Stratosphere Temperature Watch 2012/2013

[summer blizzard]

I alway's wondered why the PV sets up shop over Greenland, is it something that has always happened?

Normally its directly over the pole, it just so happens that Greenland is pretty close.

In addition to that, there is a strong thermal gradient present in the Atlantic due to the Gulf Stream, so when the polar vortex forces the Jet Stream on a track which intersects with the Gulf Stream near Iceland you get a strong cyclonic pressure gradient.

[SteveB]

Normally its directly over the pole, it just so happens that Greenland is pretty close.

In addition to that, there is a strong thermal gradient present in the Atlantic due to the Gulf Stream, so when the polar vortex forces the Jet Stream on a track which intersects with the Gulf Stream near Iceland you get a strong cyclonic pressure gradient.

Thanks for explaining.

[MattH]

The general cooling trend looks set to continue according today's forecast models;

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t10_nh_f00.gif

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t10_nh_f240.gif

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=30&forecast=all&lng=eng#fig11

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=10&forecast=all&lng=eng#fig11

The zonal mean state from the ECMWF model out to 240hrs introduces sub -70C temps near 30hPa/20hPa above 80N as well which isn't particularly good to see;

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=t&lng=eng

Some warming is still evident at lower altitudes but, again this needs to propagate to higher altitudes;

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t50_nh_f216.gif

Also I've attached the AO and NAO GFS ENS prediction graphs. Clearly and of importance is the AO prediction in particular which clearly shows a trend towards more neutral conditions if not perhaps beginning to become more positive into and beyond the opening week of November.

I have a distinct feeling that the next 7 to 14 days will see quite a direct progression towards a more cyclonic/zonal/mobile spell of weather with a likely trend away from the meridional and blocked pattern of present and within the coming days. Clearly, and as a I mentioned in my previous post, this doesn't write off early winter, but it's a progression which if continues to go uninterrupted through November would likely lead to an increased risk of December being generally milder/more unsettled etc.

Time'll tell...

Matt.

[Cheshire Freeze]

The general cooling trend looks set to continue according today's forecast models;

http://www.cpc.ncep...._t10_nh_f00.gif

http://www.cpc.ncep....t10_nh_f240.gif

http://wekuw.met.fu-...l&lng=eng#fig11

http://wekuw.met.fu-...l&lng=eng#fig11

The zonal mean state from the ECMWF model out to 240hrs introduces sub -70C temps near 30hPa/20hPa above 80N as well which isn't particularly good to see;

http://wekuw.met.fu-...l&var=t&lng=eng

Some warming is still evident at lower altitudes but, again this needs to propagate to higher altitudes;

http://www.cpc.ncep....t50_nh_f216.gif

Also I've attached the AO and NAO GFS ENS prediction graphs. Clearly and of importance is the AO prediction in particular which clearly shows a trend towards more neutral conditions if not perhaps beginning to become more positive into and beyond the opening week of November.

I have a distinct feeling that the next 7 to 14 days will see quite a direct progression towards a more cyclonic/zonal/mobile spell of weather with a likely trend away from the meridional and blocked pattern of present and within the coming days. Clearly, and as a I mentioned in my previous post, this doesn't write off early winter, but it's a progression which if continues to go uninterrupted through November would likely lead to an increased risk of December being generally milder/more unsettled etc.

Time'll tell...

Matt.

Aye it's all looking rather grim IMO and sods law that as soon as we get the other variables conducive to a potentially cold winter, the strat looks like digging its heels in.

December is the best month for cold IMO...... short days and the promise of 2 more months of winter in front of us. The thought of a zonal December doesn't exactly fill me with joy TBH

Edited October 22, 2012 by CreweCold

[shedhead]

Good post Matt, though not nescessarily good news.....clearly you have never read 'How To Make Friends And Influence People'....

[Cheshire Freeze]

Good post Matt, though not nescessarily good news.....clearly you have never read 'How To Make Friends And Influence People'....

I think the people in the winter thread will have to face facts sooner or later. There's been a lot of separation from reality in there just lately!

[johnholmes]

thanks for the realistic post Matt as you see it.

BEFORE folks read this and rush into print no more cold Matt says so PLEASE read what he says, PLEASE read if you have not already done so the initial post with links explaining about this complex subject.

Again I'll say to those with little knowledge yet of this complex subject PLEASE learn to walk before you try to run. I'm past the crawling stage but certainly not confident enough to contemplate running just yet!

[shedhead]

I think the people in the winter thread will have to face facts sooner or later. There's been a lot of separation from reality in there just lately!

No more than normal from what I've seen, but the predicted cold blast has kicked things off a good deal earlier this season, that's for sure. As for the outlook, still some unseasonally cold weather to come, but the evidence is certainly beginning to stack up now on a return to a milder, zonal pattern into Nov....like we need more rain!! Edited October 22, 2012 by shedhead

[BLAST FROM THE PAST]

Yes the pattern may become more mobile, and I think that will occur. However, it doesn't have to be mild. Is one thinking of LPs travelling SW to NE through the GIN corridor ? Mild zonal, cold zonal, blocked...Lets see what develops,...

BFTP

[johnholmes]

the 500mb anomaly charts do not currently suggest anything mild into the start of November, just a hint perhaps on the last NOAA with a largish -ve area 40N 40W that this MIGHT develop.

Too early in my view to suggest it WILL happen.

[sebastiaan1973]

Thanks Matt for this overview. Altough not an expert, I suspect we have to wait a little longer. Chio showed us the theory of Cohen with his Snow Advance Index. In that perspective things look quite well in Siberia. The effect of this snowfall will become clear in the coming weeks.

[Glacier Point]

The debate about where we currently sit should firmly revolve around the QBO / solar flux.

We are away from the solar minima and in a second cold season east QBO. That will lead to a cooling stratospheric profile. But here's the deal, with this type of QBO, especially going into a second cold season and solar activity relatively low, this is tantamount to a ticking time bomb. There is a high probability this winter of one or more warming events. Our nearest comparison year, 1968, had its first warming in late November.

For reference, I've collected 21 October ozone data from 2012, 2011 and 2009 to give us a fix on where we stand currently:

Not bad, not as expansive as 2009 but certainly better than 2011. The relaxation of the warming in the southern hemisphere should assist the BDC make its contribution more felt in the NH in the coming weeks.

Also, note the rapid increase in Eurasian snowcover that has happend and will continue to consolidate with the projected pattern for the next 10 days. That gives every chance that zonal wind flow will be disriupted and eddy fluxes will begin to develop over Siberia and into the North Pacific. Already I'm seeing first indication of falling heights across the North Pacific which begins to initiate the longwave response across the NH - look out for increasing wave 1 activity in the coming weeks which will persist strong +ve heights to the north and NE. We should expect to see low pressure in the Atlantic but more with the jet orientated NW-SE or even more meridional. Ideally we want this North Pacific low and a ridge over eastern Europe to set in train a warming event.

Incidentally, GFS and ECM long range 30hPa temperature forecasts maintain -70C or -75C values for early November over the Pole, which is average or slightly above average for that time of year.

[Isolated Frost]

The debate about where we currently sit should firmly revolve around the QBO / solar flux.

We are away from the solar minima and in a second cold season east QBO. That will lead to a cooling stratospheric profile. But here's the deal, with this type of QBO, especially going into a second cold season and solar activity relatively low, this is tantamount to a ticking time bomb. There is a high probability this winter of one or more warming events. Our nearest comparison year, 1968, had its first warming in late November.

For reference, I've collected 21 October ozone data from 2012, 2011 and 2009 to give us a fix on where we stand currently:

Not bad, not as expansive as 2009 but certainly better than 2011. The relaxation of the warming in the southern hemisphere should assist the BDC make its contribution more felt in the NH in the coming weeks.

Also, note the rapid increase in Eurasian snowcover that has happend and will continue to consolidate with the projected pattern for the next 10 days. That gives every chance that zonal wind flow will be disriupted and eddy fluxes will begin to develop over Siberia and into the North Pacific. Already I'm seeing first indication of falling heights across the North Pacific which begins to initiate the longwave response across the NH - look out for increasing wave 1 activity in the coming weeks which will persist strong +ve heights to the north and NE. We should expect to see low pressure in the Atlantic but more with the jet orientated NW-SE or even more meridional. Ideally we want this North Pacific low and a ridge over eastern Europe to set in train a warming event.

Incidentally, GFS and ECM long range 30hPa temperature forecasts maintain -70C or -75C values for early November over the Pole, which is average or slightly above average for that time of year.

Very interesting GP- would also like to see many note it. You did comment on 'this type' of QBO, I'm intrigued as to what this type is. Would it not be a case of a simple east QBO?

The point you make about snowcover affecting the zonal wind flow is very interesting to me, as I wouldn't expect a major tropospheric reaction away from the immediate areas? Would such a rise in NH snowcover enhance the likelyhood of meridional wind flow, and how may I ask?

[Glacier Point]

The profile of this QBO since its development last year mirrors a few in the last 50 years. There is a discernible difference in east QBOs away from solar minima in how they perpetuate across the equator and 10N, depending on thier longevity. For QBOs lasting this long, there is a trend towards light to moderate zonal wind increase in the autumn across 70N, followed by interuptions to this during November, December and January - 1968 being a classic example.

For snowcover, see above papers. The basic gist being:

- sudden expanse in snowcover develops a pool of cold air which acts like a brick wall to the zonal flow;

- tropospheric response is for frictional torques to develop 40N;

- poleward eddy flux follows as a response;

- anticyclones develop on poleward flank of the eddy, initiating Rossby Wave train and alteration of entire NH longwave pattern - Aleutian low the notable one;

- in turn the tropospheric longwave pattern re-inforces itself with wave breaking into the stratosphere and decceleration of the polar night jet.

[Isolated Frost]

Superb! Such a long and rather complex process leading to a change in the tropospheric longwave pattern but it really is worth knowing the development of what we see on NWPs, many people could take this into mind this winter.

Must note the longevity of this east-based QBO is indeed noteworthy, and the composites to such an event do point towards a more meridional tropospheric pattern towards the early winter.

[Frozen Britain]

The profile of this QBO since its development last year mirrors a few in the last 50 years. There is a discernible difference in east QBOs away from solar minima in how they perpetuate across the equator and 10N, depending on thier longevity. For QBOs lasting this long, there is a trend towards light to moderate zonal wind increase in the autumn across 70N, followed by interuptions to this during November, December and January - 1968 being a classic example.

For snowcover, see above papers. The basic gist being:

- sudden expanse in snowcover develops a pool of cold air which acts like a brick wall to the zonal flow;

- tropospheric response is for frictional torques to develop 40N;

- poleward eddy flux follows as a response;

- anticyclones develop on poleward flank of the eddy, initiating Rossby Wave train and alteration of entire NH longwave pattern - Aleutian low the notable one;

- in turn the tropospheric longwave pattern re-inforces itself with wave breaking into the stratosphere and decceleration of the polar night jet.

What was the stratospheric profile like in 1968, GP?

I assume that it didn't start cold, as it did last year?

As we saw last winter, it is very difficult for the stratosphere to recover if it starts cold

The winters of 09/10 and December 2010 were so good because there were a series of warmings in the strat before December - this may not be the case this year?

[Cheshire Freeze]

The debate about where we currently sit should firmly revolve around the QBO / solar flux.

We are away from the solar minima and in a second cold season east QBO. That will lead to a cooling stratospheric profile. But here's the deal, with this type of QBO, especially going into a second cold season and solar activity relatively low, this is tantamount to a ticking time bomb. There is a high probability this winter of one or more warming events. Our nearest comparison year, 1968, had its first warming in late November.

For reference, I've collected 21 October ozone data from 2012, 2011 and 2009 to give us a fix on where we stand currently:

Not bad, not as expansive as 2009 but certainly better than 2011. The relaxation of the warming in the southern hemisphere should assist the BDC make its contribution more felt in the NH in the coming weeks.

Also, note the rapid increase in Eurasian snowcover that has happend and will continue to consolidate with the projected pattern for the next 10 days. That gives every chance that zonal wind flow will be disriupted and eddy fluxes will begin to develop over Siberia and into the North Pacific. Already I'm seeing first indication of falling heights across the North Pacific which begins to initiate the longwave response across the NH - look out for increasing wave 1 activity in the coming weeks which will persist strong +ve heights to the north and NE. We should expect to see low pressure in the Atlantic but more with the jet orientated NW-SE or even more meridional. Ideally we want this North Pacific low and a ridge over eastern Europe to set in train a warming event.

Incidentally, GFS and ECM long range 30hPa temperature forecasts maintain -70C or -75C values for early November over the Pole, which is average or slightly above average for that time of year.

Nice one Stewart So you don't see the dip below average temps in the strat too much cause for oncern then? I think you may have allayed a few fears tonight!

[kate1]

Many thanks, Glacier Point, for an excellent and extremely informative post - I can't pretend to understand all of it, though I'm trying my best, but I'm sure you have calmed a few frazzled nerves (mine included!). I particularly like the sound of that 'ticking time bomb'!

Edited October 22, 2012 by kate1

[chionomaniac]

Incidentally, GFS and ECM long range 30hPa temperature forecasts maintain -70C or -75C values for early November over the Pole, which is average or slightly above average for that time of year.

I don't know what data you are using Stewart but I reckon that this is slightly below for November. The 30 hPa average temperature for the whole of November is -68.6ºC. In fact the Berlin Free University consider below -70ºC as a cold monthly mean.

http://www.geo.fu-be...pole/index.html

Oh edit, sorry, I could be using he 30 year data here.

The 57 year data has the mean at -70ºC with a cold monthly mean as -72ºC. That shows how cold the strat has become over the last 27 years!

November 1968 had a monthly mean of -63ºC with a CW.

Edited October 22, 2012 by chionomaniac

[bluearmy]

I don't know what data you are using Stewart but I reckon that this is slightly below for November. The 30 hPa average temperature for the whole of November is -68.6ºC. In fact the Berlin Free University consider below -70ºC as a cold monthly mean.

http://www.geo.fu-be...pole/index.html

the jma shows -70c as the average at the beginning of nov and then dropping slowly after that. i guess we have much time in hand before winter is due to arrive in order to see if stewart's thoughts are going to be proven right. it may try everyones patience but it may be another two to three weeks at least before we get a good handle on this winters strat behaviour and response to the temps within it, top to bottom.

[chionomaniac]

the jma shows -70c as the average at the beginning of nov and then dropping slowly after that. i guess we have much time in hand before winter is due to arrive in order to see if stewart's thoughts are going to be proven right. it may try everyones patience but it may be another two to three weeks at least before we get a good handle on this winters strat behaviour and response to the temps within it, top to bottom.

Just adjusted, ba.

Note- The 30hPa November temp for 2009/10 is -64ºC for those who are wondering about that temp in other threads!

Edited October 22, 2012 by chionomaniac

[BLAST FROM THE PAST]

GP

I take it you are referring to autumn 1968 so winter 68/9?

BFTP

[TEITS]

Im going to eat some humble pie and apology to CH because after spending ages reading through some archive stratosphere threads, im just amazed at how accurate CH has been. I read through the 2009, 2010,2011 threads and the biggest mistake I made was I didn't read all the posts until tonight.

Here is a snippet of what CH said on November14th 2010.

"Looking at the phase of the GWO I believe that we are now going to experience a strong negative asian mountain torque event which again is going to cause another wave number 2 to break into the stratosphere. This is likely to cause another warming of the stratosphere in around 15 days time before it has had a chance to cool down from the present warming. This is likely to cause further disturbances with the tropospheric vortex right up until the middle of December, with phases of Northern blocking right up until this time and possibly Christmas."

Well after reading the above and knowing what occured at the end of Nov/Dec I can only admire this post from CH.

So my sincere apologies to CH because I was definitely wrong in my posts on the winter thread. I strongly urge members to read these archive Strat threads because when you read all the posts like I have done it not only improves your knowledge but makes following this current thread even more important.

[chionomaniac]

I thank you Dave and will also apologise back.

I acknowledge your assertion that we do not know enough about the stratosphere and that there are certain areas that are hit and miss. Most of these lie in the period after a strong warming event and whether or not this can successfully propagate down to the troposphere and then affect our small island after that. However, we have also learnt a lot from analysing the behaviour of the stratosphere and its interaction with the troposphere these last few years. And, when something occurs that we did not expect, we have sought out answers why to help us the next time.

It will be good to have you on board, Dave.

[sebastiaan1973]

Comparison between 22nd of october 2009 & 2012. There seems to be somewhat more snow in 2012. In the next days there will fall lot's of snow in the western part of Siberia.