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Stratosphere Temperature Watch 2014/2015


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Posted
  • Location: Tilgate, West Sussex
  • Location: Tilgate, West Sussex

Please notice the difference between CB El Nino and Eastern Based El Nino.

 

The famous El Nino's of 1982/3 and 1997/1998 were east based El Nino's while 2009/10 was east based El Nino.

 

Seems to me that El Nino is becoming more Central Based in the coming weeks. We have to wait and see, what happens.

 

Sorry Sebastiaan so are you saying that all 3 were east based? Or was 09/10 central based? Just that second sentence doesn't sound right :o)

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

Here's a question for the big-brains on here;

 

Ex-hurricane Oho is currently on its way to Alaska as what will soon be a powerful ex-tropical system. Next week, another system has the potential to track right up to the high-latitudes as well (again, ex-tropical by that time). Such behaviour was seen last year but before then only once since 1949 (according to Jeff Masters via http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3150).

 

So my question is, what sort of impacts could this have in the troposphere and, more importantly wrt to this thread, could there be effects on the stratosphere as well? Would I be right in thinking that strat. impacts depend largely on whether the relatively warm air associated with the system encounters high land or some other forcing to lift it upward?

 

Many thanks in advance for your response, I look forward to reading what you have to say  :good:

 

Apologies for self-quoting but my questions seem to have been overlooked  :ninja:  

 

If a new thread starts it can be moved over there if you like, mods  :hi:

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Posted
  • Location: Slovenia, Central Europe 1050m ASL
  • Location: Slovenia, Central Europe 1050m ASL

QBO well positive, while negative phase lurking above. In the meantime, the polar night jet remains undisturbed mostly. 

 

u-componentofwindisobari.png

 

And how do we stack up against last year?

u-componentofwindisobars.png

Edited by Recretos
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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

So you guys can help me out here.

The PV is modeled to move into Greenland proper but then displace South toward Iceland.My thinking is that this wi;l cause only a temporary strengthening of the jet through Canada/US and across the Atlantic and then in deep FI troughing into Scandinavia a NW/SE aligned jet in the Atlantic.

 

Am I interpreting the interaction between the PV and potential influence on the jet/upper air patterns correctly or do you have another interpretation I should be aware of?

Edited by Mucka
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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

Well, I dont have the time for detailed explanations unfortunately, even tho I would love to write it, but instead, i decided to show you how GFS FI looks like in a more realistic way, so you can imagine it. :) basically where and how is the stratospheric vortex connected with the tropospheric one. In the transition zone between 150 to 300mb, the tropospheric effects start to get into play, so the game there is from both sides. but basically looking from 1mb down to 150mb (like where I made this 3D display), you get the clear idea where the main energy goes and where the two entities are connected. :) At least I hope that it gets the message across. :)

So as you can see, the main tropospheric extension of the strat vortex is actually the double feature, one over Siberia and the other in E'rn Canada. Looks like a "shoe", or where does the P.V. stand in the troposphere. :)

 

 

 

1.png 2.png 3.png

 

 

Very nice. Much clearer than attempting to interpret from 10hPa strat temp charts.

So would I infer from that a typical Westerly zonal flow with a flat jet-streak across the Atlantic is modeled for our local - at least in that freeze frame of the GFS 12z Op?

not withstanding that is how the Jet is modeled for 384h on checking.

Edited by Mucka
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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

New paper released this week from Dr Charlton-Perez demonstrating the ability of models to forecast strong and weak vortex conditions

 

http://iopscience.iop.org/article/10.1088/1748-9326/10/10/104007/meta

 

Also discussed here

 

http://www.bbc.co.uk/programmes/p034n5sy

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Posted
  • Location: Slovenia, Central Europe 1050m ASL
  • Location: Slovenia, Central Europe 1050m ASL

Speaking of model ability to forecast. The Euro/Atlantic wavebreaking, together with the wave 1 from the Pacific side, will make the first wave2 attack on the polar vortex, though with not much long term damage. but still, its not a bad attempt, and of course gives me the opportunity to quickly model it in 3D, where this is even better shown than on 2D charts.

 

gfsnh-0-96.png ecmwftz30nhemi229.png nhhgt30mb144.gif

 

 

You can see how the bottom strat and upper trop is being squeezed in at 300mb where the bottom layer is, with a lagged response to the mid strat. The top layer is at 10mb. I added the 10mb contours at the top to better show what is happening with the mid vortex as a response to lower dynamics. This kind of "trop infused" dynamics are almost standard for the early cold season. Lets not forget the brief low to mid strat split from December 2012. these trop waves are know to sometimes being precursos to more serious events, but we are too soon in the season, and on a bit different configuration than in 2012/2013. What I am trying to say, is that one must not confuse pure direct trop induced dynamics with the dynamics and mechanics of an SSW. Not every wave2 is the same, even if it might briefly look the same on a 10mb 2D chart. Besides, this is not a strong wave2 at all, due to its background, and its much more of a G-wave than a T-wave, which is almost a classic footprint of a brief direct trop induced wave2. 

 

Anyhow, let the animation roll, and I hope it gets the message across better than my ramblings. :) This is tho nonetheless a good opportunity to test my 3D matrix in an operational forecasting way, to help make certain dynamics more clear and to show a better picture, without having to analyse 200 2D maps. :D at least for me, but thats probably because I kinda got used looking at it while constructing it.

 

 

Anyhow, the vortex will recover, no sweat, and will avenge to the trop core, sending it somewhere in the Greenland/Atlantic sector, keeping the NAO at least neutral if not positive. 

kind regards.

Edited by Recretos
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

As winter is approaching, the stratospheric polar vortex is taking shape again. Also, there have been some very informative contributions from various posters in here over the past few weeks. One of the key factors mentioned for next winter is that we will have a westerly based QBO (Quasi-Biennial Oscillation). Although this term has been mentioned very often, so far it has left me wondering what it means. Time for some research, I would say :smile:.

 

as always V a first class and objective post from you-thank you

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Posted
  • Location: Slovenia, Central Europe 1050m ASL
  • Location: Slovenia, Central Europe 1050m ASL

Cool to have this QBO explanation. It was explained many times, but always piece by piece, or just mentioned. :)

 

The best way to look at the QBO is through a latitude cross section on a zonal mean. There you can get the best feeling where its at and how strong. I am not a fan of using zonal wind anomalies for assessing the QBO, since it is already a bi-polar feature by nature. 

 

So here is an example of a zonal mean from GFS analysis and forecast, where you can see both phases of QBO. :) The best way to look at QBO is on a logarithmic vertical scale. 

 

u-componentofwindisobari.png u-componentofwindisobari.png u-componentofwindisodbar.png

 

And analysis focused on the QBO region, and a longitude cross section, like you did with ESRL plots. :)

 

u-componentofwindisodbri.png u-componentofwindisobari.png

 

@knocker: Not sure exactly, since I hardly read any papers since 2011, but I do remember someone finding some additional features via solar cycle among other stuff, and the BDC stratosphere connection, since the QBO could connect to the troposphere also by the stratospheric and SSW dynamics. Kinda like a backdoor entrance to the troposphere. But there is more to this than just the polar vortex in this case. :)  

Edited by Recretos
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Posted
  • Location: Camborne
  • Location: Camborne

In a book I have, Stratosphere Troposphere Interactions By K. Mohanakumar he states that though the equatorial phenomenon is well understood the problem of how the equatorially confined QBO forcing can induce a signal in the troposphere and also to the extratropics of comparable or even larger amplitudes remains unsolved. Has this been resolved since the publication which was 2008?

Edited by knocker
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Posted
  • Location: The Netherlands
  • Location: The Netherlands

Cool to have this QBO explanation. It was explained many times, but always piece by piece, or just mentioned. :)

 

The best way to look at the QBO is through a latitude cross section on a zonal mean. There you can get the best feeling where its at and how strong. I am not a fan of using zonal wind anomalies for assessing the QBO, since it is already a bi-polar feature by nature. 

 

Great suggestion Recretos! Indeed the latitude cross section images allow you to tell much more than only the QBO, and also allow to put the QBO into perspective (basically it shows what a small-scale feature it is compared with everything that is going on :D ).

 

Though I agree that a logarithmic view is indeed a better approach, with the limited capacity of the ESRL plots (and lack of programming skills) I am unable to create such a scale yet. However, fortunately it is possible to create latitude cross section images with the ESRL tool. So I will update my QBO post tomorrow with some extra latitude cross section plots as an extra clarification!

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Posted
  • Location: Slovenia, Central Europe 1050m ASL
  • Location: Slovenia, Central Europe 1050m ASL

 

Though I agree that a logarithmic view is indeed a better approach, with the limited capacity of the ESRL plots...

 

Oh the good old days, of being limited to the ESRL and online plotting. :) I know exactly where you come from, dont worry. :) I was just trying to add generally for all the rest, that he best way to look at the QBO is also as a zonal mean zonal wind on a latitude cross section. i was not trying to say that your plots are not right or anything. God forbid. Keep up the good work. :)

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

 

 

With a 14-21 day lag applied, planetary wave activity over the Pacific low should allow for some moderate Wave 1 activity displacing the upper vortex towards Siberia and Wave 2 activity following end of the month into November. All in all, reasons to think that the stratospheric vortex will be on the weak and slightly displaced end of the spectrum come November.

 

 

 

 

Early tentative signs perhaps?

 

gfsnh-10-372_etf6.png

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