Stratosphere Temperature Watch 2013/2014

[feb1991blizzard]

^^

 

 

I stand to be corrected but as i understand it an SSW is actually defined by the reversal of zonal mean winds from Westerlies to Easterlies at 60N and 10hpa, rather than the actual temperatures, although a sudden rise in temps is what causes it. so you cant tell by that chart as that is only at 2mb and only shows temps.

 

 

This is the best chart to demonstrate this point.

 

On this chart RED = Westerliies and blue = Easterlies, the number down the left is the level of atmosphere and along the bottom shows the latitude, so where the 60 degree line and 10hpa line meet its shows red, if it showed blue that would be an SSW.

 

 

 

EDIT  : While your online, thanks very much Recretos for plotting the GEFS mean 10mb temp charts, i know they are your own plots but just wondering what site you actually get the data from, so i can look it up myself in future?

-

Edited January 16, 2014 by feb1991blizzard

[Recretos]

First I have to apologise for not plotting the MJO composites, because I had some other priorities. 

 

To answer blizzard:

I get data from the NCEP FTP servers.  http://www.ftp.ncep.noaa.gov/data/nccf/com/

 

Regards.

[feb1991blizzard]

First I have to apologise for not plotting the MJO composites, because I had some other priorities. 

 

To answer blizzard:

I get data from the NCEP FTP servers.  http://www.ftp.ncep.noaa.gov/data/nccf/com/

 

Regards.

 

 

Cheers, looks like i cant open them, my computer is naff but will have another go tomorrow, thanks though.

[aginob]

hi to all

 

for user recretos

your NOAA NCEP ftp server link

http://www.ftp.ncep..../data/nccf/com

no can open files and no can see ( why ? )

special software ?

thanks !

Edited January 16, 2014 by aginob

[forecaster]

To open GRIB files (meteorological standard for model data) you can use: http://www.unidata.ucar.edu/software/idv/

[snowking]

Hmmm not great with this,but on twit, Claims that SSW has started.? Er chio.

 

 

Not quite, there has certainly been a warming but we are yet to see the reversal of the zonal winds up in the stratosphere from the more recent warming (to this extent the term 'warming' within SSW can almost be misleading in terms of the definition as it is generally the increase of temperature which causes the winds to reverse direction but it needs the winds to reverse to achieve a technical SSW)

 

Although anyone following this subject on Twitter could understandably get confused.

 

The trouble is this is an extremely complicated and relatively new area of meteorology. We are blessed here in that Ed, and of course previously Stewart had a heck of a lot of time and a wealth of knowledge to offer us to show us the ropes. But over on twitter you will find that even some of the meteorologically trained are still yet to get to grips with the stratosphere. Fortunately we do have some of the more knowledgeable amongst us, notably Lorenzo and Chio posting occasionally on there, and Matt Hugo has been quick to step in and correct any mistakes made there too. It perhaps also doesn't help that Piers Corbyn has decided to create his own definition of what an SSW is to suit his forecasting technique.

 

However, for anyone new to this subject or indeed anyone who has been looking at it for a while now and is still scratching their heads about it all, you should find some comfort in the fact that people who forecast weather for a living (in some cases even teach it to others) are still struggling to get their heads around this vast new empire of knowledge and this brings home just how complex the science involved here is.

 

I think it's fair to say that even the more expertised in this subject continue to learn something new every season and will continue to do so for very many more seasons to come.

 

Regards

SK

Edited January 16, 2014 by snowking

[sebastiaan1973]

There is a lot focus for a SSW, but a substantial reduced zonal wind would do the same trick? E.g. if 60N, 10hPa, the zonal wind will achieve 5m/s, seems to mee a little difference with -1m/s at 60N, 10hPa.

[mcweather]

is that a split vortex we are looking at on the 06z GFS at 384hrs?

 

Edited January 16, 2014 by mcweather

[Ruben Amsterdam]

is that a split vortex we are looking at on the 06z GFS at 384hrs?

 

 

 

A very shortlived split (ish) signature at 100hPa just before this trop chart. At these levels the stratosphere is severly influenced by the troposphere and in my view it's way too early to search for splits at the >100hPa level. The tropospheric (especially in lower levels) output varies wildy from run to run after the Asian warming currently peaking at ~300hrs. Will we see the Asian warming ramp up, or do we switch to a wave-2 pattern? Too early to tell and frankly, I am waiting for the Asian warming to show up in the Berlin graphs before making any calls on the lower strat. Btw: upper strat temperatures significantly lower this morning when compared to the previous GFS runs. 

 

Edited January 16, 2014 by Ruben Amsterdam

[mcweather]

A very shortlived split (ish) signature at 100hPa just before this trop chart. At these levels the stratosphere is severly influenced by the troposphere and in my view it's way too early to search for splits at the >100hPa level. The tropospheric (especially in lower levels) output varies wildy from run to run after the Asian warming currently peaking at ~300hrs. Will we see the Asian warming ramp up, or do we switch to a wave-2 pattern? Too early to tell and frankly, I am waiting for the Asian warming to show up in the Berlin graphs before making any calls on the lower strat. Btw: upper strat temperatures significantly lower this morning when compared to the previous GFS runs. 

 

 

Thanks Ruben.

[snowking]

So the warming we have been tracking for some time now centred around January 28th maintains its consistency and continues to move slowly forward in the output, the 'epicentre' as it were down to +288:

 

 

The next signal that then appears to be emerging is for a warming close to or over the Atlantic sector - still an emerging trend for now but if we take a look at the end of the last few runs:

 

 

We could do with some more consistency within this but nevertheless a bit of a (dare I say it) trend developing to create another minor warming in to early February. Ordinarily such a warming on it's own would not be enough to have an impact but following on from the potential sucker-punch of the January 28th warming (we should bear in mind at this stage it is still an FI forecast) it could prove enough to give the vortex the final kick out of the way/weakening that we need to set up interest in February.

 

The only words of caution I will throw in at this stage (something I commented on last week too) is that with Wave 1 displacements it can be a bit of a lottery. What we are hoping for is that the vortex becomes displaced towards the Siberian/Scandinavian sector as the Wave 1 takes effect. But it would be foolish not to point out the risk of any potential Wave 1 displacement simply pushing the cyclogenesis associated with the upper vortex in to the Atlantic and leaving us in need of a minor miracle (secondary minor warmings could potentially provide such a service). At this stage that all remains conjecture as nobody can tell the exact longwave setup across the Northern Hemisphere for early February this far in advance, but it is a risk that we should be prepared for.

 

Of course the dream scenario in such an event is true cold zonality, but thats a scenario best left alone for now.

 

So positive signs still as we head for February and should current mid-range projections prove true our patience could be rewarded.

 

SK

[Recretos]

 

There is a lot focus for a SSW, but a substantial reduced zonal wind would do the same trick? E.g. if 60N, 10hPa, the zonal wind will achieve 5m/s, seems to mee a little difference with -1m/s at 60N, 10hPa.

 

 

Well, +5 or -1 could also be a difference of 1500m geopotential height in the core, or vortex core being 2000-3000km more to the south, which means the "anti-vortex" (the high ) being more over the pole, etc,... It might not sound like 6 m/s is a big deal, but it can be, in the big picture. Lets just keep to the 60N 10mb zonal wind reversal as a requirement.  Every m/s less helps, once under 10m/s zonal mean.

 

While I am at zonal means, I think that it is almost my duty to make a reality check. The trend seems fairly firm by now. The warming will not keep increasing at 384h. It gets closer and then diminishes. So there is nothing wrong with the models by making the 384h forecasts "colder" than in the last few days. That is just simply the evolution of the current trend. And basically what that means, is that we would need another warming trend. Tho there is still plenty of time for that to develop. 

 

GEFS for example, which has had a ridiculously good consistency, kinda sums it up, but of course on a relatively stronger-than-actual level, since it is an ensemble mean. We will have this first warming, dealing a good blow, but the vortex recovers, just to be hit by the second stronger warming, which also doesn't seem to do the trick. Control looks a bit better, but it still isn't enough. Even GFS is not that convincing. 

 

   

 

The cross-section is not really encouraging either. And the ECMWF is now starting to grab onto the vortex recovery phase I mentioned above.

 

 

 

I don't want to be seen as a pessimist, but I am trying to put a bit more emphasis on the zonal wind aspect, since it is just as important as the warming. And the zonal wind forecasts are not really close to a technical SSW, so I wont even start speculating about possible effect of this warming on the troposphere. Lets hope the runs eventually improve on this aspect aswell. 

 

The displacement on itself can be helpful (so to speak), but I will wait for the "warming+after warming" period to get within the ECMWF domain, so we can see some model-to-model consensus. 

 

Best regards. 

 

[Interitus]

 

The only words of caution I will throw in at this stage (something I commented on last week too) is that with Wave 1 displacements it can be a bit of a lottery. What we are hoping for is that the vortex becomes displaced towards the Siberian/Scandinavian sector as the Wave 1 takes effect. But it would be foolish not to point out the risk of any potential Wave 1 displacement simply pushing the cyclogenesis associated with the upper vortex in to the Atlantic and leaving us in need of a minor miracle (secondary minor warmings could potentially provide such a service). At this stage that all remains conjecture as nobody can tell the exact longwave setup across the Northern Hemisphere for early February this far in advance, but it is a risk that we should be prepared for.

 

One thing to bear in mind is that more splits tend to occur following large wave 1 anomalies than wave 2 (i.e. wave 1 is more common) - see Harada et al http://journals.ametsoc.org/doi/pdf/10.1175/2009JAS3320.1 and confirmed by examining the MERRA data. Seeing wave 1 forecast doesn't necessarily mean displacement.

Edited January 16, 2014 by Interitus

[snowking]

One thing to bear in mind is that more splits tend to occur following large wave 1 anomalies than wave 2 (i.e. wave 1 is more common) - see Harada et al http://journals.ametsoc.org/doi/pdf/10.1175/2009JAS3320.1 and confirmed by examining the MERRA data. Seeing wave 1 forecast doesn't necessarily mean displacement.

I'll have to have a full read through when I get a chance but that's both interesting and encouraging to hear!

 

SK

[Tamara]

I posted in the MOD thread a couple of times in the last week or so about the possibilities of further vortex energy transport back across the pole in association with the trop/stratosphere events and summarised the risks if wave 1 activity wasn't strong enough either/ and/or was not followed up soon by wave 2 activity.

 

Its a case of keeping watching and waiting - the current model disposition towards attempted trough disruption in association with the Scandi High is encouraging on the basis of just one meaningful attack so far on what has been a very organised and strong vortex, much as posted earlier today.

 

Upcoming wave 1 activity could then be viewed more positively in terms of risks of vorticity being pushed into the atlantic if energy is transported across the pole from Canada to Siberia. (If that was/is to be the evolution) With the presence of heights remaining to the NE and a continued programme of trough disruption then might we not see amplification in the atlantic behind such trough disruption and then ridging extending and linking across to pull those heights westward. The downside risk is energy transported instead through the northern arm of the jet stream if split energy is inadequate and there is insufficient zonal wind reduction, but we already have some split flow with further zonal wind reduction to come. That was the gist also of my posts in the last week. 

 

It at least represents the better scenario. The energy budget/zonal wind reduction will determine the outcome. We keep watching in the days to come, but further warmings will become apparent as wavelengths continue to lengthen.

 

Of course an outright SSW would be the biggest weapon, rather than any drip feed of smaller wave activity events and the shorter winter season ticking by. Though even these cannot guarantee cold for a small island. Much as we already know

[The PIT]

Reading between the lines it doesn't look too good. Perhaps everybody is looking too far out and need to look at a different time period closer say t168???

[cooling climate]

 

Reading between the lines it doesn't look too good. Perhaps everybody is looking too far out and need to look at a different time period closer say t168???

 On the contary I think things are shaping up excellently for a cracking last fewweeks of winter but that is just how I see things playing out so to speak.

[feb1991blizzard]

  On the contary I think things are shaping up excellently for a cracking last fewweeks of winter but that is just how I see things playing out so to speak.

 

Do you (or anyone other regular on here for that matter) think that the warming shown on recent runs  on our side of the pole while the other side continued warming may be the start of some wave 2 activity?  One downside is the warming does seem to be subsiding at 1mb now.

[feb1991blizzard]

The strongest warming at 10mb of the day out of the 4 runs.

 

 

Although Vortex remains firmly in tact and over the pole though I cant help thinking that surely that warming would have to have an effect if it verified.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014011618&var=HGT&lev=10mb&hour=384

 

 

Particularly as the 1mb chart looks very good.

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014011618&var=TMP&lev=1mb&hour=384

 

All speculation of course at that range and cant help feeling that 10mb chart is an outlier rather than a new trend, the other charts of today are far less pronounced and the warming spread over different areas.

Edited January 16, 2014 by feb1991blizzard

[lorenzo]

Terrible chart...

 

[mountain shadow]

Right on queue for the end of the month too.

[bluearmy]

Like the Berlin output. Zonal winds low down look great and the strat split as high as 20hpa late on . Would be nice to see that repeat, especially when we have a monster depression headed east at the same timescale (could do with that hitting ed's invisible split vortex brick wall!)

[Ruben Amsterdam]

Like the Berlin output. Zonal winds low down look great and the strat split as high as 20hpa late on . Would be nice to see that repeat, especially when we have a monster depression headed east at the same timescale (could do with that hitting ed's invisible split vortex brick wall!)

 

Yes, very encouraging with a nice split in the lower strat. Although wave-2 activity is deminishing overall, wave-2 is still active/present in the lower strat/trop. In fact, it may be the highest wave-2 activity lower down I have seen this winter.

 

[weatherguy]

Hey all, is this what wave-2 activity looks like?

 

 

With 2 different centres of warming at opposite sides of the vortex?

[MattH]

Posted this on twitter earlier today, but finally something to at least analyze when it comes to the MJO after weeks of it being an almost unusable guide as to possible up coming broader patterns;

 

https://pbs.twimg.com/media/BeLjLNVCIAAtqkz.png:large

 

Clearly the 06Z GFS Det and the Control look outliers medium and longer term, but it is interesting none-the-less that they were signalling blocking to the W and NW of the UK, as per phase 6/7 for a January month with a cold N or NW'ly flow over the UK, with time. It's just another piece to the puzzle, as mentioned within the document, but there continues to be an increasing signal and amalgamation of variables that all point towards a greater, heightened risk of colder weather developing with time as the broader synoptic patterns become somewhat more favorable. If we can obviously get the start vortex down on it's knees as well, then as many have been barking on about for weeks now February and potentially into March could provide the long awaited threat of cold weather that the "cold fans" have been waiting for and personally it is just another bonus to see the MJO being forecast to head into Phase 6 and 7 within the next 7 to 14 days.

 

Cheers, Matt.