Stratosphere Temperature Watch 2012/2013

[Recretos]

I was a bit bored, so I plotted some graphics (Hovmoller diagram) about this SSW, from the NCEP/DOE Reanalysis (R-2), which has 4x daily rotating archive. Nothing special. I think it should be interesting for some. These are custom made, so for now only me and Netweather have them, and published. Of course in this "form". There might be graphics out there in a similar style of the same level and parameter.

All these graphics represent zonal means. Data courtesy of NCEP.

And I plotted the 10mb 60N zonal wind, for a better estimate of the actual SSW timing.

And since I was even more bored, I plotted Hovmoller diagram of the 18z GFS.

And 2 graphics from the Low resolution GFS 00Z.

And some more plotted GFS data (yes I was bored on a Saturday evening ). Basically, the Polar vortex trying its best at a quick recovery in the upper strat.

Zonal means.

Best regards.

Edited January 19, 2013 by Recretos

[damianslaw]

Presently Damian the mid stratosphere has warmed with the vortex being displaced and split. This has left mean negative zonal winds with two vortex centres - one over Canada, the other over Siberia.

The canadian vortex is forecast to be destroyed by a further warming at 10 hpa. Look at the profile - the stratosphere is completely dominated by a ridge where normally the strong vortex is present.

So where does that lead us tropospherically? Well to get an idea of this we need to look at the base of the stratosphere at 100hPa. Here the Canadian vortex almost becomes a 'free agent' no longer driven from above. Both the GFS and the ECM suggest that the residual Canadian vortex remnants will try and link up with the stronger Siberian counterpart. at T=240. A large ridge dominates the rest of the NH at this level - very unusual but entirely in line with the SSW.

This translates to a centrally placed Arctic ridge at 500 hPa.

and at this point the vortex is very disturbed across the NH. The transfer of energy across the Atlantic is entirely in line with the upper vortex repositioning, however, we have already seen the models overestimate this transfer of energy once in the last week. There is also the strong possibility that once the Canadian vortex demise is calculated there still remains the possibilty of strong NH blocking. The pattern above leaves a very negative AO signature - continuing the theme from just after the beginning of the SSW.

If the models have overestimated the surge of the v residual vortex energy across the Atlantic, then the Siberian vortex is waiting in the wings to back west - an enticing prospect for cold lovers.

Many thanks for the very detailed response and it clears things up immensely. As I thought the canadian PV is about to take a battering and will try to link up with the stronger siberian PV indicative of a very disturbed PV. It all suggests strong greenland heights eventually and no steamrolling of the atlantic across the country - going by these upstream signals, I wouldn't be surprised now to see the jet force any atlantic attack on another SE trajectory just like we have now maintaining strong heights to our NE and as we move into Feb we come under the influence as you say of the siberian vortex with heights staying strong over Greenland - getting a bit carried away but such a prospect screams echo of the synoptics we saw in Dec 2010.

[chionomaniac]

Recretos, the vortex reforming strongly at the top of the strat is to be expected. It can also aid in the coming weeks - as the vortex recovery descends the negative mean zonal winds can be flushed downwards ahead of this.

[Recretos]

Yes, all clear about that. I wasnt pointing it out as an "evil omen". Just as a fact.

[chionomaniac]

Yes, all clear about that. I wasnt pointing it out as an "evil omen". Just as a fact.

Cheers for that.

[Weather-history]

Chiono

What do you make of this comment made on another site?

"In addition 10mb forecasts suggest a return to a more circumpolar vortex and marked cooling aloft in the Stratosphere, therefore it seems likely that a return to more Atlantic dominated whether will prevail"

Do you agree with this?

[chionomaniac]

Chiono

What do you make of this comment made on another site?

"In addition 10mb forecasts suggest a return to a more circumpolar vortex and marked cooling aloft in the Stratosphere, therefore it seems likely that a return to more Atlantic dominated whether will prevail"

Do you agree with this?

Eventually, yes Kevin. But the mean zonal winds aren't even forecast to return to positive until the 27th at 10hPa. That is over 20 days mean negative from SSW date. And the mean zonal winds at that level would then have to rise to average (say another 15days) - probably 20m/s in early/mid Feb, and then the increased vortex at this level would slowly propagate these increased mean zonal winds down to the troposphere - another 15 days or so. So we would be looking towards end of Feb before some sort of normality is achieved.

However, one mustn't get this confused with the current projection of the strat with the Canadian vortex positioning which could appear zonal - but without the large Greenland lowered heights.

Also I keep seeing statements suggesting that the SSW hasn't propagated down to the troposphere yet. Well, that is nonsense as well.

Here are two NH 500 hpa charts from the current ECM run:

T+24

T+192

There is massive vortex disturbance seen here due to the SSW- so anyone suggesting that there isn't propagation is wrong but they can be right in saying that the propagation hasn't contributed to a large Greenland blocking high as might have been expected. But there is still a chance of that as it is only 20th Jan.Up to this point the bulk of the raised heights tropospherically have been Pacific Arctic based.

Edited January 20, 2013 by chionomaniac

[Weather-history]

Thanks Chiono

[sebastiaan1973]

Chio, I put your comments at Dutch Website VWKforum as well. http://forum.vwkweb.nl/chatbox/phpBB2/viewtopic.php?f=2&t=13188&p=123734#p123734

And the Danish 'UKMO' have some information about the SSW as well placed at their website! http://www.dmi.dk/dmi/den_kolde_vinter_kommer_oppefra

If the models have overestimated the surge of the v residual vortex energy across the Atlantic, then the Siberian vortex is waiting in the wings to back west - an enticing prospect for cold lovers.

Please tell me more about this. How does this work?

[bluearmy]

Please tell me more about this. How does this work?

sebastian, chio is merely saying that if the energy from the west (decaying canadian vortex) is overstated by the models, then heights will rise somewhat to our west/northwest. if you look to our ne, you will see the siberian vortex looking for somewhere to send its energy. as it stands, without any height rises to our nw, that cant really happen.

[chionomaniac]

Chio, I put your comments at Dutch Website VWKforum as well. http://forum.vwkweb....=123734#p123734

And the Danish 'UKMO' have some information about the SSW as well placed at their website! http://www.dmi.dk/dm..._kommer_oppefra

Please tell me more about this. How does this work?

Thanks for that Seb.

Ba has explained my thoughts well regarding the backing west - obviously not the form horse as it stands.

[Catacol]

If the models have overestimated the surge of the v residual vortex energy across the Atlantic, then the Siberian vortex is waiting in the wings to back west - an enticing prospect for cold lovers.

Agree Chio, though as I just posted over on the model thread I would feel a lot happier if any of the models started to pick up on this. I have that horrible back of the neck itchy feeling that the Canadian vortex will empty into the atlantic and the Siberian centre sit stationary or even back further east. That means a problem for height rises, and the eventual end of our SE flow. I hope my mind is just exaggerating the appearance of current op modelling, but December is still fresh in the memory (though to be fair strat forecasts back then did not suggest substantive height rises to the north, as you were quick to point out yourself in late November...)

[Catacol]

sebastian, chio is merely saying that if the energy from the west (decaying canadian vortex) is overstated by the models, then heights will rise somewhat to our west/northwest. if you look to our ne, you will see the siberian vortex looking for somewhere to send its energy. as it stands, without any height rises to our nw, that cant really happen.

Agreed. Fingers massively crossed for overmodelling of the canadian vortex progression. Back in December if anything this process was under modelled...

[Tamara]

Taking into account it is a decaying section of vortex, the fact that it is decoupled from/and due to no main driving force of a polar westerly 'wheel' so to speak, and also taking into account natural model eastward bias at a given range - it seems highly likely to me that the atlantic and residual vortex strength is being over modelled and we should make southward and westward adjustments accordingly.

Cat H - the situation is very different to December. The energy over the atlantic was driven by a (relatively) stronger and more integral vortex - even though back then it was still stretched, weaker and not as not organised as it usually is in the absence of favourable stratospheric conditions.

I may not have understood this properly, but wouldn't Phase 8 MJO also support high pressure over Greenland as a switch from the Pacific? This phase movement from 7 to 8 happening in tandem with the destruction of the Canadian vortex to finally facilitate the development of pressure rises to the NW?

Edited January 20, 2013 by Tamara Road

[Catacol]

I may not have understood this properly, but wouldn't Phase 8 MJO also support high pressure over Greenland as a switch from the Pacific? This phase movement from 7 to 8 happening in tandem with the destruction of the Canadian vortex to finally facilitate the development of pressure rises to the NW?

Yes - I agree in theory... but back in December the vortex transferred completely to Siberia and there was still enough energy left to hold sway in the atlantic for a fortnight but not enough energy to fire it all the way through to Europe. The result then was that we lost our low heights to the south too.

Here again we have a relatively depowered vortex segment, this time depowered due to strat assault, and modelling has it sitting hard and fast over the atlantic. CPC anomaly chart show the same cool to cold zonality picture out to 14 days at present. Siberian shard still showing no op run progression to drop towards us.

I'm in pessimistic mood as it is... but I am just nervously smelling a developing situation that might see cold rain as the dominant factor from the end of this week... unless we can get that residual energy to fire far enough east to allow height rises behind and then it is game on. Either that or we need it to die in situ... but that looks even less likely at present.

[lorenzo]

Snippet from eumetsat including meto talking about satellite data assimilation and resolution.

http://www.eumetsat.int/Home/Main/News/Features/827337?l=en

[iceicebaby]

No SSW effect aight?

[iceicebaby]

Today it looks a bit different.

Edited January 21, 2013 by iceicebaby

[AWD]

Looks like its topped out and maintaining at around -50c;

[chionomaniac]

Stratospherically we are still seeing a NH pattern dominated by the recent SSW. Contrary to some opinions, this has downwelled from the mid stratosphere and affected the troposphere. It is always hit and miss how and where the SSW can have knock on effects in the troposphere and it appears that we have been lucky to see the split vortex favourably positioned to prevent the jet stream powering through during the two week mid January period.

However, that is about to change as further warming of the stratospheric Canadian vortex which allows it's tropospheric counterpart to break free. West to east momentum initially is set to carry this across the Atlantic to its Siberian counterpart as can be seen in this 30 hPa chart.

As this occurs there will be a corresponding increase in Atlantic mobility allowing the westerlies to reach the UK rather than be held at bay. The stratospheric vortex even though weak will be positioned on the Atlantic sector meaning a far less meridional jet stream whereas the Pacific sector will have a far more disturbed flow due to the upper ridge holding strong. This pattern will be as of a direct consequence to recent stratospheric events - but the wheel of fortune will be dropping off the meridional cold flow elsewhere in the NH.

So the main question that everyone is asking is will we likely to see a pattern re- emerge that can bring back the cold and blocking to our shores. And the answer is not immediately but definitely not no!

With the weakened vortex conditions likely to persist for a period of time then it is only a matter of time before realignment occurs in line with the MJO and GWO.

The stratospheric forecasts during the next 10 days right up to 10 hPa are showing and will show signs of increased fluctuations in the exact position of the vortex.

There are signs of another split occurring around day 10 and this will need to be watched carefully.

If this does occur then we could quite easily see the door to returning cold opened back up again. I think we will need to keep an eye on the strat forecasts very closely in this period.

Edited January 22, 2013 by chionomaniac

[Rollo]

Hi Chio,I read every one of your posts and get very cross when at the first signs of anything mild showing up certain members start doubting, at no time did you or GP ever say that continuous cold was a given and indeed you both went on at length writing that nothing was certain,your input has been fantastic and please ignore the doubters and continue your good work.

[Methuselah]

If GP and Chio have ever claimed that a SSW guarantees a re-run of 1947, I've certainly never seen it...

[Ladyofthestorm]

Hi Guys, I have been reading your posts intently for the past four weeks or so and it can make some really interesting reading. I have a hunch that after the mild spell lasting Approx 7-10 days thecold will come back.Is there anything in the SSW forecasts that could support my hunch? PS Chino your a weather god! lol

[Weather-history]

Hello Chiono

Any thoughts to how next winter might pan out stratospherically? I might have a memory fault but I do recall you making a general idea on how the next season might pan out.

[chionomaniac]

Hi Guys, I have been reading your posts intently for the past four weeks or so and it can make some really interesting reading. I have a hunch that after the mild spell lasting Approx 7-10 days thecold will come back.Is there anything in the SSW forecasts that could support my hunch? PS Chino your a weather god! lol

Thanks Lots.

I think that you are right. There is a lot of uncertainty in the strat forecasts presently - no two are the same out at day 10. Especially with the modelling on energy crossing the Atlantic at lower and mid strat levels. What should this tell you? If you can't trust the strat output presently and that this is having a large bearing on the trop output, then don't trust that either. I wouldn't be surprised to see a GH pop out days 12-15 as per Cohen because longer start forecasts are beginning to shift that ridge around away from the Pacific centre.

Hello Chiono

Any thoughts to how next winter might pan out stratospherically? I might have a memory fault but I do recall you making a general idea on how the next season might pan out.

Not yet!!!

(other than less favourable west based QBO)