Stratosphere and Polar Vortex Watch 2020

[TSNWK]

13 minutes ago, SqueakheartLW said:

GFS 06z continues the theme of a displaced vortex around the 5th/6th January and also continues its idea of another warming taking place around the 10th/11th January. Here is the latest selection of new warming options from the 06z runs

06z GFS Operational Run                      06z GFS Control Run                             06z GFS Member 1

06z GFS Member 3                                 06z GFS Member 5                                06z GFS Member 7

06z GFS Member 8                                06z GFS Member 10                              06z GFS Member 11

06z GFS Member 12                               06z GFS Member 13                              06z GFS Member 14

06z GFS Member 15                              06z GFS Member 16                               06z GFS Member 18

06z GFS Member 19                              06z GFS Member 20                              06z GFS Member 22

06z GFS Member 23                              06z GFS Member 24                                06z GFS Member 25

06z GFS Member 26                               06z GFS Member 27                              06z GFS Member 30

Yet again just like with the 00z there are 24 out of 32 runs going for this new warming event. What is even better is that both of the higher resolution Operational and Control runs feature it too

Still maintaining this 75% chance of another warming around the 10th or 11th January. Lets see if this starts to come closer than the 350+ hours timeframe

1st post in this thread for me.. be gentle  looking at the above all I’m seeing is a displacement of the vortex to our side and to north west.. surely this is not what we want.. and might explain the loss of Greenland heights from next weekend..

[phil nw.]

Yes some of the recent gfs op. runs not fully behind a split more a displacement.However the gefs set look very promising for zw speeds heading towards reversal.

ECM Graph shows wave action still ongoing.

A split or not it seems unlikely we will see any return to our normal Winter NH pattern for sometime.

 

Edited December 26, 2020 by phil nw.

[snowking]

2 hours ago, bluearmy said:

Yes, too much Sherry for kris yesterday .......

Port mate, I’m a classy weather nerd...

Yes absolutely right @s4lancia thanks for spotting 

[SqueakheartLW]

22 minutes ago, TSNWK said:

1st post in this thread for me.. be gentle  looking at the above all I’m seeing is a displacement of the vortex to our side and to north west.. surely this is not what we want.. and might explain the loss of Greenland heights from next weekend..

Maybe it could work in our favour yet. If the vortex sets up mid Atlantic for example it could be the route to a beasterly with WWA pushing into the pole and setting up a Scandi high in the process and pushing Siberian air through Europe towards us

[Mike Poole]

Spot the difference (GFS v parallel 6z T240):

Noting that one of the major changes in the parallel is much increased vertical resolution, I’m inclined to side with the parallel, along with ECM, of course.  Can’t see the heights on the parallel, but you’d guess a SSW around 5th Jan is entirely possible.

[Mucka]

12z 384 "ongoing"

[bluearmy]

Ecm and gfsp together with gem on the same page with 10hpa temps   - the op looks like it reverses again and begins to split  again ..

and ec is split/ting  at 30/50 hpa at day 10 too 

 

 

one assumes gfs isn’t seeing something high up and as such, surely the gfs and gefs strat forecasts can have a big question mark against them at the moment .....

Edited December 26, 2020 by bluearmy

[Bullseye]

11 minutes ago, bluearmy said:

Ecm and gfsp together with gem on the same page with 10hpa temps   - the op looks like it reverses again and begins to split  again ..

and ec is split/ting  at 30/50 hpa at day 10 too 

 

 

one assumes gfs isn’t seeing something high up and as such, surely the gfs and gefs strat forecasts can have a big question mark against them at the moment .....

JMA also follows and would be grouped in same category as ECM/GFSp/GEM.

Eric Webb over the  twitter world is adamant this will be a warming resulting in displacement (initially at least). 

Edited December 26, 2020 by Bullseye
Grammar

[Mike Poole]

Just now, Bullseye said:

JMA also follows and would be grouped in same category at ECM/GFSp/GEM.

Eric Webb over the  twitter world is adamant this will be a warming resulting in displacement (intially at least). 

I think there will be a full split.  I’m discounting the old GFS, and am making the assumption that the reason it can’t see what is going on is because it coming down from the very top (1hPa) and it doesn’t have enough vertical resolution, I think we have seen enough model runs of this to be able to bet on a form horse,  a split that looks (on the 10hPa temperatures) a bit like this:

[Bullseye]

16 minutes ago, Mike Poole said:

I think there will be a full split.  I’m discounting the old GFS, and am making the assumption that the reason it can’t see what is going on is because it coming down from the very top (1hPa) and it doesn’t have enough vertical resolution, I think we have seen enough model runs of this to be able to bet on a form horse,  a split that looks (on the 10hPa temperatures) a bit like this:

There is also the consistent element to it - I feel the above models which have hinted towards split have been consistent whereas the GFS initially had split before going for displacement. Odds against GFS here but can't rule out. 

There has been a great post over on US forum today on type of warming being indicated (Siberian warming) and how this can look following SSW. Link is here to check out. Relates to research carried out by Ventrice last year. 

Met Winter 20-21: Pattern Drivers & Evolution - Page 127 - Weather Discussion - 33andrain Weather Discussion Community

WWW.33ANDRAIN.COM

 

[snowking]

4 minutes ago, Mike Poole said:

I think there will be a full split.  I’m discounting the old GFS, and am making the assumption that the reason it can’t see what is going on is because it coming down from the very top (1hPa) and it doesn’t have enough vertical resolution, I think we have seen enough model runs of this to be able to bet on a form horse,  a split that looks (on the 10hPa temperatures) a bit like this:

I am inclined to agree. I think Eric is largely referring to how you define the SSW (as k=1 or k=2) at the point of reversal - but this one looks primed to split after the initial displacement 

[SqueakheartLW]

GFS 12z maintains the form book for another warming around 10th or 11th of January

Here are all of the ensemble members that have some form of new warming to varying degrees

GFS 12z Operational                              GFS 12z Control                                     GFS 12z Member 1

GFS 12z Member 3                                GFS 12z Member 4                                 GFS 12z Member 5

GFS 12z Member 7                                GFS 12z Member 8                                   GFS 12z Member 10

GFS 12z Member 11                              GFS 12z Member 12                              GFS 12z Member 15

GFS 12z Member 16                              GFS 12z Member 17                               GFS 12z Member 18

GFS 12z Member 19                              GFS 12z Member 20                              GFS 12z Member 21

GFS 12z Member 22                              GFS 12z Member 23                               GFS 12z Member 24

GFS 12z Member 25                              GFS 12z Member 26                              GFS 12z Member 27

GFS 12z Member 28                              GFS 12z Member 29                              GFS 12z Member 30

Yet again a big majority showing another warming event

GFS 00z was 24 out of 32 or 75%

GFS 06z was 24 out of 32 or 75%

GFS 12z is 27 out of 32 or 84%

It would seem the chances of this new warming are gaining ground with the GFS increasing the number of ensembles showing it. Maybe some of the other models may pick up on this next warming if it gets into the 10 day range

[Scott Ingham]

We surely have to go with the split scenario that ECM/GFSp forecast over GFS when they have better resolution higher up?

How can the GFS be correct?

[ICE COLD]

1 minute ago, Scott Ingham said:

We surely have to go with the split scenario that ECM/GFSp forecast over GFS when they have better resolution higher up?

How can the GFS be correct?

You would of thought so . I’m in no way clued up on any of this but from watching for years the ECM always seems to be ahead in the strat . I think everyone would be surprised if it doesn’t end up the ECM way . 

[Uncertainty]

54 minutes ago, bluearmy said:

Ecm and gfsp together with gem on the same page with 10hpa temps   - the op looks like it reverses again and begins to split  again ..

and ec is split/ting  at 30/50 hpa at day 10 too 

 

 

one assumes gfs isn’t seeing something high up and as such, surely the gfs and gefs strat forecasts can have a big question mark against them at the moment .....

I’ve been thinking this for a while BA we would dismiss it (the present gfs) in the trop if it was up against ECM/JMA and an apparently better version of itself. Though as @SqueakheartLWpoints out, many GEFS have a warming rebound anyway. Would much rather the Split now though personally.

The GFS also lacks the amplification In the trop over the exact area (Greenland corridor) that the other models have. Coincidental? I’m not so sure...

Anyone know if the GEPS are still in for the split?

[Singularity]

It will be interesting to see what kind of response we get from this wave-1 dominated polar vortex split.

The one in Jan 2019 didn't propagate down much at all, but that one had hardly any wave-2 involved and the vortex seemed to just shear apart into three (one very small) due to the immense size and intensity of the warming (the vertical heat flux broke records).

This time all but GFS/GEFS are showing more of a pincer movement on the vortex, with the Atlantic side warming moving poleward and at least partially merging with the Pacific side warming within an over-pole anticyclone. So, it feels more akin to the wave-2 dominated splits of 2018 and 2013, to name a couple.

The importance of the response type is a matter of both speed and duration. A quick summary as I currently understand it:

Displacement events via wave-1 tend to propagate down slowly to the troposphere in a 'dripping paint' fashion that can be unreliable as well (as we saw, painfully much, in 2019). Impacts then last 1-4 weeks (varies between individual events + depending on which literature you read).

The negative NAM (i.e. AO) from a genuine split event usually propagates down faster, sometimes very fast, typically reaching the troposphere within a week or two. Main impact period is then 3-6 weeks. If the SSW is late enough in the year, impacts can last longer, as the polar vortex is unable to recover - March 2013 being an strong example of that (SSW was in Jan).

[georgiedre]

This sounds very very good

[Duane S.]

Wave 1 appears to have done enough damage for a moderate wave2 to do the job?

 

Heading down nicely this morning. Still just  a technical SSW at this stage but just look at h strength of the reversal coming from the top!

 

Poleward flux looks good to keep the pressure on

GFS goes for a huge reversal at both 65N and 60

A strong vortex has never really managed to get going this year. There are no real signs that it will any time soon either.

[iceman1991]

46 minutes ago, s4lancia said:

Wave 1 appears to have done enough damage for a moderate wave2 to do the job?

 

Heading down nicely this morning. Still just  a technical SSW at this stage but just look at h strength of the reversal coming from the top!

 

Poleward flux looks good to keep the pressure on

GFS goes for a huge reversal at both 65N and 60

A strong vortex has never really managed to get going this year. There are no real signs that it will any time soon either.

When will we likely start to see the effects of this ? 

[chionomaniac]

The upcomimg strat disturbance is a primary wave 1 displacement. Whether this is enough to cross the line by itself to create a SSW in itself remains to be seen. The secondary wave two is just as important in my opinion, because the stronger this can split and propagate will determine the exact trop response. And it’s too early still to make that call. 

Wave 1 responses generally will be Pacific based, no use over here, so that wave two is critical to bring the Atlantic sector back into play. The GFS is to be commended for reliably forecasting the strong wave one right from far FI, but adding in the right amount of wave two activity is where reliability reduces 

[bluearmy]

the size of reversal around 65/75 sees pretty large as it drops.  Gfs eventually generates wave 2 to split the spv and this comes up from beneath as 50 hpa shows a split ahead of the layers above ........ 

ec seems difficult to pin down re that direction of split. I only have 10/30/50 views so perhaps someone can look at Berlin and check if the split is working up or down. Looks pretty instantaneous at the levels I can see at day 8/9. 

if we do see a split, we can’t be sure yet where it will manifest and where the northern blocking may establish as consequence 

[ArHu3]

Most ec members only show displacement unfortunately although op still goes for a split

 

 

 

 

[SqueakheartLW]

My latest update

GFS

Looked through the GFS 00z and its ensembles. They are still very much on track for this extra warming event around the 10th or 11th January with a new high of 28 of 32 options having another warming showing. My favourite one by far is GFS 00z Member 25

The initial warming just displaces the vortex but then around the 10th a Siberian warming takes place and combines with yet another warming coming in from the USA side. This pulls the vortex apart completely and leaves one cold area near Europe and the other near the NE Pacific

GFS Parallel

GFS parallel has still looked more odds on for a vortex split event from the first main warming event and today still shows this taking place by 192 hours

However the vortex reforms as one mass again soon after but even the parallel run is now showing the new warming event around the 10th or 11th January too now

JMA

JMA still going for the vortex split by 192 hours

However it does reform the vortex by the end of the run but in a weakened state

GEM

The GEM is still on for a split too

So far 3 of the 4 models in favour of split over 1 with displacement. Lets see what my daily ECM analysis throws up today

ECM

Looks like a decent reversal there at most stratospheric levels by day 10. That tropical jet is going to get a bit of a boost with the increasing zonal winds above 30N to compensate for the loss of them further north. Look how little there is showing of the polar jet. Just that flabby area of 10m/s at most and even this is displaced north of the usual position

Looks like the 10hpa split option is still on with ECM so overall 4 out of 5 going for split with GFS the only one going for displacement

My latest set of data clearly shows up the predicted reversal in zonal winds at 60N and it appears to be a top down event as the reversal starts at 1hpa and appears to head down through the layers and gets down as far as 10hpa but no doubt will be showing up at 20hpa tomorrow by day 10

[Vikos]

On 21/12/2020 at 11:26, Vikos said:

 

 

We need this blue area like this

 

 

Well, EC did what I told them to do!

 

Let's ride that "mild" wave for a couple of days more, mid Jan will be big time

Edited December 27, 2020 by Vikos

[Duane S.]

5 hours ago, iceman1991 said:

When will we likely start to see the effects of this ? 

Probably around about the middle of next month. Maybe quicker. Maybe longer. Details of which, very much yet to be confirmed.