Polar Vortex / Stratosphere Watch 2022 / 2023

[Catacol]

I'm struck at 10 days how far off centre the 10hpa vortex is becoming, and through the layers it is lacking coherence of shape. A 90 degree twisted stretch profile. The extent to which a setup like this puts it close to being wobbled and squashed to the point of no return I do not have the skill to see - but for a mid December vortex it looks rather unhappy to me.

[chionomaniac]

1 minute ago, Catacol said:

I'm struck at 10 days how far off centre the 10hpa vortex is becoming, and through the layers it is lacking coherence of shape. A 90 degree twisted stretch profile. The extent to which a setup like this puts it close to being wobbled and squashed to the point of no return I do not have the skill to see - but for a mid December vortex it looks rather unhappy to me.

It’s the baroclinic tilt throughout the Strat that will be all important in bringing the Strat down. Lovely view there

[bluearmy]

The 12z gfs brings the 10 hpa zonal flow down to 10 m/s late on in week 2.  That’s v low for December. 

There is a reversal at 1 hpa above 80 N 

[chionomaniac]

3 minutes ago, bluearmy said:

The 12z gfs brings the 10 hpa zonal flow down to 10 m/s late on in week 2.  That’s v low for December. 

There is a reversal at 1 hpa above 80 N 

That’s good and close to what I had worked out just looking at the models. Tilt excellent too. Just a few more pumps of hot air and the balloon will fly and the Strat will be brought down. What’s good is that we are seeing a consistent but strengthening signal here, and I believe similar with Eps. Perhaps we will just get a SSW before Jan - either way it will be a close run thing. 

[SqueakheartLW]

It's still showing up and not only weaker than average in the stat but also look at the increasing signal for a weak jet in the trop which only means one thing, blocking.

The main thing is where the blocking is

Strange that in this WQBO winter as well as the previous one in 2020/21 we have signals for a SSW yet in the EQBO winter of 2021/22 we came no where near getting even a minor warming

What happened to the EQBO enhancing SSW prospects whilst WQBO reducing them?

[Don]

3 hours ago, chionomaniac said:

Perhaps we will just get a SSW before Jan - either way it will be a close run thing. 

As long as a SSW doesn't lead us into a milder pattern further down the line?!

[bluearmy]

13 hours ago, Don said:

As long as a SSW doesn't lead us into a milder pattern further down the line?!

Blocking patterns don’t tend to last for more than three weeks so I’d say an ssw would be welcome and the earlier in Jan the better.  However, ec46 and glosea aren’t seeing anything at this time. most extended modelling are seeing a westerly return for Jan so if we’ve had a two or three weeks of decent cold in December then maybe a roll of the dice for Jan and feb post ssw  would be reasonable !  

Edited December 8, 2022 by bluearmy

[Don]

48 minutes ago, bluearmy said:

Blocking patterns don’t tend to last for more than three weeks so I’d say an ssw would be welcome and the earlier in Jan the better.  However, ec46 and glosea aren’t seeing anything at this time. most extended modelling are seeing a westerly return for Jan so if we’ve had a two or three weeks of decent cold in December then maybe a roll of the dice for Jan and feb post ssw  would be reasonable !  

All the more reason to make the most of this current cold spell and hope it delivers some widespread snow before it ends!

[phil nw.]

The lower Strat still showing weak zonal winds even though at the top normal speeds abound.

Just shows the disconnect that continues towards Christmas.

 

The upper vortex continues to get pushed around from wave 1 warmings.

All points to another couple of weeks of troposphere blocking and a southerly tracking jet.

[SqueakheartLW]

24 minutes ago, phil nw. said:

The lower Strat still showing weak zonal winds even though at the top normal speeds abound.

Just shows the disconnect that continues towards Christmas.

 

The upper vortex continues to get pushed around from wave 1 warmings.

All points to another couple of weeks of troposphere blocking and a southerly tracking jet.

Definitely similar to 1995 and 2010 in that regard. Both of those had robust vortex at 10hpa with a big disconnect below in the trop.

What's different to those years is the repeated wave 1 warmings which could be what makes the difference and ensures a chance of longer cold rather than a front loaded winter that goes away.

1995/96 is a better match for a more all rounded cold winter over 2010/11

Seems it's the MJO and the EP La Nina driving the pattern this year instead of that pesky vortex.

[bluearmy]

A sudden change in the ec 46 takes the zonal wind right up above 50m/s just after Xmas before it drops back towards average through the first half of Jan 

certainly a marked shift from this model - I have noticed the gfs fi beginning to ramp up the 10 hpa flow later week 2.  Some runs are  bringing the strengthening flow down to the trop but at a latitude around 50N 

[Don]

3 hours ago, bluearmy said:

A sudden change in the ec 46 takes the zonal wind right up above 50m/s just after Xmas before it drops back towards average through the first half of Jan 

certainly a marked shift from this model - I have noticed the gfs fi beginning to ramp up the 10 hpa flow later week 2.  Some runs are  bringing the strengthening flow down to the trop but at a latitude around 50N 

I hope those who have had snow during this cold spell have made the most of it!!  Amazing how things can fall apart so rapidly!!

[bluearmy]

@chionomaniac - is the sudden ec46 rush to 50 m/s an anomaly?? 
 

It is 90% + supported 

 

[chionomaniac]

1 minute ago, bluearmy said:

@chionomaniac - is the sudden ec46 rush to 50 m/s an anomaly?? 
 

It is 90% + supported 

 

Not really. I guess I had expected the western Pacific activity to get a move on a bit earlier to keep the pressure on the upper Strat. Pressure has been felt most at 1hPa with strong wave 1 activity, but this hasn’t translated down to 10hPa. 
 

it’s a bit like the balloon analogy, pressure has been placed on the balloon - but critically it has not popped, nor has any air escaped. So remove that pressure, and the balloon regains it’s shape quickly. That’s effectively what’s happened at 10hPA ( air escaped at 1hPa) so now we have to wait until the NH profile is conducive to further wave activity reflecting into the Strat. And by God, some of the modelling of the NH profile will surely be conducive to that!

[Frostbite1980]

This isn't what you want to see if we are looking for a SSW?

[Don]

19 minutes ago, Frostbite1980 said:

This isn't what you want to see if we are looking for a SSW?

No it's not!!  A pear shaped winter?!!  Going by that we can expect another PV of doom moving forward!

Edited December 13, 2022 by Don

[Frostbite1980]

7 minutes ago, Don said:

No it's not!!  A pear shaped winter?!!  Going by that we can expect another PV of doom moving forward!

I Know the vortex isn't coupled but after the beating up of the upper vortex I was surprised to see this.......some of the CFS runs going for a record strength at 10 hpa

[Don]

2 minutes ago, Frostbite1980 said:

I Know the vortex isn't coupled but after the beating up of the upper vortex I was surprised to see this.......some of the CFS runs going for a record strength at 10 hpa

We will likely know all about it when the vortex does couple according to the CFS and looks like it's happening now? 

[Frostbite1980]

5 minutes ago, Don said:

We will likely know all about it when the vortex does couple according to the CFS and looks like it's happening now? 

Maybe Chio or Blue will be able to help answer this one 😝

[Don]

21 minutes ago, Frostbite1980 said:

Maybe Chio or Blue will be able to help answer this one 😝

Absolutely! 👍

[chionomaniac]

I would say personally that we still have a bit of time on our hands - perhaps until the end of the year before upper zonal winds will start to propagate to the trop. Until this point the coupling will still be broken.

At every level except 2hPA the strat u wind is around average and this decreases the lower you get

2hPA

10Hpa

70Hpa

!00Hpa

 

[Frostbite1980]

32 minutes ago, chionomaniac said:

I would say personally that we still have a bit of time on our hands - perhaps until the end of the year before upper zonal winds will start to propagate to the trop. Until this point the coupling will still be broken.

At every level except 2hPA the strat u wind is around average and this decreases the lower you get

2hPA

10Hpa

70Hpa

!00Hpa

 

Thanks for that Chio, does this mean that the chances of a SSW is decreasing if the trop couples in the new year?

[chionomaniac]

1 hour ago, Frostbite1980 said:

Thanks for that Chio, does this mean that the chances of a SSW is decreasing if the trop couples in the new year?

No SSW is to do with trop wave activity 

[Don]

5 hours ago, chionomaniac said:

I would say personally that we still have a bit of time on our hands - perhaps until the end of the year before upper zonal winds will start to propagate to the trop. Until this point the coupling will still be broken.

Thanks for the thoughts.  Hmm, perhaps my earlier comments were a little hasty?! 🙄

[SqueakheartLW]

The disconnect shows up nicely here with those above average red anomalies from 40hpa upwards and those below average blue anomalies below 40hpa.

I'd say we are still very much game on for trop blocking and a year similar to 1995/96.