Stratosphere and Polar Vortex Watch 2020

[JeffC]

7 minutes ago, frederiksen90 said:

Men en svækkelse i forhold til mandagens ensemble-kørsel. Ret stor ændring: https://stream.ecmwf.int/data/gorax-green-001/data/scratch/20201112-0600/d7/ps2png-gorax-green-001-6fe5cac1a363ec1525f54343b6cc9fd8-7oWzWZ.png Fra noget, der udviklede sig til en stabil stærk PV, er det nu en større ændring. Måske en tendens mod en stor svækkelse, som bliver endnu tydeligere i næste kørsel på mandag?

Couldn't have said it better myself!

[RJBingham]

12 hours ago, frederiksen90 said:

But a weakening compared to Monday's ensemble run. Quite a big change: https: // stream. ecmwf .int / data / gorax-green-001 / data / scratch / 20201112-0600 / d7 / ps2png-gorax-green-001-6fe5cac1a363ec1525f54343b6cc9fd8-7oWzWZ.png From something that evolved into a stable strong PV , it is now a major change. Perhaps a trend towards a major weakening, which will become even clearer in the next run on Monday?

Google translation 

Edited November 13, 2020 by RJBingham

[SqueakheartLW]

Starting to look like the troposphere and stratosphere are heading in different directions in the next couple of weeks at least

Polar Vortex status and predictions

Both GFS and CFS appear to be ramping up the zonal winds in the next couple of weeks although the CFS and CFS biased corrected lines are showing a lot of scatter after this right from reversals up to polar vortex of doom status

However the tropospheric forecast looks much different

Even though you can see all those reds in the anomaly chart high up in the stratosphere the tropospheric level shows some blues which are weaker than average zonal winds. Maybe another 2010 could be on the cards here with a raging vortex high up and a very slack and blocked pattern lower down, one can only hope for a December 2010 repeat

[Kirkcaldy Weather]

 

[Duane S.]

The connection to the eventual weather on our side of the hemisphere maybe tenuous but far from completely unconnected, so I found this very interesting. I was thinking about last SH spring’s highly anomalous temperatures in their high latitudes and look how this year we have opposite extremes in the upper troposphere to mid stratosphere.

Both way outside the climatic norms.
 

 

 

 

[snowking]

 

45 minutes ago, s4lancia said:

The connection to the eventual weather on our side of the hemisphere maybe tenuous but far from completely unconnected, so I found this very interesting. I was thinking about last SH spring’s highly anomalous temperatures in their high latitudes and look how this year we have opposite extremes in the upper troposphere to mid stratosphere.

Both way outside the climatic norms.
 

 

 

 

In terms of a connection, this would certainly suggest to me that the there is less ozone transport to the SH this year, although whether this is consequential of greater NH poleward ozone transfer, or a generally weaker BDC overall (which would be expected in a La Niña, wQBO year) I couldn’t say.

Hope it’s the former!

Edited November 15, 2020 by snowking

[bluearmy]

12 hours ago, Kirkcaldy Weather said:

 

Will take little from that other than the ec seasonal isn’t predicting a very strong spv for the winter .....

 

[SqueakheartLW]

CFS is going for it yet again

Like a week or so ago another record breaking SSW event leading to "zonal" easterlies. 3 runs go into a reversal at some stage but one of them is a polar vortex of doom run

Even the bias corrected chart still has 2 reversals but also has a record strong vortex showing up too.

Hope those top ones don't come off. A zonal wind getting on for 100m/s would be unreal

[bluearmy]

1 hour ago, SqueakheartLW said:

Hope those top ones don't come off. A zonal wind getting on for 100m/s would be unreal

I’d take it ...... suspect it would lead to a ‘big burst of the balloon’ as it’s surely unsustainable (no scientific basis for this view!)

Edited November 15, 2020 by bluearmy

[feb1991blizzard]

1 hour ago, bluearmy said:

I’d take it ...... suspect it would lead to a ‘big burst of the balloon’ as it’s surely unsustainable (no scientific basis for this view!)

I always used to think that bas baloney but now i think it has merit, if it imprints on the trop, as long as its early, the trop vortex will just carry on growing in size, but at some point the temperature gradient that fuels the jet will be so high as it encounters more and more tropical air such that somewhere around the globe a wave will be distinct enough to advect tropical air North and bang, the bigger they are, the harder they fall.

[Catacol]

Polar vortex vertical temperature gradient has certainly got off to an early and vigorous start - 6 weeks ahead of itself.

However an SSW I reckon still to be a distinct possibility. Already money in the bank with regards to the tropospheric ridge/trough pattern and the current persistence of the ScEuro high opens up disruptive possibilities in the second half of December and on into January. And the faster it spins, the bigger it crashes....should the forcing emerge to create that crash. The balance of probability sits in favour of a zonal winter overall at the moment....but I just watched Argentina beat the ABs. Stuff happens - sometimes big stuff.........

Edited November 15, 2020 by Catacol

[mb018538]

8 hours ago, Catacol said:

Polar vortex vertical temperature gradient has certainly got off to an early and vigorous start - 6 weeks ahead of itself.

However an SSW I reckon still to be a distinct possibility. Already money in the bank with regards to the tropospheric ridge/trough pattern and the current persistence of the ScEuro high opens up disruptive possibilities in the second half of December and on into January. And the faster it spins, the bigger it crashes....should the forcing emerge to create that crash. The balance of probability sits in favour of a zonal winter overall at the moment....but I just watched Argentina beat the ABs. Stuff happens - sometimes big stuff.........

No really a big surprise given how strong the PV has been since the middle of October. Heading up to the 2 SD above normal bracket again. 

As you say though, the bigger they are, the harder they fall!

[SqueakheartLW]

Still looks like the zonal winds are going off the scale in the next 2 weeks

We reach the pink colours on the left chart which is the highest the scale goes to on here - POLAR VORTEX OF DOOM ALERT !!!

However it appears this vortex is going to fail to couple to the tropospheric vortex as zonal winds lower down are going to remain average at most and more often below average

+35m/s above average at 1hpa by the end of the run in contrast to -5m/s weaker than average at 300hpa which is roughly jet stream height

Yet again CFS is throwing in another massive teaser record breaking zonal wind reversal, this time mid to late January 2021

Either the CFS is on to something here or it is just behaving like the CFS does and throws up these wild scenarios every couple of days or so. However the bias corrected runs are still showing polar vortex of doom options at the top end

[bluearmy]

1 hour ago, SqueakheartLW said:

Still looks like the zonal winds are going off the scale in the next 2 weeks

We reach the pink colours on the left chart which is the highest the scale goes to on here - POLAR VORTEX OF DOOM ALERT !!!

However it appears this vortex is going to fail to couple to the tropospheric vortex as zonal winds lower down are going to remain average at most and more often below average

+35m/s above average at 1hpa by the end of the run in contrast to -5m/s weaker than average at 300hpa which is roughly jet stream height

Yet again CFS is throwing in another massive teaser record breaking zonal wind reversal, this time mid to late January 2021

Either the CFS is on to something here or it is just behaving like the CFS does and throws up these wild scenarios every couple of days or so. However the bias corrected runs are still showing polar vortex of doom options at the top end

it could take a little while for that upper flow to work its way down but the chance of a strong spv downwelling into the trop is way stronger than a reversal

[mb018538]

34 minutes ago, bluearmy said:

it could take a little while for that upper flow to work its way down but the chance of a strong spv downwelling into the trop is way stronger than a reversal

If the strat and trop start holding hands at that sort of strength that it could be a pretty bumpy ride ahead, especially given the forecasts for the second half of winter. 

We're ok for now - but could end up in the 'all eggs in the SSW basket' territory. It'll be an interesting few weeks ahead.

[Don]

3 hours ago, SqueakheartLW said:

 

However the bias corrected runs are still showing polar vortex of doom options at the top end

Indeed, a couple of those bias corrected runs look somewhat alarming for January and February!  They are outliers but who knows these days?!

[Cheshire Freeze]

You just get the feeling that if we do get a SSW in Jan, it could be spectacular this year...given how strong the SPV is forecast to become.

[Catacol]

1 hour ago, CreweCold said:

You just get the feeling that if we do get a SSW in Jan, it could be spectacular this year...given how strong the SPV is forecast to become.

Yes. If it can be nudged off it’s axis and then squeezed via wave 2 then my very basic understanding of physics suggests it will be vulnerable given those predicted high wind speeds. Seeing as a category 5 hurricane is about to be recorded (if not already) in the second half of November then all bets on weather extremes continue to be off. Everywhere we look we see data pushing the boundaries of normal. Spectacular winter events will happen somewhere this season - I’m sure of it. Cross fingers though it isn’t spectacular U.K. warmth on a tropical long draw SW feed. A nice long draw easterly from the heart of Siberia striking in the middle of January would be just the ticket...

[Don]

2 hours ago, CreweCold said:

You just get the feeling that if we do get a SSW in Jan, it could be spectacular this year...given how strong the SPV is forecast to become.

Yes it could be but if we don’t get a SSW.....

[Robbie Garrett]

2 hours ago, Don said:

Yes it could be but if we don’t get a SSW.....

Raging Zonality right?

 

23 hours ago, Catacol said:

Polar vortex vertical temperature gradient has certainly got off to an early and vigorous start - 6 weeks ahead of itself.

However an SSW I reckon still to be a distinct possibility. Already money in the bank with regards to the tropospheric ridge/trough pattern and the current persistence of the ScEuro high opens up disruptive possibilities in the second half of December and on into January. And the faster it spins, the bigger it crashes....should the forcing emerge to create that crash. The balance of probability sits in favour of a zonal winter overall at the moment....but I just watched Argentina beat the ABs. Stuff happens - sometimes big stuff.........

Does low sea ice extent force this vigorous start? Reminds me of Day after Tomorrow and how mother nature fights back...

[lorenzo]

Only way is up !!!

 

[Catacol]

59 minutes ago, lorenzo said:

Only way is up !!!

 

Ha I blo*dy hope so. If we get any more signals pointing to Uber Vortex II I’m going to start head butting the wall.......

[Cheshire Freeze]

2 hours ago, Catacol said:

Ha I blo*dy hope so. If we get any more signals pointing to Uber Vortex II I’m going to start head butting the wall.......

To be fair, if we did get a record strength vortex, we could get lucky and see a nudge to our side of the hemisphere. Would surely bring some very cold zonal...

[SqueakheartLW]

Institute of meteorology charts for zonal winds clearly show up the stratospheric and tropospheric vortexes failing to couple to each other in the next 10 days

Latest

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 9

Day 10

Even though the zonal winds go through the roof at 1hpa you will notice how little of the increase makes it below 50hpa and in fact the tropical jet stream stays consistent at around 30 m/s. The polar jet on these charts is so weak and displaced northwards on average and in fact around 60N near the surface we have average easterlies at times too. A significant sign of northern blocking setting up during this period but crucially for us, where in the N hemisphere is it going to set up

Also notice how the EQBO at 10hpa is beginning to link up to the forming anti vortex in the S Hemisphere. Wonder if this will give it a nice boost and help to push the WQBO lower down. Probably not much help for us this winter now but it could at least weaken the WQBO on average for this winter and set us up nicely with an established EQBO for next year, assuming we don't get another disruption event.

Talking more of the QBO it is now clear how much the new EQBO is building up at the 10 to 15hpa level but so far it has barely got any lower down and NASA Singapore site keeps switching between Westerly Phase and East, Descending Phase on this plot

It is clearer to see on this chart what progress has been made by the new EQBO. It has strengthen but so far has hardly descended but it appears it has started to get lower down to a small degree at least, too late now for this winter but maybe going to be of great help for next year

The MERRA chart shows that the EQBO has on average descended down and may be a more accurate chart since it is an average of the whole equatorial stratosphere rather than just the measurement above Singapore which is very likely to vary much more compared with the average situation. The strengthening of the EQBO shows up clearly on here and with the higher WQBO speeds descending on average we may see a 10+ figure for November QBO at 30hpa but I feel the December number is going to be lower based on what this chart is showing

[Griff]

55 minutes ago, SqueakheartLW said:

Institute of meteorology charts for zonal winds clearly show up the stratospheric and tropospheric vortexes failing to couple to each other in the next 10 days

Latest

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 9

Day 10

Even though the zonal winds go through the roof at 1hpa you will notice how little of the increase makes it below 50hpa and in fact the tropical jet stream stays consistent at around 30 m/s. The polar jet on these charts is so weak and displaced northwards on average and in fact around 60N near the surface we have average easterlies at times too. A significant sign of northern blocking setting up during this period but crucially for us, where in the N hemisphere is it going to set up

Also notice how the EQBO at 10hpa is beginning to link up to the forming anti vortex in the S Hemisphere. Wonder if this will give it a nice boost and help to push the WQBO lower down. Probably not much help for us this winter now but it could at least weaken the WQBO on average for this winter and set us up nicely with an established EQBO for next year, assuming we don't get another disruption event.

Talking more of the QBO it is now clear how much the new EQBO is building up at the 10 to 15hpa level but so far it has barely got any lower down and NASA Singapore site keeps switching between Westerly Phase and East, Descending Phase on this plot

It is clearer to see on this chart what progress has been made by the new EQBO. It has strengthen but so far has hardly descended but it appears it has started to get lower down to a small degree at least, too late now for this winter but maybe going to be of great help for next year

The MERRA chart shows that the EQBO has on average descended down and may be a more accurate chart since it is an average of the whole equatorial stratosphere rather than just the measurement above Singapore which is very likely to vary much more compared with the average situation. The strengthening of the EQBO shows up clearly on here and with the higher WQBO speeds descending on average we may see a 10+ figure for November QBO at 30hpa but I feel the December number is going to be lower based on what this chart is showing

Interesting chatter on twitter (see what I did there) discussing similar disconnect. See tweet thread!