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

[Andy8472]

More like this please! 

[SqueakheartLW]

1 hour ago, Andy8472 said:

More like this please! 

More like these please for warming peaks

Also apart from the best one you have shown here there are a couple more on GEM that look like they are possibly headed the same way

 

[Andy8472]

Mean slightly higher today 

[Mike Poole]

2 minutes ago, Andy8472 said:

Mean slightly higher today 

The initial vortex intensification is almost unanimous now, barring a couple of stragglers.  Uncertainty remains on the other side, but solid cluster goes straight for the SSW.  

[Andy8472]

Lastest EPS 

[summer blizzard]

1 hour ago, Mike Poole said:

The initial vortex intensification is almost unanimous now, barring a couple of stragglers.  Uncertainty remains on the other side, but solid cluster goes straight for the SSW.  

Three SSW clusters in that first third, the mean avoids it but largely due to spread and the strongest SSW is probably the highest plurality. 

 

[ICE COLD]

2 hours ago, Mike Poole said:

The initial vortex intensification is almost unanimous now, barring a couple of stragglers.  Uncertainty remains on the other side, but solid cluster goes straight for the SSW.  

Hi Mike doesn’t the vortex always intensify before a ssw takes place ? I’m sure I’ve read this before ? 

[summer blizzard]

2 minutes ago, ICE COLD said:

Hi Mike doesn’t the vortex always intensify before a ssw takes place ? I’m sure I’ve read this before ? 

Most of the time but not always. It’s simply the vortex being pushed around on this occasion. 

[Mike Poole]

56 minutes ago, ICE COLD said:

Hi Mike doesn’t the vortex always intensify before a ssw takes place ? I’m sure I’ve read this before ? 

It looks quite significant this time, the vortex was very displaced from the Canadian warming, and this new warming is pushing it back over the pole.

[bluearmy]

The gfs remains bullish on rotating the spv across the pole and ends up  n Greenland as it’s pushed across the pole by the warming 

the gefs seems to be centered Barents Sea svaalbard to Novaya Zemlya 

awaiting the eps - it has been more akin to the gefs but further towards ne scandi

the gfs and ec op stand off on the speed of the warming continues. The gefs have taken a small step towards the gfs but the gap between the ops remains 4 days on that cold area in ne Siberia 

interesting to see that the reversal in the strat grows at 30N and then extends northwards - currently flushing the stronger flow towards the trop as per below. The gfs ends with a tpv centred primarily across the pole. 
 

 

EDIT

Eps updated 

The mean at day 15 looks pretty much reversal with the outside height contour on the strat low across 90N 

the model is a little ahead of the gefs in its rotational movement of the spv back towards n scandi /barents. We can see that the gefs are closer to svaalbard but as a day 15 mean it’s comparable 

the gefs are not as close to a tech ssw. Eps spv is 2920 dam whilst gefs is 2880. 
 

   

 

Edited December 22, 2023 by bluearmy

[ICE COLD]

JMA has this aswell

[Uncertainty]

1 hour ago, bluearmy said:

The gfs remains bullish on rotating the spv across the pole and ends up  n Greenland as it’s pushed across the pole by the warming 

the gefs seems to be centered Barents Sea svaalbard to Novaya Zemlya 

awaiting the eps - it has been more akin to the gefs but further towards ne scandi

the gfs and ec op stand off on the speed of the warming continues. The gefs have taken a small step towards the gfs but the gap between the ops remains 4 days on that cold area in ne Siberia 

interesting to see that the reversal in the strat grows at 30N and then extends northwards - currently flushing the stronger flow towards the trop as per below. The gfs ends with a tpv centred primarily across the pole. 
 

 

EDIT

Eps updated 

The mean at day 15 looks pretty much reversal with the outside height contour on the strat low across 90N 

the model is a little ahead of the gefs in its rotational movement of the spv back towards n scandi /barents. We can see that the gefs are closer to svaalbard but as a day 15 mean it’s comparable 

the gefs are not as close to a tech ssw. Eps spv is 2920 dam whilst gefs is 2880. 
 

   

 

Are you saying the eps are showing a mean reversal Nick? That would be quite something. And am I right in saying that the the 46 is now fundamentally a separate model and won’t necessarily follow on from the eps? 
 

Whatever the GEFS are doing on the strat isn’t stopping them producing an eye catching block in the trop mind!

[sebastiaan1973]

Just now, Uncertainty said:

Are you saying the eps are showing a mean reversal Nick? That would be quite something. And am I right in saying that the the 46 is now fundamentally a separate model and won’t necessarily follow on from the eps? 
 

Whatever the GEFS are doing on the strat isn’t stopping them producing an eye catching block in the trop mind!

Yes, these are two seperate models.

[bluearmy]

4 minutes ago, Uncertainty said:

Are you saying the eps are showing a mean reversal Nick? That would be quite something. And am I right in saying that the the 46 is now fundamentally a separate model and won’t necessarily follow on from the eps? 
 

Whatever the GEFS are doing on the strat isn’t stopping them producing an eye catching block in the trop mind!

The 3040 dam contour which is the outside of the strat low straddles the pole - can’t see for sure but v close if is isn’t 

given that the gefs are not as displaced, you’d have to say that the eps are probably progressive. However, the date ties in with the 46 clustering 

[Frostbite80]

Most members of the CFS now showing a reversal by mid Jan and some significantly so - even record breakingly so

[bluearmy]

Looking at the evolution of the gfs and ec strat warming over the next few days, they begin to depart from one another by day 3. That’s very early and something isn’t right here. however, this variation in timing has been showing for a week now. at 10hpa, we would expect to see solid agreement at short lead times. 

the-point here is that gfs being later on the warming allows the spv to get further east before it begins to be pushed back across the NH by the warming. Hence it makes its rotation closer to the pole and ends up near n Greenland by day 16.  Ec warms faster and the spv doesn’t get much past nov zem before it’s pushed back and rotates. Hence that journey ends up closer to the Barents sea and the vortex stays displaced. This makes a tech ssw more likely to happen faster than the gfs which isn’t displaced at the end of week 2 and requires another cycle of warming to push it back to Asian side.  You could make a case that the gfs solution has a greater chance of a split mid jan because a weaker vortex is likely to be stretched in week 3 and then have wave pressure applied to it. 
 

the gfs 06z doubles down and is even slower on the warming than the 00z. Wonder how that will affect the journey of the spv when it comes under pressure 

 

7 minutes ago, Frostbite80 said:

Most members of the CFS now showing a reversal by mid Jan and some significantly so - even record breakingly so

The latest cfs monthly is as wintry as I’ve seen it for JFM 

Edited December 22, 2023 by bluearmy

[Frostbite80]

2 minutes ago, bluearmy said:

Looking at the evolution of the gfs and ec strat warming over the next few days, they begin to depart from one another by day 3. That’s very early and something isn’t right here. however, this variation in timing has been showing for a week now. at 10hpa, we would expect to see solid agreement at short lead times. 

the-point here is that gfs being later on the warming allows the spv to get further east before it begins to be pushed back across the NH by the warming. Hence it makes its rotation closer to the pole and ends up near n Greenland by day 16.  Ec warms faster and the spv doesn’t get much past nov zem before it’s pushed back and rotates. Hence that journey ends up closer to the Barents sea and the vortex stays displaced. This makes a tech ssw more likely to happen faster than the gfs which isn’t displaced at the end of week 2 and requires another cycle of warming to push it back to Asian side.  You could make a case that the gfs solution has a greater chance of a split mid jan because a weaker vortex is likely to be stretched in week 3 and then have wave pressure applied to it. 

The latest cfs monthly is as wintry as I’ve seen it for JFM 

I have no doubt a SSW will occur the only niggling thing in my head is that it wont help us favourably. I feel the rest of the winter will be determined by the SSW. I feel it could be one of the best cold spells for the heart of winter for some time or it could end up mild throughout, however this time I am punting for the colder option.

[ICE COLD]

1 minute ago, bluearmy said:

Looking at the evolution of the gfs and ec strat warming over the next few days, they begin to depart from one another by day 3. That’s very early and something isn’t right here. however, this variation in timing has been showing for a week now. at 10hpa, we would expect to see solid agreement at short lead times. 

the-point here is that gfs being later on the warming allows the spv to get further east before it begins to be pushed back across the NH by the warming. Hence it makes its rotation closer to the pole and ends up near n Greenland by day 16.  Ec warms faster and the spv doesn’t get much past nov zem before it’s pushed back and rotates. Hence that journey ends up closer to the Barents sea and the vortex stays displaced. This makes a tech ssw more likely to happen faster than the gfs which isn’t displaced at the end of week 2 and requires another cycle of warming to push it back to Asian side.  You could make a case that the gfs solution has a greater chance of a split mid jan because a weaker vortex is likely to be stretched in week 3 and then have wave pressure applied to it. 

Surely you would have thought the ECM has got this over GFS tho wouldn’t you ? Especially at day 3 . That’s seems really poor at day 3 one of these has got it wrong especially high up when it’s meant to be more reliable forecasting higher up . I suppose we shall soon see who has it right ……. 

[bluearmy]

32 minutes ago, ICE COLD said:

Surely you would have thought the ECM has got this over GFS tho wouldn’t you ? Especially at day 3 . That’s seems really poor at day 3 one of these has got it wrong especially high up when it’s meant to be more reliable forecasting higher up . I suppose we shall soon see who has it right ……. 

You’d think so wouldn’t you 

the 06z gfs is even slower with the warming but this has an unexpected consequence of rotating the vortex back towards svaalbard/barents so that by day 16 it’s close the the gefs and not far from the eps  ( this illustrates that you simply can’t assume that a+b=c ) 

[Andy8472]

NASA model has sightly different positioning with more warming into the pole along with the GFS mean at 240 

[Andy8472]

From yesterdays ECM

[Andy8472]

Not a bad stretch plus EPS from this morning

[bluearmy]

1 hour ago, Andy8472 said:

Not a bad stretch plus EPS from this morning

About 21 members again 

and that mean so close to zero as expected 

the 12z gfs is back to where the 00z run was with the spv n Greenland at the end of the run and fairly stretched 

looking at the 10hpa wind gives a better feel of where the vortex actually is sitting (rather than the temps ) 

Edited December 22, 2023 by bluearmy

[bluearmy]

Lost the momentum on the reversal on the 46

[sebastiaan1973]

Almost the same output as yesterday. Look at the lowest average, around 5 m/s