Stratosphere and Polar Vortex Watch 2020

[Catacol]

19 minutes ago, mountain shadow said:

I thought QBO effects were slow burners and anythings happening now unlikely to impact on this Winter?

The QBO is certainly one of the list of drivers that impacts our patterns (it impacts on the amount of wave flux that makes it poleward from equatorial regions) - but never have we seen a profile that looks anything like the 2020 profile. Genuinely unique and therefore a complete wild card in terms of impacts. 

[ghoneym]

3 hours ago, Catacol said:

Jinkies - take a look at the QBO profile put out here by Amy Butler just now on Twitter. Anyone care to take a punt on what this profile will do to our winter synpotics??????

I have been pondering the QBO pattern for a few days now and as you say there has been lots of discussion on twitter with regards this years pattern.  As a punt could I suggest that Covid 19 has had a bearing on the pattern? Bear with me I'm not a conspiracy theorist....what I remember from the peak pandemic were news reports of much cleaner air globally due to lack of moving traffic, industry shut down, flights grounded etc.

      

Around 40% of Nitrous oxide emissions comes from human activity, (listed above as transport/industry) the N2O is a greenhouse gas that breaks down the ozone layer long term, N20 also absorbs solar radiation however and traps heat in the upper atmosphere, so as a short term effect are wee seeing some kind of feedback mechanism from this as the images above show for a good quarter of the year we had a huge reduction in N20 in the atmosphere, allowing more of the solar radiation to penetrate to the surface, hence the extended wildfires and elevated SST's we are experiencing?

Having said all that I'm at a loss as N20 levels in the stratosphere when exposed to sunlight and oxygen transform the gas into Nitrogen Oxides which also damage the Ozone.  So again due to the lack of N20 we haven't been damaging the Ozone as much this year.  I thought I would have seen this improvement on the NASA total column ozone charts as the year has progressed but currently to no avail.  

It is possible that the short term effect of lower N20 level have allowed through more solar radiation than the effect of Ozone breakdown which takes considerably longer?  

My missing link is how this is linked to the QBO pattern, but I have a hunch lol and the theory I'm still working on......

[swebby]

2 hours ago, Catacol said:

The QBO is certainly one of the list of drivers that impacts our patterns (it impacts on the amount of wave flux that makes it poleward from equatorial regions) - but never have we seen a profile that looks anything like the 2020 profile. Genuinely unique and therefore a complete wild card in terms of impacts. 

Honest Qu as i have only a very basic understanding of the QBO.

Is it genuinely totally unlike anything we have seen before?  It seems to me to look a lot like 1989-1992, other than <20mb region being rather non descript, or is that the key region?

[chionomaniac]

Wave two seems to wane at day 10 on latest runs. Could do with reinforcing to help with Greenland heights. Looks like the waning is occurring just as the MJO is shifting east though so this may help

[Catacol]

3 hours ago, swebby said:

Honest Qu as i have only a very basic understanding of the QBO.

Is it genuinely totally unlike anything we have seen before?  It seems to me to look a lot like 1989-1992, other than <20mb region being rather non descript, or is that the key region?

I see what you mean re 89-92 but I think the mixed setup of 2020 really is unique. What the key region is is an excellent question. The point is that usually there is a reasonably uniform descending pattern of westerlies or easterlies. There is no way the current pattern is uniform. I can’t really offer an answer to your question because my knowledge of the QBO as a detailed factor is not sufficient.,,,but then again most experts online seem to be shrugging their shoulders because we have no historic parallel to base a judgement on. I’m of the view that the QBO is not one of the biggest drivers....but nonetheless it does offer a sense of intrigue to the season as we kick off....

[Catacol]

1 hour ago, chionomaniac said:

Wave two seems to wane at day 10 on latest runs. Could do with reinforcing to help with Greenland heights. Looks like the waning is occurring just as the MJO is shifting east though so this may help

ECM wave forecast also slightly less today. Wave 1 remaining around the same. As I mused earlier - falling relative GLAAM now and examination of the frictional graphs might mean a slightly later kick off. I’d kind of nailed my thoughts a while back to approx 20 Dec for an uptick in the blocking signal across the final third of the month - it might be a day or three later now perhaps. Over many years I’ve found predicted timings often run a bit late. Like my damned solicitors as I try and move house.....

[Daniel*]

2 hours ago, chionomaniac said:

Wave two seems to wane at day 10 on latest runs. Could do with reinforcing to help with Greenland heights. Looks like the waning is occurring just as the MJO is shifting east though so this may help

ECM 12z looks promising? It’s a large change from current concentric shape.

 

[chionomaniac]

4 minutes ago, Daniel* said:

ECM 12z looks promising? It’s a large change from current concentric shape.

 

Yep and that is at 10hPa . But will still need another kick

[Mike Poole]

With the appearance of the Arctic high it is perhaps no surprise that the AO is going negative, but I’m struck by the NAM plot yet again (forecast from GFS 0z):

-2 consistently now in the trop and +something in the strat.  So a big disconnect there between trop and strat continues for the foreseeable.  Now the zonal winds:

What struck me about this is how close the GFS op and ensemble mean is.  Now they are both singing from the FV3 hymn book.  Last year, the GEFS tried to suggest a warming event and the FV3 op wanted nothing to do with it.  The stragglers down to really low zonal winds tend to be the GEM (CMC) ensembles.  All of which leads me to the conclusion it will take more than this to bring this vortex down.  Early days though...

Edited December 9, 2020 by Mike Poole

[Catacol]

This zonal wind speed forecast is starting to get quite significant. There is a clear signal for reverse flow on average, and as far south as 60N for that matter, and up as high as 100hpa over the pole. A good sign overall.

Edited December 10, 2020 by Catacol

[Griff]

Always surprised no one has posted this sooner, in any case I'm staying away from the model thread, far too emotional... 

Seems to continue the theme with a lot of scatter but signs of a weaker than normal means... 

[sebastiaan1973]

Just now, Griff said:

Always surprised no one has posted this sooner, in any case I'm staying away from the model thread, far too emotional... 

Seems to continue the theme with a lot of scatter but signs of a weaker than normal means... 

Well, it just a quarter of hour available

MJO phase 6,7 for a part of the EC46 output.

[Griff]

Just now, sebastiaan1973 said:

Well, it just a quarter of hour available

MJO phase 6,7 for a part of the EC46 output.

It could be a lot worse 

[bluearmy]

34 minutes ago, Griff said:

It could be a lot worse 

 Not much sign of any amplitude though 

 noted the uptick in zonal winds high up just before Xmas before dropping back below average 

[bluearmy]

3 hours ago, Snow lover 2020 said:

Apparently the GFS is showing a stronger vortex. No SSW!! This is winter of doom again 

Where ?

[SqueakheartLW]

Think GFS is looking in the mirror at last years zonal wind speeds

When looking at its 2 week forecast the red line is the average and it is an exact mirror opposite to what happened last year

Now if that were to continue then the path should follow the blue line I have drawn. This would mean 3 reversals in total between now and the spring with a modest reversal in early to mid January then a much larger reversal in February before a final one in late March which kills off the vortex completely.

[bluearmy]

33 minutes ago, SqueakheartLW said:

Think GFS is looking in the mirror at last years zonal wind speeds

When looking at its 2 week forecast the red line is the average and it is an exact mirror opposite to what happened last year

Now if that were to continue then the path should follow the blue line I have drawn. This would mean 3 reversals in total between now and the spring with a modest reversal in early to mid January then a much larger reversal in February before a final one in late March which kills off the vortex completely.

euromillions tonight is £175m - could you DM me the winning numbers please

[Daniel*]

Not a bad way to end year....

[chionomaniac]

It’s certainly worth watching the upper strat for a strong wave 1 warming. Many GFs runs have suggested this at the end of the runs. I’m not a great fan of wave 1 warming’s for us in the uk but anything that can weaken the vortex is welcome. And these warmings would be strong enough to significantly weaken the vortex or even cause a SSW were they to reel in.  Wouldn’t be surprised to see a SSW first 10 days of January.

[stodge]

50 minutes ago, chionomaniac said:

It’s certainly worth watching the upper strat for a strong wave 1 warming. Many GFs runs have suggested this at the end of the runs. I’m not a great fan of wave 1 warming’s for us in the uk but anything that can weaken the vortex is welcome. And these warmings would be strong enough to significantly weaken the vortex or even cause a SSW were they to reel in.  Wouldn’t be surprised to see a SSW first 10 days of January.

I'm no fan of Wave 1 warmings from the Siberian side either. All they do is send the PV back to Canada where it can re-strengthen.  Tonight's GFS 12Z OP suggests an initial Wave 1 hit followed by a second much stronger attack between Christmas and New Year. It's not enough to split the PV of course but it does weaken it and reduce the zonal wind speeds further which helps in terms of allowing amplification and offering the chance for heights to build over Greenland or Scandinavia.

[chionomaniac]

9 minutes ago, stodge said:

I'm no fan of Wave 1 warmings from the Siberian side either. All they do is send the PV back to Canada where it can re-strengthen.  Tonight's GFS 12Z OP suggests an initial Wave 1 hit followed by a second much stronger attack between Christmas and New Year. It's not enough to split the PV of course but it does weaken it and reduce the zonal wind speeds further which helps in terms of allowing amplification and offering the chance for heights to build over Greenland or Scandinavia.

Wave 1 attacks are never the preference, but if we can get enough of a PV weakening, then hopefully that will open the door for upper cut trop based wave 2 assaults. 10hPa u wind hasn’t really got going this season. In other years we see forecast above 60m/s at this point. Currently 40m/s is the max forecast. 

 

[Catacol]

1 hour ago, chionomaniac said:

Wave 1 attacks are never the preference, but if we can get enough of a PV weakening, then hopefully that will open the door for upper cut trop based wave 2 assaults. 10hPa u wind hasn’t really got going this season. In other years we see forecast above 60m/s at this point. Currently 40m/s is the max forecast. 

 

Yes. I like the image of a trop uppercut! And that the day after AJ....

From this longer term angle I’d prefer to see any blocking ridge in the new year period once again set up shop over Scandy and Russia even if this brings some more mild/wet solutions. The MetO long range is suggesting mild/wet for early January - and provided this isn’t from a full zonal onslaught running right through Scandy then I’ll be happy to see more disrupting systems bumping into the ScEuro ridge as wave 2 gets cracking - and this time at greater amplitude perhaps. This winter was never about the first half of January to me. Some short term chances in December....but the game has always been about full blown split SSW and then downwelling impacts at the end of January into February. I’ve gone for Jan 23....

[ghoneym]

3 hours ago, chionomaniac said:

Wave 1 attacks are never the preference, but if we can get enough of a PV weakening, then hopefully that will open the door for upper cut trop based wave 2 assaults. 10hPa u wind hasn’t really got going this season. In other years we see forecast above 60m/s at this point. Currently 40m/s is the max forecast. 

 

Sorry to be a pain in butt...but it looks to me that the mean wind speed for this time of year is 40 m/s and to be up at 60m/s we would be looking at breaking records? I'm not trying to be pedantic or anything but just want to try and understand what I'm looking at from the various different charts available.

Wave 1 is on top for now that is for sure.

 

 

[Daniel*]

 

[DavidS]

00z keeps the theme going, with a significant warming showing.