Stratosphere Temperature Watch 2013/2014

[bluearmy]

The navgem strat modelling does confuse me. I have noticed that its modelling at 10hpa has been pants all winter. I wonder how it can make a decent fist of its trop modelling, given it cant have had a large cold strat vortex.

[Guest I'm a superstar]

Here's January's from the MetOffice

 

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

 

December:

 

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean2013.html

 

1.7c and 2.1c above average. That's as far from the norm as a 1 month constant cold spell is.

 

 Both 2,1c and 1,7 above average is not that much, i mean if a month has 3-5° above average temperature then that would be special/something to care about but those numbers just show the winter has been " little" mild". Not extreme or severe.

[Ruben Amsterdam]

With January almost over, and February about to start, time is running out for any serious winter attemps (last March was something exceptional, we cannot assume that month will repeat itself any time soon). A reforming vortex at this point would most likely mean the end for any true winter aspirations. Allthoug a cold snap is always a possibility, of course. The next couple of days will therefore be very interesting stratospherically.

 

Because the last couple of GFS runs seem to differ wildy in FI (or UGKB in Dutch - after the German "UltraGlasKugelBereich"), I'm inclined to say it's anybody's game at this point. The critical point (at which the runs start to deviate wildly) appears to be around the +180hrs -- +192hrs mark now. A crucial point as +192 is where the high res. ends. Tomorrow's runs (both Berlin and GFS) will be very interesting indeed 

 

Any news from the GEFS, Recretos?

 

To end, todays 18z +192 chart shows a modest split at 10hPa (it splits earlier, actually). The million dollar question is: what will happen next? Gentleman, place your bets 

 

Edited January 28, 2014 by Ruben Amsterdam

[syed2878]

1 thing makes me wander is this. I thot with a good eurasian snow cover it should of aided the warming of the stratosphere or have i got that wrong? Another thing could it be the lack of ozone moving northward prevented the warming of the strat and there for we have a stronger pv? Because if i'm rite then we did have a good october snow cover in the nh and that if i'm rite should of had some kind of feedback effect on the nh strat.

Edited January 29, 2014 by AVFC.

[Recretos]

Look at the 00z op. run if you are interested how the ensemble mean looks like.

 

Edit: Just got home, so I can throw it in a bit more graphical form.

The control run kinda follows the story, with the initial split, and then reformation of what is left in the FI.

 

 

 

 

 

The ensemble mean, not falling far behind:

  

 

An actual reformation like seen above in mid-Feb, would in my view mean that we will pretty much have to wait for the FW to do us some justice and at least giving us some moral compensation for all the hard time this powerhouse of a vortex gave us.

 

And I also have to give credit to the GEFS. It had a remarkable consistency and even tho the trend gets quite "watered out" with time because of the member spread, it still had a fairly decent idea of the development. Tho it is questionable how it would perform in stronger top down events. There is an upgrade of resolution in plan for GEFS and I hope it gets realized before the next season.

 

Best regards.

Edited January 29, 2014 by Recretos

[MattH]

Yesterdays 12Z ECM looks/looked slightly more promising towards the end of the 240hr period, take this for example at 10hPa

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf10f240.gif

 

Definite shift in the vortex eastwards after a possible split near 192hrs ( http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf10f192.gif ) - There is also more of a pronounced warming there over eastern areas of the USA/Canada.

 

Again not a bad chart at 30hPa this time - http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf30f240.gif - Getting the main vortex further east can only be a good thing generally, anything to get it away from over Eastern Canada/Greenland as it is now has to be some step in the right direction. Clearly for comparison here is 24hr chart;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf30f24.gif

 

Certainly a move away from a dominant vortex between 24hrs and 240hrs from the latest ECM.

 

The following continue to be promising as well;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=ha1&lng=eng#fig11

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=ha2&lng=eng#fig11 - Especially Wave 2

 

As someone mentioned in one of the posts above a crucial time frame seems to be around the end of the first week of Feb;

 

http://cdn.nwstatic.co.uk/gfsimages/gfs.20140129/00/189/npst30.png

 

The split, as evident on numerous levels, no doubt directly related to the strong wave 2 activity either seems to lead to nothing and with time the vortex consolidates, or as the ECM seems to be showing, that second region of vorticity over Greenland weakens to nothing and then the 'main' vortex becomes located over Siberia leaving this kind of pattern, which comes back to my original link;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf10f240.gif

 

Please stratospheric gods, give us something!

 

Cheers, Matt.

[bluearmy]

and yet the tropospheric vortex seems to want to vacate siberia on the recent extended ecm ens means through week 2 ? if we are going to see this 'tooing and froing' of the upper vortex centre from canada to siberia, then i dont see this as any benefit for cold conditions nw europe as i cant recall this happening over recent winters without the atlantic jet becoming stronger 

[stodge]

On the other hand, the stratosphere won't stay this cold forever - we know this. Whatever may be showing tentatively for early February, it's a pretty safe bet that warming will happen at some point.

 

For those hoping for snow, even late March or April can deliver so far too early to be dismissing such prospects. I've seen some forecasters offering HLB in March but the stratosphere is going to stay this cold right through February that seems improbable at this time

 

Tamara offered the thought the day before yesterday that when the warming does occur, it could be very rapid and very dramatic - do we have any evidence from past winters with such cold stratospheric values that warming is more rapid - it would seem a reasonable premise but I've no evidence.

[Snowy L]

1 thing makes me wander is this. I thot with a good eurasian snow cover it should of aided the warming of the stratosphere or have i got that wrong? Another thing could it be the lack of ozone moving northward prevented the warming of the strat and there for we have a stronger pv? Because if i'm rite then we did have a good october snow cover in the nh and that if i'm rite should of had some kind of feedback effect on the nh strat.

 

Eurasian snow cover rate was awful for October, largely because of the already high snow cover at the start of the month.

 

Edited January 29, 2014 by Snowy L

[karyo]

Both the 0z and the 6z GFS strengthen the vortex in the final stage of the run!

A vortex strengthening in the middle of February? Lord have mercy!

Karyo

[Snowy L]

Both the 0z and the 6z GFS strengthen the vortex in the final stage of the run!A vortex strengthening in the middle of February? Lord have mercy!Karyo

Let's hope FI unreliability works in our favour for once At least the warming is getting into the high res and ECM supports it too.

[aginob]

hi everyone

for recretos

 

hi recretos

could you please post a couple of examples of this model?

thanks !

===

northern hemisphere

gfs 500 mb hight analysis

gfs 1000 mb hight analysis

loop

Edited January 29, 2014 by aginob

[Interitus]

 

Tamara offered the thought the day before yesterday that when the warming does occur, it could be very rapid and very dramatic - do we have any evidence from past winters with such cold stratospheric values that warming is more rapid - it would seem a reasonable premise but I've no evidence.

 

No not really, the correlations between temperatures prior to warming and the the magnitude of warming and effects afterwards are generally low and not statistically significant.

It's true that the 'surprise' warming of January 2009 with the largest negative 10mb zonal wind (minimum -31.08m/s) had the lowest 30mb temperature and largest increases in temperature at 10mb and 30mb in the week before, but there is a weak negative correlation of -0.24 between this previous 30mb temperature and the average vortex winds in the 20 days after SSW - i.e. colder before ~ stronger after.

The key thing about 2009 was probably that it was associated with the highest 90° 10mb temperatures of the SSWs in the MERRA dataset which is why the change was dramatic, not the low starting point.

There is a reasonable correlation between 10mb temperature at time of SSW (which should give some hint to rises in geopotential height) with the 10mb zonal wind afterwards of -0.52 (greater warming~larger reversal).

The 10mb wind then correlates -0.65 with number of days of reversed wind in following 20 days (larger reversal ~ longer duration), and 0.55 with winds in vortex as a whole (slower 10mb wind ~ slower at lower layers of the vortex)   (edit: to be more precise this last figure should be 0.42 after removing autocorrelation of 10mb from the total, but theory still holds)

Edited January 29, 2014 by Interitus

[Catacol]

OK - time to move on. This winter wont deliver now I think. 

 

But I'm interested to try and grow a bit of knowledge about the stratospheric trends in spring. I know literally nothing about this.

 

If the vortex holds its shape through to the end of winter then does the same general rule apply as is the case in winter? Will this mean a predominance of westerlies? At what stage in the calender does the vortex over the arctic lose its significance for our weather, or does it remain important even through the summer?

 

Sorry for noob questions. I have only ever shown an interest in winter patterns before... but as this is turning into the worst winter that I can ever remember down here in the SW it is time us Somerset folk tried to think of something other than grey skies and driving rain.

[cooling climate]

The 12z intensifies the warming out to t240 it not worth looking beyond

that due to the greater inconsistency of the output. It will be interesting

to see where the ECM sits tomorrow.If the t240 charts verify this would be

our strongest wave 2 warming of the season I am sure we would see effects of

this in the troposphere and NWP charts.

I thought I would post and save the 10mb t240 temperature chart just to

see how close it comes to verifing.

[Interitus]

OK - time to move on. This winter wont deliver now I think. 

 

But I'm interested to try and grow a bit of knowledge about the stratospheric trends in spring. I know literally nothing about this.

 

If the vortex holds its shape through to the end of winter then does the same general rule apply as is the case in winter? Will this mean a predominance of westerlies? At what stage in the calender does the vortex over the arctic lose its significance for our weather, or does it remain important even through the summer?

 

Sorry for noob questions. I have only ever shown an interest in winter patterns before... but as this is turning into the worst winter that I can ever remember down here in the SW it is time us Somerset folk tried to think of something other than grey skies and driving rain.

 

A bit early but this paper gives a good description of the decline of the vortex in spring and the effects on the troposphere - http://elib.dlr.de/71036/1/Hardiman_et_al_2011.pdf

Edited January 29, 2014 by Interitus

[nick sussex]

I was wondering how good is the JMA in terms of the strat? Just looking at its latest output it does show a split at T192hrs with quite  a significant warming at the 10hpa level.

Edited January 29, 2014 by nick sussex

[damianslaw]

May seem an odd question, but what impact does increased heat from the sun have on the vortex? During February, the sun begins to make an appearance over the North Pole and by March has a strong warming presence.. does this naturally weaken the core of the vortex due to increased levels of heat in the upper atmosphere - it must be a factor which naturally results in a weaker vortex by the time we enter spring.

 

Also, when was the last winter we saw such a strong vortex in the same position it is in now? and why has it remained stuck in limbo for so long...

 

Did anyone really foresee how strong this vortex has been? I recall reading a number of forecasts suggesting a very dry winter! How wrong!

 

I'm hopeful we won't see such a strong and similarly positioned vortex next winter.

[KyleHenry]

Wave 2 effects are scheduled to begin tomorrow on the GFS 18z

http://www.Meteociel.fr/modeles/gfse_cartes.php?&ech=12&mode=10&carte=1

GFS then shows 7 days later wave 2 at 10 hPa level peaking impressively

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=10&carte=1

GFS picked up the signal for wave 1 from a long range and pin pointed the area with high precision. Same can be said for wave 2 in placement and distance also.

I see some on the model discussion thread looking at one chart in isolation with no comparison and see no wave on that day of looking. Then write off the forecasted wave.

For it to appear again the next day.

As for wave 2, if it verifies at current strength then the Northern Hemisphere will go further into flux that it already is.

No patronising meant in my post to all those here with more knowledge then myself. Felt it had to be said.

[MattH]

Once again another good set of ECM charts from yesterday, better than the day before...A trend or an outlier, but these aren't bad at all seeing they are evident within a more shorter term period;

 

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

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

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=ha2&lng=eng#fig10

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

 

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

 

The following in particular looks the best set of charts all winter to me. Note the zonal wind at 1hPa, then the 60N  10/30hPa zonal winds and what obviously stands out is some very strong forecasted EPV activity;

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php?plot=fluxes&alert=1&lng=eng

 

We shall see if this trend continues in the coming days...

 

M.

[Recretos]

It is interesting to note that there is quite a difference in zonal means between ECM and GFS. 

 

ECM is much more reversed 75N-90N.

 

 

 

While GFS is warmer in the same region of the upper strat. 

 

 

[bluearmy]

The ECM trop run yesterday was questionable. Would love to see the strat data from this mornings 00z. (Or the ens )

[chris55]

Those ECM charts certainly look interesting. Taking where we are at day one and running through,to a layman like me, there looks to be an excellent warming and subsequent vortex split. Also the warming is taking place over Greenland, something I haven't seen before.

[Severe Siberian icy blast]

The ECM trop run yesterday was questionable. Would love to see the strat data from this mornings 00z. (Or the ens )

The thing is with such strong wave activity forecast and not in the far reaches of fi , along with a decent reversal in zonal winds , when will the models begin to show these affects in our trop outlook ? Because at the minute apart from a sniff of it las night on ECM 12's we appear to be staring down the barrel of doom ! We can see from the charts matt posted there's a decent split aswel , but yet either them charts are plain wrong or we are about to see a major flip in the models ?

[bluearmy]

Remember that the model is one dynamic. The trop model is the same animal as the strat model - we re just looking at the different areas of the atmosphere on the charts we look at.

There are no signs on the xtnded ECM ens means from yesterday's 12z suite of any trop response to those Berlin charts derived from the op run.