Stratosphere Temperature Watch 2013/2014

[Snowman.]

Warmth increasing over America towards the end of the latest GFS run should shunt the the core back east a tad.

 

 

Just needs watching 

[Buriedundersnow]

Warmth increasing over America towards the end of the latest GFS run should shunt the the core back east a tad.

 

 

Just needs watching 

 

 

now I wonder if that may be what a candian warming looks like.

 

probably not but i'm sure we will find out as if it is it will be picked up on soon.

 

EDIT: should add I am not saying that's a Canadian warming just I am still learning and was wondering if one came along would it look like that to start

Edited November 28, 2013 by Buriedundersnow

[bluearmy]

this warming at 10 hpa on the americam side has been modelled for a while and seems to have no effect on the vortex. if you look at the current strat temps in that area, they are relatively warm. we need those warmer temps to get right into the canadian sector to cause some damage to the vortex.

[bluearmy]

yesterdays run had plenty going on towards the end of the run above 5hpa.  the ecm ens will now be seeing this activity where before they were blind.  lets hope for better extended guidance from them wrt last year should something begin to downwell.  zonal winds look pretty sustained through this run. 

[Catacol]

Strongest wave 1 activity of the season so far predicted at 10 days this morning. I wonder if this can build further...

 

[Snowman.]

yesterdays run had plenty going on towards the end of the run above 5hpa.  the ecm ens will now be seeing this activity where before they were blind.  lets hope for better extended guidance from them wrt last year should something begin to downwell.  zonal winds look pretty sustained through this run. 

Guessing you mean this?

 

[chionomaniac]

That is a 10hPa chart from the latest GFS run, Snowman. It is a temperature forecast only and does not include mean zonal winds. These can be found through the ECM link on the first post. Interesting the 10 day ECM forecast at 1hPA shows the wave distortion forecast at the top of the strat - the biggest of the season so far. Will watch this one as it may get down as far as 5-10hPa.

Edited November 29, 2013 by chionomaniac

[chionomaniac]

Furthermore to the last post it is worth demonstrating how strong the wave 1 activity has to be before we really see significant vortex displacement.

 

Looking so far this year we can see that there have been a number of bursts of stronger wave 1 activity. The strongest was at the start of the year and was responsible for the well predicted and monitored SSW in January ( see below). The second burst was not as strong but was very significant - at the start of March just as the vortex was recovering and we all know what happened after that. This autumn we have seen some smaller bursts of wave 1 activity - but nothing out of the ordinary - but I suspect that the next round will be stronger still.

 

Also included below is the mean zonal mean wind anomaly chart which demonstrates quite nicely the propagation of the negative mean zonal winds from the top of the strat to the trops - note the recharge at the start of March from the wave 1 activity.

 

 

 

 

 

 

[UV-RAY]

Furthermore to the last post it is worth demonstrating how strong the wave 1 activity has to be before we really see significant vortex displacement.

 

Looking so far this year we can see that there have been a number of bursts of stronger wave 1 activity. The strongest was at the start of the year and was responsible for the well predicted and monitored SSW in January ( see below). The second burst was not as strong but was very significant - at the start of March just as the vortex was recovering and we all know what happened after that. This autumn we have seen some smaller bursts of wave 1 activity - but nothing out of the ordinary - but I suspect that the next round will be stronger still.

 

Also included below is the mean zonal mean wind anomaly chart which demonstrates quite nicely the propagation of the negative mean zonal winds from the top of the strat to the trops - note the recharge at the start of March from the wave 1 activity.

Maybe something to keep an eye on for the later part of December perhaps. 

[Catacol]

I'm still learning... but we have tentative signs of increased wave 1 activity in 10 days time - strongest perhaps so far this autumn/winter.

 

 

This chart I believe shows the warming hitting the strat right at the top - 1hPa

 

 

 

The warming seems focused over our part of the NH. 

 

My question is this - and apologies if it is dull - if the warming STARTS in this segment of the NH then does it propogate downwards in a straight path to the trop? Or do wave 1 bursts like this "go with the flow" and pass to the east hence perhaps setting up a response at 30 hPa somewhere over Siberia?

 

(To be honest I have to say that my infantile brain has a real problem with understanding how warm air high up in the strat where wind speeds are around 20 m/s or faster doesnt just literally get scattered into the wind and blown around and around so fast that any coherent temperature differential between hemispheric areas gets lost. I guess that is why I am not an atmospheric physicist or some such... but there you go!)

 

And a second question. I note from charts such as this one:

 

 

that warming tends to be dragged polewards as it propagates downwards. What controls the rate of that movement? Is it a function of this thing "flux" that I am still getting my head around?

Edited November 29, 2013 by Catacol_Highlander

[Cloud 10]

That warming you show on the ecm also shows up on the gfs which progresses to 

this by T360 (chart flipped to a UK perspective)

 

 

 

Super-early days on this one though!

[blizzardof96]

With regard to any significant SSW occurring this winter, its looking very slim in DEC/JAN given the indices on the table this year. For +QBO, -PDO, N/- ENSO and years with the JAN SSN below 95 no significant warming's have even occurred since 1950 in DEC/JAN. In february their are a few exceptions, one begin 08-09 which had a strong East Pac ridge, definitely aiding in the wave 2 response. 00-01 is another example of this, although the PDO was neutral/positive and the QBO was transitioning from positive to negative. The common denominator in these two years is a strong Kamchatka PV lobe and bering sea/GOA ridging. Unless we see an uptick in the PDO/ENSO domains, or a quick downturn in the QBO by feb a major warming in the DJF period is going to be tough to come by. EP heat flux anoms are already starting off winter well below normal ever since the wave 1 response in late october. Our best shot will probably be a wave 2 warming in Feb if we can keep the EPO ridge consistent which becomes more likely given the +QBO/N ENSO and -EPO persistence. If this doesn't work out then their is always the FW question in March/April that should arise with a mean state similar to our current one. This SSW timing is much more favoured given the current setup and could have impacts on spring, especially with the warming ENSO region expected and a transitioning QBO index(favourable for high heights across the NAO/EPO region's).

 

Feb 2001

Feb 2009

Edited November 29, 2013 by blizzardof96

[bluearmy]

wave activity high up continues to be notable. What I am noticing is the general direction of the zonal wind strength. In the first part of the run, it is directed towards the higher latitudes but as the run progresses, this tends towards the mid latitudes to the extent that by day 10, to find a zonal wind speed in excess of 30m/s at 70N, you have to go right up to 5hpa. watch this trend as, in my experience, it would mean the northern arm of the jet more able to weaken.

[chionomaniac]

With regard to any significant SSW occurring this winter, its looking very slim in DEC/JAN given the indices on the table this year. For +QBO, -PDO, N/- ENSO and years with the JAN SSN below 95 no significant warming's have even occurred since 1950 in DEC/JAN. In february their are a few exceptions, one begin 08-09 which had a strong East Pac ridge, definitely aiding in the wave 2 response. 00-01 is another example of this, although the PDO was neutral/positive and the QBO was transitioning from positive to negative. The common denominator in these two years is a strong Kamchatka PV lobe and bering sea/GOA ridging. Unless we see an uptick in the PDO/ENSO domains, or a quick downturn in the QBO by feb a major warming in the DJF period is going to be tough to come by. EP heat flux anoms are already starting off winter well below normal ever since the wave 1 response in late october. Our best shot will probably be a wave 2 warming in Feb if we can keep the EPO ridge consistent which becomes more likely given the +QBO/N ENSO and -EPO persistence. If this doesn't work out then their is always the FW question in March/April that should arise with a mean state similar to our current one. This SSW timing is much more favoured given the current setup and could have impacts on spring, especially with the warming ENSO region expected and a transitioning QBO index(favourable for high heights across the NAO/EPO region's).

 

Feb 2001

BPyCM4uBVr.png

Feb 2009

PvEg8QtxK0.png

A good post and one that I agree with. Any SSW this winter is the long shot call. Another similar year to look at is Feb 1979, neutral ENSO, -ve PDO. There was far less of the Kamchatka vortex and stronger Bering ridging that year. Strong enough for an early FW as well in the Berlin archives (though not according NASA)

 

 

Big wave 2 activity - but it took two attempts to break the vortex one at the end of Jan and the other at the end of Feb that finally succeeded.

 

 

 

It's a pity that we can't see what happened wave wise earlier that winter. Those concentrating on the favourite this winter should just keep an eye on their blind side that the long shot doesn't creep up on them!

[UV-RAY]

A good post and one that I agree with. Any SSW this winter is the long shot call. Another similar year to look at is Feb 1979, neutral ENSO, -ve PDO. There was far less of the Kamchatka vortex and stronger Bering ridging that year. Strong enough for an early FW as well in the Berlin archives (though not according NASA)

 

epV5Vh6eNu.png

 

Big wave 2 activity - but it took two attempts to break the vortex one at the end of Jan and the other at the end of Feb that finally succeeded.

 

Screen Shot 2013-11-30 at 08.00.36.png

 

Screen Shot 2013-11-30 at 08.04.06.png

 

It's a pity that we can't see what happened wave wise earlier that winter. Those concentrating on the favourite this winter should just keep an eye on their blind side that the long shot doesn't creep up on them!

Do we have any data for a SSW for the winter of 1947, that also had a west based QBO?

[Catacol]

There are signs of a slow down in the zonal winds at 50 - 100 hPa at 60N in the output today. 

 

Grog help please - is this due to the impact of sustained minor warming, or is it a sign that the cooling of the strat is beginning to bottom out naturally for the season? Signs of this here, with a juddery rebound?

 

 

 

I do not have the charts to compare... but in previous years where we have reached an early minima in strat temps over the north pole what has this graph tended to look like over the rest of Dec/Jan? Dependent on QBO and all that sort of thing I'm sure - but I still have a beginner's sense that the speed of the cool down and vortex enhancement may be significant. In similar analogue years have we had the same kind of early brush with the -80 mark?

[Cloud 10]

Here is the 2011/2012 30mb plot.

 

 

 

Not surprised i saved that one!

[UV-RAY]

Here is the 2011/2012 30mb plot.

 

pole30_nh.gif

 

 

Not surprised i saved that one!

A prime example of a warming event which did bring about HLB but this wasn't in a more favourable position for cold to back far enough westwards and left many in the western half of the UK on the boundary of cold / mild airmasses.

[Tamara]

If we take the QBO in isolation of other factors, then forecasts suggest that the +QBO will weaken over the winter and that at face value should make stratospheric vortex disturbances more likely to be successful. What is key though is how fast in reality this decay happens.

 

This is especially true on the basis that if we take the very good post by blizzard of 96 into account, the expectations that I have seen agreed in most professional forecasts suggest that both ENSO (fairly neutral) and PDO values (neutral to negative) are expected to retain similar status through the winter to the present time.

 

There is actually something of a conflict going on with a Nina like background to the actual ENSO Pacific signal but the atmosphere is trying to force a more Nino like pattern. How this conflict is resolved will have implications as/when/if it is resolved in terms of prospects for the coldest potential time period of the winter.

 

There is a line of thinking that the base AO state through the winter has a larger effect on what happens to the EPO state through the winter. The base state of the AO becomes more influential on other indices as wavelengths become longer towards the heart of winter - i.e December into January

 

Being highly variable, the EPO ridge can be poleward (as long as the NH AO state is not too highly positive) but it can flatten and turn more positive if the AO state becomes highly positive such that no blocking signature is achievable into the arctic.  So if the upcoming wave 1 activity is weak at the same time as the upper vortex heads towards peak winter time maturity, there is a risk that the -EPO signature could wane and this then has the implications for any wave 2 activity further down the line in the second half of the winter, which we hope for to break down the vortex whilst the days are still short enough to deliver.

 

We can't rely on a March 2013 scenario to occur very often!!

 

We are dependant on all these factors to play out favourably. Taking everything into consideration, the best maybe we can hope for is a split vortex perhaps into February, but it looks like it could be hard work, especially if the wheels fall off the above.

Edited November 30, 2013 by Tamara תָּמָר

[Severe Siberian icy blast]

If we take the QBO in isolation of other factors, then forecasts suggest that the +QBO will weaken over the winter and that at face value should make stratospheric vortex disturbances more likely to be successful. What is key though is how fast in reality this decay happens. This is especially true on the basis that if we take the very good post by blizzard of 96 into account, the expectations that I have seen agreed in most professional forecasts suggest that both ENSO (fairly neutral) and PDO values (neutral to negative) are expected to retain similar status through the winter to the present time. There is actually something of a conflict going on with a Nina like background to the actual ENSO Pacific signal but the atmosphere is trying to force a more Nino like pattern. How this conflict is resolved will have implications as/when/if it is resolved in terms of prospects for the coldest potential time period of the winter. There is a line of thinking that the base AO state through the winter has a larger effect on what happens to the EPO state through the winter. The base state of the AO becomes more influential on other indices as wavelengths become longer towards the heart of winter - i.e December into January Being highly variable, the EPO ridge can be poleward (as long as the NH AO state is not too highly positive) but it can flatten and turn more positive if the AO state becomes highly positive such that no blocking signature is achievable into the arctic.  So if the upcoming wave 1 activity is weak at the same time as the upper vortex heads towards peak winter time maturity, there is a risk that the -EPO signature could wane and this then has the implications for any wave 2 activity further down the line in the second half of the winter, which we hope for to break down the vortex whilst the days are still short enough to deliver. We can't rely on a March 2013 scenario to occur very often!! We are dependant on all these factors to play out favourably. Taking everything into consideration, the best maybe we can hope for is a split vortex perhaps into February, but it looks like it could be hard work, especially if the wheels fall off the above.

So in reality you don't think sustainable cold is achievable between now and feb , which is over 2 months away , that's a very big call to make before December begins , i hope to goodness that's wrong . Your knowledge is amazing and thanks for sharing it with us recently , although the optimism in me makes me pessimistic in regards to you writing off 2/3'rds of winter .

[Winter Monsoon]

Can i just ask, is that 2 vortices?

 

[bluearmy]

Can i just ask, is that 2 vortices?

It is a split at the very bottom of the strat and stretched a bit higher up but this is real fi stuff at T384

[Winter Monsoon]

It is a split at the very bottom of the strat and stretched a bit higher up but this is real fi stuff at T384

 

Its T288 charts but @ 100mb it starts at T228.  And reaches 20mb @ T288. 

[feb1991blizzard]

It is a split at the very bottom of the strat and stretched a bit higher up but this is real fi stuff at T384

 

It was 288hrs but reforms unfortunately anyway by 384 at 20mb. 

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2013113018&var=HGT&lev=20mb&hour=384

[Tamara]

 

So in reality you don't think sustainable cold is achievable between now and feb , which is over 2 months away , that's a very big call to make before December begins , i hope to goodness that's wrong . Your knowledge is amazing and thanks for sharing it with us recently , although the optimism in me makes me pessimistic in regards to you writing off 2/3'rds of winter .

I'm not a girl to willingly write sections of winter off for sure  Its more a case of looking at the possibilities and this winter presents more challenges at face value than last winter. Of course colder interludes are possible throughout the winter and a distinctly average winter is *most likely* overall.

 

We know from last winter that in the UK, as a small Island, we need things to fit in place even during favourable stratospheric winters when cold spells arrived following the SSW in January and a further vortex assault into March that led to that phenomenally cold and blocked month. We should also remember that recent winters like 09/10 and the first part of 10/11 were quite exceptional even by historical comparisons

Edited December 1, 2013 by Tamara תָּמָר