Stratosphere Temperature Watch 2011/2012

[cyclonic happiness]

The Stratosphere seems to be around record lows - is there any historic data showing a trend when the stratosphere has been this low?

I'm not the one to ask, but just thought I'd say welcome to the forum, you come just at the right time with snow on the way!!!

Sit back and enjoy the madness

[chionomaniac]

The Stratosphere seems to be around record lows - is there any historic data showing a trend when the stratosphere has been this low?

Have a look here:

http://acd-ext.gsfc.nasa.gov/Data_services/met/ann_data.html

[Catacol]

Chio - can you help me with that graph? It is an average over a wide range of latitude and doesnt seem to show the warming that I understood had occurred this time last year to help destabilise the vortex. Is it much use as a graph with such a wide range of latitude? Should we not be looking at temperatures in more precise areas, and seeing how tropospheric trends emerge from more specific upper atmospheric conditions?

Or perhaps I am barking up the wrong tree. Is such a wide average useful?

Cheers

Al

[chionomaniac]

Chio - can you help me with that graph? It is an average over a wide range of latitude and doesnt seem to show the warming that I understood had occurred this time last year to help destabilise the vortex. Is it much use as a graph with such a wide range of latitude? Should we not be looking at temperatures in more precise areas, and seeing how tropospheric trends emerge from more specific upper atmospheric conditions?

Or perhaps I am barking up the wrong tree. Is such a wide average useful?

Cheers

Al

Hi Al,

You select the criteria that you want to look at and make your own chart.

For instance if I wanted to see what the stratospheric temperatures were in winter 2008/ 2009 at 30hPA between 60-90ºN then I would select the appropriate info in the drop down boxes and come up with this:

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t60_90n_30_2008_merra.pdf

A pretty impressive SSW that year!

[Catacol]

Ah - apologies; I was being dull. Thanks...

And yet I still cant see the warm stratosphere in autumn last year that is supposed to have caused the vortex to destabilise and allow that chunk of very cold air to dive over us in late December. Am I remembering that wrong? Was there not a warm stratosphere last autumn?

Edited December 6, 2011 by Catacol_Highlander

[chionomaniac]

Ah - apologies; I was being dull. Thanks...

And yet I still cant see the warm stratosphere in autumn last year that is supposed to have caused the vortex to destabilise and allow that chunk of very cold air to dive over us in late December. Am I remembering that wrong? Was there not a warm stratosphere last autumn?

Last year the stratosphere was a lot warmer late October into early November - look at the 30 hhPa chart. This helped considerably later into November as the tropospheric vortex was reduced and local wave breaking split the vortex up into the mid stratosphere. This will have had the knock on effect of delaying the background signal developing with the cooling of the stratosphere. So before the stratosphere had cooled sufficiently it was still vulnerable to another local wave break which is exactly what occurred mid December.

[weatherjunkie]

What would some signs be of wave breaking? I know we have to look at geopotential waves 1 and 2, but what other sources can we look at to determine the possibility of wave breaking?

[MattH]

Just a quick one but I've ploughed through all the usual links and charts and the end result at the moment IMO is still nothing of any worth and a case of 'as you were' to be honest...

The scenario 'up north' looks very cold indeed with a large and well established

PV

with some very low heights within the mid and upper levels indicating the deep cold evident that is simply just locked up there. It looks as though it's going to be a very tedious month does December and whilst I guess a SSW can occur at relatively short notice, the usual indicators aren't pointing towards anything of any worth. It is of worth to highlight what has been mentioned previous however, just for the record, and that is colder conditions can obviously still be achieved at times, but not on any significant scale as per last December or the winter previous to that. Clearly the last few days indicate that potential/risk.

I'm really in two minds about how this winter may pan out now to be honest. Clearly we are only just leaving behind the first week of December and generally it's been far from mild and the models don't really indicate the dreaded scenario of high pressure to the SE and low pressure to the NW leading to relentless mild SW'lies and temps near 10C with drizzle and hill fog etc. That being said the scenario across the pole looks 'locked in' for the time being and clearly to get a change or reversal of fortunes is going to take time and whilst a large chunk of winter still remains it may well be a case of patience is a virtue, but equally in the world of meteorology and weather types, good things

don't

always come to those who wait, unfortunately!

Thoughts anyone?...disagree/agree?...

Regards, Matt.

[cyclonic happiness]

Just a quick one but I've ploughed through all the usual links and charts and the end result at the moment IMO is still nothing of any worth and a case of 'as you were' to be honest...

The scenario 'up north' looks very cold indeed with a large and well established

PV

with some very low heights within the mid and upper levels indicating the deep cold evident that is simply just locked up there. It looks as though it's going to be a very tedious month does December and whilst I guess a SSW can occur at relatively short notice, the usual indicators aren't pointing towards anything of any worth. It is of worth to highlight what has been mentioned previous however, just for the record, and that is colder conditions can obviously still be achieved at times, but not on any significant scale as per last December or the winter previous to that. Clearly the last few days indicate that potential/risk.

I'm really in two minds about how this winter may pan out now to be honest. Clearly we are only just leaving behind the first week of December and generally it's been far from mild and the models don't really indicate the dreaded scenario of high pressure to the SE and low pressure to the NW leading to relentless mild SW'lies and temps near 10C with drizzle and hill fog etc. That being said the scenario across the pole looks 'locked in' for the time being and clearly to get a change or reversal of fortunes is going to take time and whilst a large chunk of winter still remains it may well be a case of patience is a virtue, but equally in the world of meteorology and weather types, good things

don't

always come to those who wait, unfortunately!

Thoughts anyone?...disagree/agree?...

Regards, Matt.

The kind of set up we're in at the moment is probably caused by the cold stratosphere 'very cold zonality', in this kind of set up, certain parts of the UK could get enormous dumps of snow!

Just because we're not in an easterly regime doesn't mean it's the be all or end all for cold spells, this 'cold spell' is lasting beyond a week or more by the looks of the models.

I just hope the temperatures stay cold enough to keep and snow that falls.

[BLAST FROM THE PAST]

My view is that in the previous perturbation cycle a cold stratos and PV as we have now would have lead to the dreaded 3000 mile SW'ly scenario and the deep cold would be locked in without spilling south. However, currently we see that even with the stratos in serious cold territory and apparent unfavourable conditions we see that cold is still extending out from the arctic region and this is why I am more than hopeful that it won't remain locked up for too long let alone most of the winter.

BFTP

[chionomaniac]

Someone give the berlin site server a kick! Must be a massive warming that has caused it to fail!

Matt- I can understand the thoughts regarding possible two minds regarding this winter - I was relying on the possiblility of a SSW to throw the strong PV out of kilter to allow Northern Blocking later in winter. I still feel that that is likely to happen, more so looking at GP's composites in the model thread yesterday evening. I don't believe that cold zonality will last into the new year and from now on I am on a watch for a potential SSW. I don't think that cold zonality ever delivers for the southern third of the country, so on a personal note whereas I love the current synotic set up and dramatic weather further north I would still want a piece of the action myself.

weather junkie - I think it is very difficult to predict any wave breaking events - most waves don't break into the stratosphere and those that do often get absorbed quickly. Certainly if the strong Siberian blocking occurs then we may get some wave disruption either locally into the centre of the vortex itself or perhaps more remotely from an Asian MT event and this would be over the top - circling the edge of the vortex before entering at the top and propagating downwards.

[chionomaniac]

Further to my earlier post I have looked at today's GFS charts and I have to say I am surprised by what I see. It appears that the elongation of the vortex from the Atlantic to Pacific is now continuing to such an extent that a split seems to be occurring up to the 70 hPa level. This in my opinion will be due to local upwelling wave activity from the troposphere into the stratosphere but I am surprised to see this with a strong vortex scenario.

It is still early days and I have seen these early splits come and go in the forecasts but worth mentioning nonetheless.

What is the ECM hiding?

[greybing]

Further to my earlier post I have looked at today's GFS charts and I have to say I am surprised by what I see. It appears that the elongation of the vortex from the Atlantic to Pacific is now continuing to such an extent that a split seems to be occurring up to the 70 hPa level. This in my opinion will be due to local upwelling wave activity from the troposphere into the stratosphere but I am surprised to see this with a strong vortex scenario.

It is still early days and I have seen these early splits come and go in the forecasts but worth mentioning nonetheless.

What is the ECM hiding?

What is the upshot of this.Potential scenarios?

[chionomaniac]

What is the upshot of this.Potential scenarios?

A substantial split in the polar vortex will tend to send polar air flooding southwards and probably allow room for a high latitude block to form. In the case here I don't think the UK would be best positioned to gain from it where it to even occur. Whether there is cold air to tap in further down the line would remain to be seen.

The most crucial aspect would be that the PV is vulnerable to this so soon. This is not something that I was expecting at this point in winter - so it could just be a false alarm!

[weatherjunkie]

Someone give the berlin site server a kick! Must be a massive warming that has caused it to fail!

Matt- I can understand the thoughts regarding possible two minds regarding this winter - I was relying on the possiblility of a SSW to throw the strong PV out of kilter to allow Northern Blocking later in winter. I still feel that that is likely to happen, more so looking at GP's composites in the model thread yesterday evening. I don't believe that cold zonality will last into the new year and from now on I am on a watch for a potential SSW. I don't think that cold zonality ever delivers for the southern third of the country, so on a personal note whereas I love the current synotic set up and dramatic weather further north I would still want a piece of the action myself.

weather junkie - I think it is very difficult to predict any wave breaking events - most waves don't break into the stratosphere and those that do often get absorbed quickly. Certainly if the strong Siberian blocking occurs then we may get some wave disruption either locally into the centre of the vortex itself or perhaps more remotely from an Asian MT event and this would be over the top - circling the edge of the vortex before entering at the top and propagating downwards.

Yeah, I remember quite a few cases where there was a significant Asian MT/Siberian blocking event followed by -AO/-NAO. Thank you for the response.

Edited December 7, 2011 by weatherjunkie

[MattH]

Is there anything in this chart perhaps?...

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf30f240.gif

Compared with recent days this does seem to be a relatively new development in terms of a zone of higher temperatures across far northern regions of the Pacific. Could this signal for higher temperatures become entrained into higher latitudes?...

Clearly there is still a highly established PV near Svalbard and no signs of any splitting near 240hrs, but could we be onto something?...

M.

[chionomaniac]

Is there anything in this chart perhaps?...

http://wekuw.met.fu-...ecmwf30f240.gif

Compared with recent days this does seem to be a relatively new development in terms of a zone of higher temperatures across far northern regions of the Pacific. Could this signal for higher temperatures become entrained into higher latitudes?...

Clearly there is still a highly established PV near Svalbard and no signs of any splitting near 240hrs, but could we be onto something?...

M.

Yes, ECM says no to split.

There is very little on this chart, Matt, but that is the exact thing that I look for. The remote warmings can be tracked entering the vortex. The GFS has also suggested a slight warming on the 30 hPa forecasts over the last few days as well, but compared to warmings that we have seen over the last few years nothing of any significance. I suspect that the small Pacific warmings seen at 30hPa this autumn are a response to increased ozone which looks to be more concentrated here than at other heights in the stratosphere.

[lorenzo]

Any update Chiono?? Split Vortex? Mild Intervention ? Warming? Migration to a flatter pattern orientated towards pacific?

Many questions I know, main one I would like to know is what created this pattern that seemingly wants to exist of LP after LP being ejected into the Atlantic at Mid Latitudes.. Is this something we have seen before or is it an anomaly of the entrenched vortex decay and movement>

[DAVID SNOW]

Houston.....................

We have lift off.

[Great Plum]

Houston.....................

We have lift off.

Please explain!

[Azores Hi]

Please explain!

Possibly refering to this??

A small warming at the 30hPa level, could this be what we have been waiting for? Certainly the most significant warming we have seen so far this season, hopefully it continues to rise!

[sebastiaan1973]

I think the recent rising of the temperature is just temporarily (like Chio stated earlier in this page) and he uses not this picture, but a more broader view.

Anybody a clue why this year the atmosphere is so extremely cold?

[Glacier Point]

The transition of the QBO from west to east allied to an uptick in solar activity and interfrence of the Brewer Dobson Circultation during the summer (following a strong final warming of the polar stratosphere in April have all lead us to where we are now, something that was anticipated back in October.

However, green shoots starting to emerge. This is not a forecast of a stratospheric warming.

Mean zonal winds have decreased in the last 48 hrs to average levels in the middle and upper stratosphere. We also see the ECM continuing to toy with the idea that 10hPa tempeatures are trending back towards normal (this might be of interest to monitor the impacts of a relative increase from such a low base). Heat flux at 60N 30hPa is approaching a medium level and 30hPa temperatures whilst forecast to remain static, relative to the cooling mean, will actually show a slight increase.

When we next get a westerly wind burst in the troposphere (estimated at latter 1/3 of December), and potential Asian Mountain Torque off the back of it, this will be the time to take advantage of any lessening of the cooling trend.

Edited December 9, 2011 by Glacier Point

[bluearmy]

this is what has interested me for a while - given the very low temps at 30hpa, we cant really avoid a warming. does it matter what the actual temp is or is it the warming/ rate of earming that may affect the strat/trop relationship ??

[snowking]

this is what has interested me for a while - given the very low temps at 30hpa, we cant really avoid a warming. does it matter what the actual temp is or is it the warming/ rate of earming that may affect the strat/trop relationship ??

I could be wrong but I was under the impression that it was generally the thermal gradient between the polar and tropical stratosphere that determined (in part or in whole) the strength and positioning of the PV. The smaller the gradient, the weaker the vortex.

On that theme, are there any graphs out there to show the state of the tropical stratosphere? As i suppose in theory even an average polar stratosphere could lead to a disrupted vortex should the tropical stratosphere be cooler than average.

SK