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

[Andy8472]

Defo disturbed weaker core, interesting!

[Mike Poole]

If anyone can explain why ECMWF and UKMO seasonal models (December updates) are so completely at odds with this forecast, I’d like to hear why!  The charts show probability of net easterly winds at 10hPa 60N compared to climatology.  

 

[Mike Poole]

Actually, I can go some way to answering my own question, looking at the zonal winds, believe it or not, GloSea6 has completely missed the Canadian warming in week 1 of the simulation!

Highlighted difference on ECM chart.

[bluearmy]

as expected,that pgfs 06z op reversed to about 70N 

 

Edited December 10, 2023 by bluearmy

[bluearmy]

4 minutes ago, Mike Poole said:

Actually, I can go some way to answering my own question, looking at the zonal winds, believe it or not, GloSea6 has completely missed the Canadian warming in week 1 of the simulation!

Highlighted difference on ECM chart.

Well not quite completely Mike but clearly it’s awry first half dec so you’d have to question it’s subsequent output 

[Andy8472]

Be kind of funny if the DWD ended up being right with the Ecm not far behind

[Mike Poole]

13 minutes ago, bluearmy said:

Well not quite completely Mike but clearly it’s awry first half dec so you’d have to question it’s subsequent output 

Yes, a few realisations have it, I guess.  Do you know if GloSea6 accumulates its runs a few per day in the lead up to the release date?  The Canadian warming cropped up very suddenly, so if most of the realisations were run earlier in November, that might explain it.

10 minutes ago, Andy8472 said:

Be kind of funny if the DWD ended up being right with the Ecm not far behind

Yes, the German model goes very much the other way.  And to be fair, given the warmings starting to show on GEFS, it might have a point!

[Andy8472]

6 minutes ago, Mike Poole said:

Yes, a few realisations have it, I guess.  Do you know if GloSea6 accumulates its runs a few per day in the lead up to the release date?  The Canadian warming cropped up very suddenly, so if most of the realisations were run earlier in November, that might explain it.

Yes, the German model goes very much the other way.  And to be fair, given the warmings starting to show on GEFS, it might have a point!

We can only hope 

Core weak again but missing the warming 

Edited December 10, 2023 by Andy8472

[bluearmy]

29 minutes ago, Andy8472 said:

We can only hope 

Core weak again but missing the warming 

Anomalies other side of the pole are high and will mean the spv is displaced over the Russian side 

looks pretty similar to the 06z and yesterdays 18z. Definitely a trend from the gfs ops 

[Andy8472]

Just now, bluearmy said:

Anomalies other side of the pole are high and will mean the spv is displaced over the Russian side 

looks pretty similar to the 06z and yesterdays 18z. Definitely a trend from the gfs ops 

Yes & the op got down to the lowest yet 5m/s!

[bluearmy]

1 minute ago, Andy8472 said:

Yes & the op got down to the lowest yet 5m/s!

Getting closer 

be good to see the strat weak flow heading down as the 06z run showed

 

[bluearmy]

Ec op day 10 looks closer to gefs than gfs (which probably means gfs is too progressive) 

[Andy8472]

Tidbits version

[Premiere Neige]

15 minutes ago, Andy8472 said:

Tidbits version

How far up the scale does the deepest red on that warming go please? (I'm colour blind and struggle big time with reds). Cheers!

[Andy8472]

5 minutes ago, Premiere Neige said:

How far up the scale does the deepest red on that warming go please? (I'm colour blind and struggle big time with reds). Cheers!

-22/24

[SqueakheartLW]

GFS looks to be odds on for this warming at the end of its ensembles at present but I can't say the same for the GEM although it has some interest in another way

Here's the 4 best GFS 12z warmings

+4C

+8C

These are at the warmest end but the main warmings appeared to peak more around -12C on the 12z

 The GEM has NO warmings showing at all but what is interesting on the GEM 12z is the number of ensemble members that are really stretching out the cold temperatures at the back end of the runs. I have included the 4 best ones below

There were several more members doing something similar but slightly colder than these ones. These look close to splitting the vortex despite no actual warming showing up.

[Premiere Neige]

7 minutes ago, Andy8472 said:

-22/24

Cheers mate!

[Premiere Neige]

5 minutes ago, SqueakheartLW said:

GFS looks to be odds on for this warming at the end of its ensembles at present but I can't say the same for the GEM although it has some interest in another way

Here's the 4 best GFS 12z warmings

+4C

+8C

These are at the warmest end but the main warmings appeared to peak more around -12C on the 12z

 The GEM has NO warmings showing at all but what is interesting on the GEM 12z is the number of ensemble members that are really stretching out the cold temperatures at the back end of the runs. I have included the 4 best ones below

There were several more members doing something similar but slightly colder than these ones. These look close to splitting the vortex despite no actual warming showing up.

The GEM is a weird one. Like it's being displaced without anything really to displaced it!

[Andy8472]

2 minutes ago, Premiere Neige said:

The GEM is a weird one. Like it's being displaced without anything really to displaced it!

The Gem looks similar to the gfs op, it decays the core with 10hpa winds at low + levels 

[Andy8472]

Latest ECM 10hpa

 

Edited December 10, 2023 by Andy8472

[bluearmy]

27 minutes ago, Premiere Neige said:

The GEM is a weird one. Like it's being displaced without anything really to displaced it!

Gem isn’t very far from the eps at day 15 

gefs are different in the strength of their warming over e Asia which is up to -24c whereas gem and eps are around -44c 

all three are similar over Canada with the level of warm anomoly. 

all three have a similar displaced tpv locale 

the gfs op is v progressive in its displacement at that timescale 

[Mike Poole]

10hPa temperatures from ECM 46, last 3 runs, week beginning 18th Dec:

Week beginning 25th Dec:

Very big increase in the signal for warming these two weeks, particularly Christmas week (not sure if that is two separate warming events , and if it is whether they might be on different realisations).

Less signal late January on today’s too.  I think a likely SSW is being brought forward in time by the models and quite quickly.

[Bricriu]

So is a displacement  looking more likely than a split? If the spv were displaced to Siberia, could we still eek out a cold spell from  it?

[bluearmy]

11 hours ago, Bricriu said:

So is a displacement  looking more likely than a split? If the spv were displaced to Siberia, could we still eke out a cold spell from  it?

Atm, yes. We’d expect to see a stretching spv if we are to drive a split ssw.  If a displacement then of course better that it’s to the Asian side (which it usually is due to the n pacific ridge pushing towards the pole) 

housekeeping - at day 16 gfs op has a technical ssw at 1hpa ……… the gfs ops have been fairly consistently progressive over the past couple days on this displacement and v weak flow but this is the first reversal shown as low as 60N thus far.  We saw them yesterday below 10hpa but were close to the pole. 

[bluearmy]

7 hours ago, bluearmy said:

Atm, yes. We’d expect to see a stretching spv if we are to drive a split ssw.  If a displacement then of course better that it’s to the Asian side (which it usually is due to the n pacific ridge pushing towards the pole) 

housekeeping - at day 16 gfs op has a technical ssw at 1hpa ……… the gfs ops have been fairly consistently progressive over the past couple days on this displacement and v weak flow but this is the first reversal shown as low as 60N thus far.  We saw them yesterday below 10hpa but were close to the pole. 

And the 06z op at day 16 showed a surge of strong zonal flow around 70N at 1 hpa so that shows the problem of using operationals at that range