

2020/21                                    2021/22     No so far

If we end with no SSW then we are overdue one and this puts us odd on for one to definitely happen next winter 2022/23 although nothing is guaranteed of course.

[Bill4321]

I thought that this may interest some of you on this thread..

Simon’s Stratosphere Watch #1 | Simon Lee

SIMONLEEWX.COM

---

Welcome to a new blog series! Yes, the title was indeed chosen to fit the SSW acronym. In these posts, I intend to give a brief summary of the state of the Arctic stratospheric polar vortex and the latest...

 

[bluearmy]

Gfs ops are playing with what could become a reversal in week 3. 

[Mike Poole]

On 22/02/2022 at 19:26, SqueakheartLW said:

Since SSW's only happen in approx. 6 winters per decade and this means 4 without then we were always due a winter without. If we take this winter and the 9 previous ones we are very much slightly behind with the 6 in 10 statistic unless we get a very late one this year before the month is out.

Winters with SSW                    Winters with no SSW

2012/13                                    2013/14

2015/16                                    2014/15

2017/18                                    2016/17 

2018/19                                    2019/20

2020/21                                    2021/22     No so far

If we end with no SSW then we are overdue one and this puts us odd on for one to definitely happen next winter 2022/23 although nothing is guaranteed of course.

Think that’s an example of the gambler’s fallacy!

[Wheezer]

It may increase the odds, but not the chances, big difference 

[Uncertainty]

Marco’s saying it’s a split and it looks like it just about makes it to me.

Surely this isn’t a coincidence 

Heights building to the NW of the U.K. splitting the PV into two vortices at both levels.

Can anyone add anything to this? There is very little fanfare about this online. Presumably because a reversal seems unlikely and the temps don’t warm up enough to be a major ssw???

I can’t access the ECM strat charts, is it still going for a split? I’m guessing it isn’t given the op. 
 

Alternative explanation if the ecm strat profile is similar is it’s the stronger tropical signal on the GFS is driving the ridge. Maybe it’s both.

[Bill4321]

Another blog post from Simon Lee. He is well worth a follow if you're into the stratosphere and do the Twitter thing.

Simon’s Stratosphere Watch #2 | Simon Lee

SIMONLEEWX.COM

---

When I wrote the first SSW blog on the evening of Tuesday 22 February, I did not expect to be writing the next one so soon after with such increased uncertainty. But there are many aspects to the way the...

 

[bluearmy]

Two more date records fall to 2022

suspect one more tomorrow and then a steady fall to below average in a weeks time as the spv splits temporarily and the main segment relocates to the Asian side. 

Beyond next week it seems that a slow increase to average is likely 

[Mike Poole]

ECM yesterday’s 12z run, T192:

Zonal mean zonal wind 10.3 m/s at lowest so it is a way off a technical SSW with a reversal.  

Does look like a split.

GFS and GEFS mini maps at T192:

Again nowhere near a reversal, but I did find one!  GEM ensemble member 15 at T228:

That aside this disturbance in the stratosphere looks to quickly peter out.

 

 

[SqueakheartLW]

As we now have 10hpa 60N zonal wind speeds for the whole of February it is time for me to do another of my polar vortex updates today to see where we stand.

Below I have the latest daily zonal wind speed vs all other years on the record as well as the 2021/22 rolling mean vs all other rolling means from 1st November to 28th February.

Daily 10hpa 60N zonal wind speed

The zonal wind speed for 28th February 2022 comes out in a clear top spot today with a new date record of 54 m/s which is a big +34.056 m/s above the expected zonal wind speed for end of February and very much continues the theme for the 2021/22 vortex season of above average and at times record breaking strong zonal winds.

It would seem that we have unfortunately had a repeat of a polar vortex of doom season as we have remained above average really for the entire winter and only had some below average speeds back in November on my measurement period.

1999 was weakest on this day with a noticeable reversal of the zonal winds along with weaker reversals in 1989, 2018 and 2008 also.

Rolling 10hpa 60N zonal wind speed (01/11/2021 to 28/02/2022)

The rolling mean zonal wind speed up to 28/02/2022 stands at an impressively high 42.116 m/s which is +12.382 m/s above where the rolling mean should be at the end of February and this continues the upwards direction of the 2021/22 season as we have now jumped above 1989 into 2nd position on the list and with the reversal that was starting to take place in 1989 at this stage that has taken that year below the 1999/00 season as well which now moves up to just behind this season.

Still 2016 reigns supreme at the top of the list but with March also a part of my measurement period and with a very early final warming taking place in March 2016 then unless we see a dramatic and sustained reduction in zonal winds speeds during March 2022 to much closer to average or even below average then it is now looking very likely that the 2021/22 vortex season could end up finishing as the strongest one on the record.

Perhaps this brief drop in zonal winds in the next few days could just prove enough to prevent 2021/22 going down as the strongest vortex on the record although with the way 2019/20 performed it could come steaming through and beat this year but we have had a bit more of a head start this year compared with 2019/20 and it could just be the earlier stronger vortex this year that finally sees the strongest overall season vortex record fall.

[bluearmy]

ec46 will be of interest later to see if it drops the spv off significantly again post this current return to ‘average’

todays gfs op has a tech ssw day 13 

[topo]

[bluearmy]

16 hours ago, topo said:

The momentum for a drop well below average (and possibly a reversal)  beyond the approaching rebound is growing …..

[phil nw.]

3 hours ago, bluearmy said:

The momentum for a drop well below average (and possibly a reversal)  beyond the approaching rebound is growing …..

,,.and probably the final demise of this season's Spv.

[stodge]

Afternoon all

I don't have the knowledge of the SPV others bring to this so just my observations off the models.

Unfortunately, the PV remains too powerful and the zonal wind too strong to allow proper amplification into Scandinavia in the short term so we missed an early March cold wave as the HLB has become an MLB (the cold wave has gone south to affect, unfortunately, the Ukraine).

The medium to longer term modelling continues to show strong heights to the east and we go into the second half of the month increasing signs of this amplification building slowly westward towards the Baltic. That means LP systems coming in from the west aren't able to move through to the east of the British Isles and either swing strongly north or disrupt over or just to the west of the British Isles.

As the zonal wind speed decreases and the PV comes under continued Wave 1 warming (something strangely absent in the depth of this past winter), the opportunities for this amplification westward continue and I'm now increasingly of the view we will see strong northern blocking in April (nothing unusual in that of course) centred over Scandinavia and a prolonged period of winds sourced from the east.

The other interesting development is or are the consequent draining of heights from Europe - part of which is the trough disruption mentioned above which leaves energy to move SE into Europe and even link with instability moving up from North Africa to create a weak but general LP area over much of Europe to support the heights to the north and east.

Moving this on into real speculation, I just wonder if this spell of northern blocking is setting us up for a classic "European monsoon" in May/June with frequent incursions of warm but thundery and unstable air from the south. 

[SqueakheartLW]

I thought it was time for me to do my latest polar vortex update today and I particularly wanted to do it after what the data showed when I updated my daily readings for the overall zonal wind strength for this season for the November to March period and you'll see the significance today with the rolling mean.

Here I present you with the latest data for the 10th March which is the latest figures I have

Daily 10hpa 60N zonal wind speed for 10/03/2022

The figure for 10/03/2022 comes in above average which has generally been the story of the season so far although we have just had a brief dip in the wind speeds. The daily figure is 31.2 m/s which is +13.393 m/s above the expected zonal wind speed for the 10th March and that puts 2022 in 7th position today on daily zonal wind speeds.

2019 was in top spot on this date with 2020 not far behind it and both were significantly faster with zonal winds than this year is.

4 years saw a reversal of zonal winds on this day. 1984 with a very minor reversal of -1.86 m/s with 1989 another minor reversal of -3.64 m/s. These two are rather weak compared with the bottom 2 in the list. 1999 was 2nd to bottom with a more significant -14.31 m/s reversal but 2016 was the biggest one of them all at a staggering -23.19 m/s (-40.997 m/s below normal).

Rolling 10hpa 60N zonal wind speed for the 01/11/2021 to 10/03/2022 period

Now for the significant one for today, the rolling 10hpa 60N zonal wind speed. The figure for 2022 comes in at 40.752 m/s which is +11.887 m/s above the expected rolling mean but what makes that figure significant is that it places 2022 in top spot for the first time this season, finally knocking 2016 off top spot which it has held for most of the season.

2022 may not stay top for very long however as if the forecasts come off then 2022 is going to soon see a big drop in zonal winds, a bit like what 2016 did but maybe not as big a drop as it saw whilst 2020 which has been steadily climbing up the order too has been closing the gap to 2022 down for quite some time now. The gap between 2022 and 2020 was 3.176 m/s on 07/02/2022 and on the latest rolling mean for 10/03/2022 the gap has closed down to just 0.417 m/s.

In 2020 the vortex carried on for some while longer whilst the forecasts for 2022 are for a brief stronger period before the vortex looks to collapse completely next week which could mean that despite the above average season we have had that 2022 could be saved from ending as the strongest on the record by the time the end of my measurement period which will be 1st November to 31st March is over.

[bluearmy]

On 24/02/2022 at 13:45, bluearmy said:

Gfs ops are playing with what could become a reversal in week 3. 

Gfs and ec both now showing a split ssw around day 7/8 …

 

[Kirkcaldy Weather]

2 minutes ago, bluearmy said:

Gfs and ec both now showing a split ssw around day 7/8 …

 

I've not been looking at the strat charts but did see this tweet earlier 

 

[Don]

4 minutes ago, bluearmy said:

Gfs and ec both now showing a split ssw around day 7/8 …

 

Two months too late, but there you are!

[bluearmy]

1 hour ago, Don said:

Two months too late, but there you are!

Known as the law of sod ……