Stratosphere Temperature Watch 2014/2015

[MattH]

Just posting these images, sort of as a one off but whilst the 12Z HRES, as it is properly called that we all see, is quite an extreme solution, as you can see from the MLSP and 500hpa heights there is some consistency for that ridge to build over Greenland which has implications with regards to wave breaking and particularly wave 2 activity...

 

I can't post the EC Clusters and postate stamps for a number of reasons, but what I can say is that out of the 51 EC ENS members there is an approx 38 members which allow the ridge to the NE to build towards Greenland to create more of a block and allow the E or NE'ly flow. Coming back to the strat and again what is important here is having the block over Greenland which will then allow for wave breaking to take place from upwelling and at the moment, going off the 12Z EC ENS from what I can see the odds on are that the 12Z HRES model isn't far from the truth. Whether this signal will continue as clearly consistency is now key is anyones guess, but 'we' could be on to something here.

 

Sort of making a forecast I would imagine, given everything I've seen of the 12Z ECM that when the Berlin charts become available later today and overnight the signal for Wave 2 activity will have continued to increase in amplitude and that the split from the bottom up remains present, but we shall see.

 

Regards, Matt.

[MattH]

Just a quick one and I'll keep it brief, but yesterday's 12Z ECM from the Berlin site is not a step in the right direction. In a way comparing and contrasting each run is not what this thread is about really, so again I'll keep it brief, but compared with charts from the 12Z 7th run, when wave 2 looked to be on the increase and a split was evident from the bottom up, that signal has been reduced on yesterday's (8th 12Z) models. The split isn't really there and importantly the ridge over Greenland isn't there either and whilst wave 1 increases at the top of the strat, wave 2 is insignificant. Following link/images highlight this...

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=ha2&lng=eng

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=70&forecast=all&lng=eng#fig11

 

Oooddles of time left and the vortex remains in a disorganised state and especially with regards to its influences on the troposphere, but it's a waiting game, simple as that.

 

Matt.

Edited November 9, 2014 by MattHugo

[Frozen Britain]

Warming even stronger at the top of the stratosphere again today after being strong earlier this week before waning again. Today, it is even stronger than it was the last time I posted it looks like. It's a shame we are not seeing this lower down the stratosphere where we want to see it to enable the vortex to split. Still, it is good to see that the lower stratosphere is not undergoing rapid cooling. The profile has not changed much at all, if at all, during October, and it looks like that will continue this month too. Fingers crossed. Sorry to keep posting these up. I am just keeping the interest and excitement alive.

Edited November 9, 2014 by reef

[snowking]

Just reading through Cohen's blog, and had to pull out a few tidbits of interest.

 

The first one is this:

 

 

 

Although sudden stratospheric warmings are more typical in early-mid winter, the setup as of now favors an earlier warming event, possibly in late November / early December. Although the AO will be in a negative state in week 2, it will likely transition to neutral or even positive as the stratospheric warming event gets underway.

 

Of course we are starting to see this appear now in both the ECMWF and GFS suites, and it also confirms recent discussions regarding the unusually early nature of the repercussions from a high SAI. Whilst a few days out of date, the below chart from the blog also looks pretty useful:

 

 

In short it shows vertical propagation of wave flux - and as you can hopefully see, there appears to be particularly strong propagation through much of the stratosphere forecast through the next couple of weeks.

 

I am anticipating a barrage of 'winters over' posts over in the MOD thread if we do indeed transition back towards a neutral/positive AO state towards the end of the month, but I am hoping the sensible posts from some of the more seasoned members are helping to temper expectations a little. The truth is following a high SAI, early winter is not a favourable time for Western European cold - there is always a slim chance that this occurs consequentially given the strengthening Siberian high, but generally speaking I hold more interest in seeing the cold air pool to our East as opposed to watching and expecting it to be advected our way early on.

 

But it should be noted once again that we do seem, at the moment at least, to be working on an accelerated timeline. My personal expectations following the SAI/OPI final figures had been that we would not see anything too significant cold wise until January. But given where we find ourselves right now, I cannot disagree too much with the below:

 

 

 

Given the predicted already weakened state of the stratospheric polar vortex, we are monitoring closely a possible early weakening of the stratospheric polar vortex. The response in the troposphere following the stratospheric warming event is a more negative AO state, which is typically experienced about a week after the warming event and can persist for several weeks thereafter. This should promote colder temperatures across northern Eurasia and probably the Central and Southeastern US by mid-December.

 

So what am I personally looking for with the upcoming -AO period? Simply to start building a cold pool to our East, ready for us hopefully to 'tap into' a little further down the line.

 

At this stage the only factor I can see counter to the theory of a -AO this winter is the average to slightly above average sea ice extent around Barents/Kara, as Cohen mentions too, but on the grand scale of things and given that this is a very recent theory with little conclusive supporting evidence for the moment it does not concern me greatly.

 

Even if we do not hit the holy grail here in the UK, stratospherically this is going to be another fascinating season and thankfully should provide a stark contrast to last 'winter'

 

SK

[Hocus Pocus]

Excellent post SK and simply put in laymens terms, which for someone like me is much appreciated. I'm with you on looking at the bigger picture further down the line hopefully seeing that block to our East link up with a Greenland high mid winter onwards. The fact that we've got something to pin our hopes on makes this coming winter far more enjoyable to watch ( from a cold perspective ) than last years PV fest. Does Cohens work also have any correlation with those strong height anomolies we've seen over the NE Pacific over the last year or so?

[MattH]

Brilliant post SK...

 

Get that posted over in the Model Output thread as well. Long gone have the days of me getting involved with model output threads and forums, the strat thread is uniquely different, but I can imagine there'll be plenty of WIO (Winter Is Over!) posts there, but it's posts and information like that, in this thread, which make it the best on the net.

 

Cheers, Matt.

[SMU]

Just reading through Cohen's blog, and had to pull out a few tidbits of interest.

 

The first one is this:

 

 

Of course we are starting to see this appear now in both the ECMWF and GFS suites, and it also confirms recent discussions regarding the unusually early nature of the repercussions from a high SAI. Whilst a few days out of date, the below chart from the blog also looks pretty useful:

 

 

 

In short it shows vertical propagation of wave flux - and as you can hopefully see, there appears to be particularly strong propagation through much of the stratosphere forecast through the next couple of weeks.

 

I am anticipating a barrage of 'winters over' posts over in the MOD thread if we do indeed transition back towards a neutral/positive AO state towards the end of the month, but I am hoping the sensible posts from some of the more seasoned members are helping to temper expectations a little. The truth is following a high SAI, early winter is not a favourable time for Western European cold - there is always a slim chance that this occurs consequentially given the strengthening Siberian high, but generally speaking I hold more interest in seeing the cold air pool to our East as opposed to watching and expecting it to be advected our way early on.

 

But it should be noted once again that we do seem, at the moment at least, to be working on an accelerated timeline. My personal expectations following the SAI/OPI final figures had been that we would not see anything too significant cold wise until January. But given where we find ourselves right now, I cannot disagree too much with the below:

 

 

So what am I personally looking for with the upcoming -AO period? Simply to start building a cold pool to our East, ready for us hopefully to 'tap into' a little further down the line.

 

At this stage the only factor I can see counter to the theory of a -AO this winter is the average to slightly above average sea ice extent around Barents/Kara, as Cohen mentions too, but on the grand scale of things and given that this is a very recent theory with little conclusive supporting evidence for the moment it does not concern me greatly.

 

Even if we do not hit the holy grail here in the UK, stratospherically this is going to be another fascinating season and thankfully should provide a stark contrast to last 'winter'

 

SK

 

Hi SK

 

I rarely venture in here-  I cant post in all threads-  A nice round up.

 

Interesting about the comment for cold in certain locale-  the current ECM wave 2 wave breaking event will certainly change the dynamics of where the cold sets up though-

 

UKMO & GFS WAVES indicate what Cohen says-

 

GFS

 

ECM

 

As we can see both are -AO negative, however the alignment of the wave breaking is different with the ECM a complete vortex split & cold flooding West from Eurasia, the GFS has the cold cross polar feeding the American pattern.

 

Only one configuration is cold for the UK.....

 

S

 

[stewfox]

 

Imagine having a circular bath with a plug in the middle. Once this plug is pulled out the water will flow out in a circular motion with the plug hole being the centre of the vortex. If I was then to insert a brick into the bath towards the edge of the vortex then the flow would be disrupted significantly and diverted around the brick - we would have created a situation where a wave is created around the flow. If we were then to insert another brick in the bath then we would create two waves disrupting the flow. The first scenario we call a wave number 1 and the second a wave number 2. The size and position of the brick(s) would significantly detemine how the vortex would flow. And so we can consider the same with the stratospheric/tropospheric vortices. 

 

 

 

For those that just love reading these posts , the size of the brick I assume determines how far the water has to go around to get back to the plug hole. Small disruptions pebbles etc happy frequently and would push the vortex 5 degrees further south but bigger wave disruptions ie a bigger bricks could push the colder air much further south ??

 

Would two wave disruptions interact or would they like the brick analogy not if they were on opposite sides of the plug hole. ie the water would only go around one brick and drop back into the plug hole and wouldn't be affected by the other brick ? However as you have posted we could be getting the vortex disrupted on both sides of the globe with more of a chance of us in the UK getting some of that diverted cold water with two large bricks (2 waves disruptions) at the same time ? 

[SMU]

Hi stew

2 bricks as a symetrical positions increase the disruption to the flow creating more eddies-

The ECM today has 2 bricks plus a bag of cement over the plug hole.....

[shaky]

Hi stew

2 bricks as a symetrical positions increase the disruption to the flow creating more eddies-

The ECM today has 2 bricks plus a bag of cement over the plug hole.....

steve what signs are you looking for early on in the 12z runs when they come out?do you think they will revert back to what they were showing yesterday with a nice greenland high!!

[Interitus]

Just reading through Cohen's blog, and had to pull out a few tidbits of interest.

 

 

That's worth linking to - https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

The one thing about the whole SAI stuff is that while the papers are compelling, it is not easy to determine the effect in actual archive charts, certainly not as an overwhelming and dominant feature at any rate. The Japan Met Agency has a good series of archives including 300mb Wave Activity Flux at variable time periods from 5 days to 3 months - http://ds.data.jma.go.jp/tcc/tcc/products/clisys/acmi.html

To be fair, these don't show WAF anomaly as used by Cohen.

[SMU]

steve what signs are you looking for early on in the 12z runs when they come out?do you think they will revert back to what they were showing yesterday with a nice greenland high!!

Hi I will looking at 2 areas on the models

* Atlantic on the T 168 timeframe to see whether there is more amplitude in the jet forcing systems up the western side of greenland

* Pole at 192 to see whether the GFS persists with the cross polar low height anomaly or whether it builds heights across the pole like the wave2 scenario painted by ECM -

S

[karyo]

The 12z gfs keeps the vortex in one piece throughout the run and the warming is not as significant as previous runs. Let's hope it is not a trend.

 

Karyo

[shaky]

The 12z gfs keeps the vortex in one piece throughout the run and the warming is not as significant as previous runs. Let's hope it is not a trend.

 

Karyo

you mean the parallel run cos the normal 12z run was a close to a dream run for coldies!

[bluearmy]

you mean the parallel run cos the normal 12z run was a close to a dream run for coldies!

 

he's referring to the strat vortex shaky, not the trop one.

[Duane S.]

Wave2 activity starting to perk up?

 

[Recretos]

The Canadian Warming thing still remains for me one of these long overdue mysteries. Am still not comfortable with my understanding of how they are classed among other displacement, split events, or even 'when' they get labelled a Canadian warming versus a displacement. Still from the archive found this analog of November CW years based on the Berlin data table, which looks like we are heading to Canada this November.

 

November Canadian Warming Analog Years.pngnaefsnh-0-0-216.png

naefsnh-0-0-216.pngEDH101-240.GIF

 

Good further tweet action Matt on the GWO and caveats for use of the site linked earlier beyond day 7 re: ensemble smoothing.

 

These charts from Lorenzo remind me of SAI at work in practice, as was noted when I was doing the plots for correlations. 

 

Instead of posting only model outputs, I decided to do something else. I have plotted linear correlation between November N. Hemisphere snowcover area and geopotential height in mid and lower strat. This isnt really any new info, but just it is interesting and it kinda supports the SAI theory. 

 

I am not going to go into the theory of linear correlations, unless a lot of people wouldn't know what its about. 

 

The correlation at 100mb is pretty straightforward, with the wave2-ish look to it, with the difference that instead of the usual Atl-Pac waves, we have more of a Eur/As-Pac combination. 

 

 

In the mid strat, the correlation is there for decent wave activity, with more of a wave2 feel to it, but at least a strong wave 1. 

 

 

And the 500mb correlation, which is not that far from the reality this month. 

 

  

 

Ok, back to now. I am going to post some parallels again. Keeps the spirit alive and the upper strat vortex in a pretty bad shape, I have to say. 

 

 

 

 

 

 

 

And a reminder on the beast of last year:

 

 

And finishing off with the full zonal wind mean, for comparison with ECMWF. 

 

 

I really wish I would have more time for the stratosphere, but I just cant seem to find it at the moment. 

 

Regards.

[MattH]

A case of 'steady away' this morning given latest guidance. Obviously what is going on down in the troposphere may well have an impact on the strat, especially if we can get this blocking high to the N and NW of the UK over Greenland, but as Ed mentioned numerous days ago, it's a waiting game. The significant SAI index this year and given Cohens work, which SK summarised brilliantly this past weekend, may well mean we have to put up some 'close but no cigar' scenarios before we get anything of worth. In a way my thoughts haven't changed and I don't think we'll see anything of worth until December. However, given the state of the strat and how things are developing then Cohens SAI timeline may well need bringing forward as January and February, whilst potentially very interesting months, may well be the icing on the cake, after we've had a good taste of 'said cake' in December, if you know what I mean...

 

Few charts of interest this morning...

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f240.gif

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha1_f216.gif

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta1_f240.gif

 

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

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf50f240.gif

 

https://max.nwstatic.co.uk/gfsimages/gfs.20141110/00/348/npst30.png

 

Again, steady away really, nothing too significant, but the signals are not going the other way either. A case of remembering 2009 and 2010 in terms of having to put up with some wet and windy weather before things develop with time, clearly these years quite an extreme example, but I have a feeling it could well be similar this year, the 'Winter Is Over' posts may well become ever frequent by late November, but with then a quick and interesting change in conditions as December progresses.

 

Regards, Matt.

[lorenzo]

Vorticity123 has started a great new thread in the Learning area for interpretation of the Berlin charts, hopefully over time this can then be made into a guide and assist those wanting to join in the day to day stratosphere model output discussion. Any and all contributions welcome.

 

https://forum.netweather.tv/topic/81786-interpreting-stratospheric-temperature-flux-charts/

 

 

[Nouska]

I haven't seen anyone link to the NOAA FIM model - they have nice animations, out to +336, of the stratosphere and include flux and ozone mixing options.

 

Menu for NH is new Arctic option.

 

http://fim.noaa.gov/FIM/Welcome.cgi?dsKey=fim_jet&domain=201&run_time=10+Nov+2014+-+00Z

[tcc]

A case of 'steady away' this morning given latest guidance. Obviously what is going on down in the troposphere may well have an impact on the strat, especially if we can get this blocking high to the N and NW of the UK over Greenland, but as Ed mentioned numerous days ago, it's a waiting game. The significant SAI index this year and given Cohens work, which SK summarised brilliantly this past weekend, may well mean we have to put up some 'close but no cigar' scenarios before we get anything of worth. In a way my thoughts haven't changed and I don't think we'll see anything of worth until December. However, given the state of the strat and how things are developing then Cohens SAI timeline may well need bringing forward as January and February, whilst potentially very interesting months, may well be the icing on the cake, after we've had a good taste of 'said cake' in December, if you know what I mean...

 

Few charts of interest this morning...

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f240.gif

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha1_f216.gif

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta1_f240.gif

 

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

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf50f240.gif

 

https://max.nwstatic.co.uk/gfsimages/gfs.20141110/00/348/npst30.png

 

Again, steady away really, nothing too significant, but the signals are not going the other way either. A case of remembering 2009 and 2010 in terms of having to put up with some wet and windy weather before things develop with time, clearly these years quite an extreme example, but I have a feeling it could well be similar this year, the 'Winter Is Over' posts may well become ever frequent by late November, but with then a quick and interesting change in conditions as December progresses.

 

Regards, Matt.

Just wanted to say Matt I look forward to your summaries each morning! We have Gibby doing his on the Mod thread and you doing them here for the Strat. Brilliant! Keep it up

[Tyfelin]

Folks - just wanted to say hi. I found this thread fascinating last year, but failed to contribute. Hope to put that right this season. I'm intrigued by the sheer scale of the processes wrestled with here, as well as potentially the ability to get some insights into what winter has in store for us. I note we're off to a cracking start, with the Met Office seemingly standing firmly behind its 'warm, wet and windy' prediction, in some contrast to views expressed here.

tyfelin

[lorenzo]

Welcome along to NetWx Tyfelin.

 

WSI just posted up a very healthy looking ECM mean which speaks for itself wrt Wave 1 activity, would be nice to see 30mb too..

 

 

 

[Nouska]

Welcome along to NetWx Tyfelin.

 

WSI just posted up a very healthy looking ECM mean which speaks for itself wrt Wave 1 activity, would be nice to see 30mb too..

 

WSI.PNGB2FWNc3IYAAUtu_.png

 

Thank you, Lorenzo. Here's the blog that goes with the tweet.

 

http://www.wsi.com/blog/energy/it-might-be-time-to-start-monitoring-the-stratosphere/

[lorenzo]

Thanks, a nice write up from Mike, they are at real odds over there at the moment where in some quarters any cold outbreak is tagged up as the 'Polar Vortex' due to the frenzy of last year. Hopefully this blog will go some way to correct this. Also importantly distinguishes that this is not SSW, rather Wave 1 displacement event. We have seen hints of split during October and in outer reaches of FI however not quite there yet.

 

I think AER may have tweeted that this is the most significant SAI since monitoring of index created in 97,  if not Top 3 as per Mike's in house guide then could even smash in at number one on the index. The odds are this delivers at least one month of highly negative AO within a mean negative DJF.

 

For the years in question -

 

 

This year

 

Also here are the Wave 1 and 2 for the preceding OND to go along with the years featured in the blog- gives you a great idea of how exceptional 2009 was and links to the SSW's the following January.

 

 

http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2010_01_30.gif

 

http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2013_01_17.gif