Stratosphere Temperature Watch 2015/2016

[phil nw.]

We can see that there has been warming at the top and the reduction in zonal winds up there

but lower down seems there's little change expected yet.Still quite cold at 30hPa although there are signs of vortex stretching in the next 2 weeks.

no sign yet of any displacement but certainly it's being stretched almost like an elastic band waiting to snap(split?).

 

[Singularity]

What's striking to me is the consistency with which GFS keeps producing areas of high pressure right beneath that displaced/stretched vortex. Fits with the idea of changes attempting to work their way up from the trop. instead of down from the high stratosphere. If anything there's changes being signalled at both ends but not so much in the middle.

This leads me to ask; what are the odds of an event of such nature as Nov-Dec 2010 which I believe was trop-driven? TIA.

[Recretos]

2 hours ago, BrickFielder said:

The royal Society publishing document on the relationship between stratospheric structure and tropospheric blocking patterns is interesting. I would agree that it makes sense that tropospheric conditions would affect the lower stratosphere. Where conditions in both the stratosphere and troposphere are acting to raise or lower the tropopause then they are likely to affect each other. What I think is not really explained well in the report is the concept of decoupling between the stratosphere and the troposphere and the importance of the scale of disturbances. Lets look at two current charts. Firstly the 380K Potential Vorticity Chart which I think has some correlation to tropospheric conditions (Not exactly but could be used for an element of prediction). Here I assume (always dangerous) that tropospheric influence on the stratosphere has been taken into account in the modelling.

Secondly the 475K Potentail Vorticity Chart which correlates much better with the upper stratospheric vortex conditions rather than the lower stratosphere or troposphere.

 

 

Yet again, when dealing with the IPV fields, I do hope you are taking the relative height of these fields into consideration.  380K is around the 100mb level, and 475K is around the 60mb level. So b oth fields are bordering both the trop and strat, with the 475K being actually in the lower stratosphere. 

Edited December 30, 2015 by Recretos

[fromey]

Hi guys, I have never posted in here before and I'm very much a novice so be gentle!!

a very quick set of questions, how will the rise in temperature in the artic affect the vortex etc, do the models have the data set to calculate such things and how will this pan out on the GFS,ECM and uk met models??

 

many thanks

 

fromey

[fergieweather]

On 12/30/2015 at 11:34 AM, feb1991blizzard said:

I wonder if Ian would be kind enough to let us know as and when anything significant happens towards early Feb on the GLOSEA5 please?

Sorry for late response. In short, latest GloSea5 strat diagnostics (they run each day) are indicative of any SSW more likely occuring during Feb. This remains consistent with previous probabilistic outlining of 3-month expectations in contingency planning updates prepared by UKMO's Seasonal Team; i.e., higher likelihood of any colder weather being at tail-end of this winter and perhaps thus extending on into March. Of course, it must be re-stressed that the potential for any colder phases occurring during the rest of this winter won't necessarily be reliant on a SSW alone. There's presently no compelling signal in GloSea for any marked cold weather during the rest of January (it leans slightly milder than avg overall with a generally straight/zonal pattern throughout...this versus EC Monthly's slight NW'ly bias and more typical/avg temperatures). However, we will see what this evening's EC Monthly update yields (as it should now reduce any previous assimilation lag issues that might have snuck-in, whilst synthesising Frank's impressive poleward bout of WAA).

[Hocus Pocus]

Sober reading Ian and up to now the GLOSEA5 has been rock steady in its outlook since Autumn so I'll be inclined to go along with that for the forseeable, or until it picks up a new signal.

[chionomaniac]

15 hours ago, fromey said:

Hi guys, I have never posted in here before and I'm very much a novice so be gentle!!

a very quick set of questions, how will the rise in temperature in the artic affect the vortex etc, do the models have the data set to calculate such things and how will this pan out on the GFS,ECM and uk met models??

 

many thanks

 

fromey

The rise in Arctic temperatures seen through Warm Air Advection (or often shortened on here to WAA) is mainly a troposphere based event. And it is having a strong affect on the tropospheric polar vortex with a strong drop in the AO affecting the Arctic region and the vortex segmented displace away from the pole. see below where the strong Kara Sea block resides

 

 

 

This pattern does affect the stratosphere - but only the lower reaches(100hPA) towards the upper strat 10hPA there is no noticeable trop affect - but trop wave feedback may occur later

 

Eventually the redistribution of polar blocking may create a trop based split in the lower strat and this may stretch further up the strat - but this is very much trop upward wave activity in the centre of the vortex. An SSW is associated with heating from straong wave activity propagating down from the upper strat

 

 

Will edit to add charts as function isn't working presently on my computer!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited December 31, 2015 by chionomaniac

[BrickFielder]

20 hours ago, Recretos said:

 

Yet again, when dealing with the IPV fields, I do hope you are taking the relative height of these fields into consideration.  380K is around the 100mb level, and 475K is around the 60mb level. So both fields are bordering both the trop and strat, with the 475K being actually in the lower stratosphere. 

Yes isentropic level380K is close to the 100 hPa isobaric surface which is generally just above the tropopause (150hpa tropics down to 400hpa further north) and isentropic 475K  level is close to the 60hpa level. So yes 380K very close to the boundary  of the Stratosphere and Troposphere and  475K is a little above that.

In looking at these charts I am thinking about synoptic eddy feedback as a mechanism for lower stratosphere potential vorticity to have impacts on the troposphere.

Discussion on the role of synoptic eddies in the tropospheric response to stratospheric variability. http://www.cgd.ucar.edu/staff/lantao/publications/2013_DSC_GRL.pdf

Paper which discusses stratospheric vortexes and the different ideas about how the stratosphere influences the troposphere including PV inversion, changes in refractive properties / Rossby wave propagation and  synoptic eddy feedback.

http://www.columbia.edu/~lmp/paps/waugh%2Bpolvani-PlumbFestVolume-2010.pdf
 

[feb1991blizzard]

2 hours ago, fergieweather said:

Sorry for late response. In short, latest GloSea5 strat diagnostics (they run each day) are indicative of any SSW more likely occuring during Feb. This remains consistent with previous probabilistic outlining of 3-month expectations in contingency planning updates prepared by UKMO's Seasonal Team; i.e., higher likelihood of any colder weather being at tail-end of this winter and perhaps thus extending on into March. Of course, it must be re-stressed that the potential for any colder phases occurring during the rest of this winter won't necessarily be reliant on a SSW alone. There's presently no compelling signal in GloSea for any marked cold weather during the rest of January (it leans slightly milder than avg overall with a generally straight/zonal pattern throughout...this versus EC Monthly's slight NW'ly bias and more typical/avg temperatures). However, we will see what this evening's EC Monthly update yields (as it should now reduce any previous assimilation lag issues that might have snuck-in, whilst synthesising Frank's impressive poleward bout of WAA).

Thank you so much Ian, Pretty much what I thought to be honest.

[Faronstream]

Is there any chance of a major Stratosperic warming the upcoming 2 weeks, which can lead to HT blockage over Barents sea with extremly cold northerly winds over most of Scandinavia ( and eventually GB later) ?

I ask this since i have a hard time understanding the 10hpa temperature maps, vortex split effects and so on

[karyo]

10 minutes ago, Faronstream said:

Is there any chance of a major Stratosperic warming the upcoming 2 weeks, which can lead to HT blockage over Barents sea with extremly cold northerly winds over most of Scandinavia ( and eventually GB later) ?

I ask this since i have a hard time understanding the 10hpa temperature maps, vortex split effects and so on

Unfortunately, there isn't.

[Singularity]

There may not be a SSW but the vortex sure looks a bit mangled at 10 hpa by the end of the 12z GFS det. based on the temps.

The 18z has the vortex putting up more of a fight until mid-FI, only to weaken at a considerable pace from there to run's end:

Edited January 1, 2016 by Singularity

[chionomaniac]

3 minutes ago, Singularity said:

There may not be a SSW but the vortex sure looks a bit mangled at 10 hpa by the end of the 12z GFS det. based on the temps.

The 18z has the vortex putting up more of a fight until mid-FI, only to weaken at a considerable pace from there to run's end:

 

It's another one of those times when the vortex is in distress but we just need the right wave activity to bring it down. We have suffered with timing issues in the last few years and yet again we have another year where the vortex is ripe for further destruction and that may still come.

[Singularity]

10 hours ago, chionomaniac said:

It's another one of those times when the vortex is in distress but we just need the right wave activity to bring it down. We have suffered with timing issues in the last few years and yet again we have another year where the vortex is ripe for further destruction and that may still come.

Here's hoping Chiono.

Hoping that loss of MJO amplification 30th-31st is just a blip as it seems that the stronger it is, the more dramatic the feedbacks are likely to be down the line. If I'm right?

Serious differences between how GEFS and ECMF handle the speed of the MJO over the coming week based on yesterday's runs. I've seen IDO posting in favour of the ECMF on the MOD thread, yet I've been tracking the MJO plot sand while GEFS has been erroneous, ECMF has been just as far away on just as many days, going by eye. 

ECMF's hyper-speed projection does at least show us that return to the Indian Ocean that GP has factored into his recent thoughts. With the right timing we could get away with it... or even use it to our favour if I'm interpreting his words correctly.

 

With so much active weather coming our way in the meantime, I don't expect to have as much time as I'd like for looking at the colder possibilities late month. Then again, given the wait required, that might be for the best!

Still signs that tropospheric vortex perturbation may be sufficient to bring about a transient northerly mid-month as HLB shuffles about. Not enough for the Met Office to drop a hint yet, though.

[Azores Hi]

Back in the dawn of time of strat discussion we referred mainly to this chart and OMG I don't remember anything this bad! This is your cue ( more modern experts) to say this is just one dimension and tell me why we still have hope for this winter? 

[Rocheydub]

I'll hazard and say that a vortex destruction (hopefully) this season will be trop lead, and not a strat warming. While it's trending downward (no argument here), it doesn't rule out a strat warming or even a SSW.

[Cloud 10]

12 hours ago, Azores Hi said:

Back in the dawn of time of strat discussion we referred mainly to this chart and OMG I don't remember anything this bad! This is your cue ( more modern experts) to say this is just one dimension and tell me why we still have hope for this winter? 

 

Was nearly as low as that a few years ago,but then look what happened!

 

 

Sadly nothing like that scale of warming being projected for this winter........yet.

[karyo]

3 hours ago, Cloud 10 said:

 

Was nearly as low as that a few years ago,but then look what happened!

 

 

Sadly nothing like that scale of warming being projected for this winter........yet.

The temperatures were already on the up at this stage though while currently they are still going down.

As you say no significant warming is in the forecast for the next two weeks.

[Mokidugway]

Past performance is no indicator of future returns ......

[Catacol]

But on the upside perhaps the latter half of this winter will show that stratospheric influence is not the only factor that explains or precipitates cold. The interaction between tropical convection and the strong El Nino is looking like the key driver of any change this time around.... and tropospheric impacts on the strat may end up far more inportant than the top down impacts we have come to expect to be key.

[damianslaw]

What is the average date in a winter for the strat to hit its coldest point? Given we started the winter with the strat at a very cold level already - shouldn't we at least be seeing a plateau now??

 

I'm sure those in know can point to cold periods coinciding with no SSW and therefore a cold strat.

Edited January 3, 2016 by damianslaw

[MJO]

hi- so Kara Sea block makes the a AO go negaive ?!

[damianslaw]

Always a good read Cohen Blog - despite suggestion of no SSW, the last chart is encouraging for those wanting colder weather. A lot of blue over northern Europe, UK and over France.

[BrickFielder]

Hints of a northerly regime developing next week.

[karyo]

A pretty impressive stratospheric warming on the 12z gfs starting just after 300hours. Sorry can't post image.

It is the first run that shows this so to be taken with caution and I am sure most people are focusing on the tropospheric output to notice it.

Karyo