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Stratosphere Temperature Watch 2012/2013


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Now that is an interesting end, is that a Canadian Warming showing up?

EDIT:

Another question, at the beginning of the run as the warming starts getting drawn towards the middle of the stratosphere, this is done in an anticlockwise fashion however once disintergration of the vortex has occured on this run and if you run the last several frames, the warming and movement of the stratosphere is moving in a clockwise direction, why is this? It's like watching reverse zonality!

Edited by -eded-
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Slightly confused now.

So are we looking at a SSW or just a displaced vortex as Brickfielder mentions?

Think I may come back in January - hopefully things may be moving by then in the troposphere! Posted Image

Major SSW is looking likely, which will cause a displacement of the vortex. The vortex will then split several days after this as well though.

Interesting strat temperature from the 12z today, going for a second warming, this time over Canada. The PV must be getting fed up of this now.

Posted Image

Edited by Snowy Liverpool
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One thing I've always loved about this thread is that you used to have just the more knowledgeable posting on it, a couple of updates a day and you could pretty much use the single thread as an encyclopedia of the entire winters Stratospheric conditions.

Now in a way its a shame as its become so popular we now have 77 pages with the most informative posts being lost in general chat...may be an idea to lock this thread with just the 'invited' able to post...Chio, GP, etc with a separate thread 'Stratosphere Temperature discussion thread' opened for general chat?..............just an idea...

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I think I'm right in saying that the date of the forecasted SSW has actually moved forward somewhat, from Jan 10th to Jan 5th or thereabouts.

Bish

Based on the latest ECM forecast an SSW is set to occur on the 4th of January.

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Slightly confused now.

So are we looking at a SSW or just a displaced vortex as Brickfielder mentions?

Think I may come back in January - hopefully things may be moving by then in the troposphere! Posted Image

Where the displaced Vortex will be placed can't be said right now (it will take time for the effects will take place). So I don't see a relation between the predicted warming and Brickfielders analysis for the coming days.

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Another question, at the beginning of the run as the warming starts getting drawn towards the middle of the stratosphere, this is done in an anticlockwise fashion however once disintergration of the vortex has occured on this run and if you run the last several frames, the warming and movement of the stratosphere is moving in a clockwise direction, why is this? It's like watching reverse zonality!

That is all because of the "Polar High". I am not sure how to exactly name that anticyclone, or what its technical term is. Maybe Polar Anti-Vortex? Posted Image

Here are a few graphics, that will help you understand. Posted Image

Posted ImagePosted Image

Posted ImagePosted Image

Here I drew the "streamlines".

Posted Image

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Interesting post there from SM and no we don't think you're the new scrooge!

I think you make some good points and its perhaps because of the dismal output that this thread is turning into the Last Chance Saloon, of which I'm pleased to take part in because to be frank without this strat warming going on in the background I would be very pessimistic regarding cold and snow potential.

It's all a bit of a lottery and any warming may not provide what many are hoping for, equally we maybe surprised.

At this time we just have to hope that any blocking sets up favourably, I think with the strat warming we have a chance without that no chance of anything that resembles proper winter.

So yes its coming down to the SSW, if that doesn't deliver then its just another dismal winter, so nothing new there, I've had my share of those in the UK.

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Absolute strat novice here.

Has anyone looked at the correlation stats?

What correlates well with colder UK temps in DJF?

AO? SSTs? QBO? Strat?

What sort of lead times should you expect?

I know some think that the strat is a piece of the huge jigsaw, but how large a piece is it?

Significantly correlated or not?

What did the pieces look like in the run up to 62/3 and 2010 (admittedly snow events) or other colder winters?

Thanks

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Just acting as a counter balance-

Also the fact that I think people search to rationalise everything so much that we often forget that the main part of weather is about Timing & interaction between systems & as such even with the best will & research in the world with that element in the mix especially for the UK the signal from the stratosphere in terms of cold is always rather muted-

However typically for the UK in the end the strat always correlates when its colder than average...

S

Edited by Steve Murr
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My understanding from reading this thread is that the Srat and a possible SSW simply increases the probabilities of something colder appearing in the models. I see reasoned discussion and i haven't read one post with unreasonable enthusiasm to be honest.

Also seeing as all the split flows, and those ECM ensemble means at day 7/8 suggesting easterlies and cold have not materialized, and we look to be stuck in a very wet zonal type flow. There is no reason why we cant look forward at what may be our next shot of something more wintry. As ever looking into the future when it comes to the weather is always going to be difficult. Whether that be in the strat or the more traditional sense.

Edited by chris55
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Yes well said SK.

I think Steve is concerned that some people may be hanging their cold hat on the SSW forecasts too much and i can understand that from views that some posters have expressed.

I don`t think we can ever have too much data to look at though-the main thing is we remain aware that SSW`s don`t mean a cast iron chance of cold for the UK.It increases chances of Arctic blocking that may work in our favour-no more no less.

Whichever way the synoptics develop it`s all data for historical reference in future Winters and will add to the small sample size that Steve refers to.

Yes the activities above in the Stratosphere are nothing new but now we entering an era where we are just starting to build on our knowledge and how it impacts on the hemispheric patterns and for this we should look on this thread as a big positive for Net Weather.

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I did some pretty simplistic spatial correlation analysis of 30mb heights with the CET, the AO and the NAO respectively and while it's obviously no silver bullet there is a reasonable correlation between stratospheric heights at high latitudes and all of these measures.

AO:

Posted Image

NAO:

Posted Image

CET:

Posted Image

I find it a fascinating area of study but of course there are other factors which come into the mix as well that we can't ignore either and hopefully we can one day pull this all together and start to make the same kinds of inroads in the seasonal range as we have in the 5 day range. Is it even possible, or will we/ have we reached a point where the system is simply too chaotic to model for any specific region? I have no idea, but I'd love to find out!

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Absolute strat novice here.

Has anyone looked at the correlation stats?

What correlates well with colder UK temps in DJF?

AO? SSTs? QBO? Strat?

If you know how to interpret these correlations, I made some general AO and NAO correlations for you. If you want to see some correlations with the stratosphere (Tho very noisy), I made a post a few days ago on that.

Posted ImagePosted ImagePosted Image

Posted ImagePosted ImagePosted Image

I see LomondSnowstorm beat me too it. Posted Image Those stratosphere correlations are too superficial and noisy if you ask me. Check a few pages back (link below) where I tried to do it. It took a lot of imagination to finally filter it to get the SSW signals out, and its still not a clear signal or a clear enough correlation for someone to say "so that's where the SSW is going to strike". Posted Image I would need more time to work with the correlations to maybe get a better picture.

http://forum.netweat...00#entry2455573

But I think there were some papers written on this subject. :)

Edited by Recretos
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Thank you, Recretos, GP, LS et al!

IMO, there's one fundamental difference between stratospheric temperature anomalies (STAs) and the NAO and AO: the former, following much tweaking and analyses, may act as forecasting tools, in their own right? In contrast, the others never will; they are merely indices that are compiled after the fact. Except of course, when they are derived from whatever it is that the models are forecasting...

But, do I know who'll benefit from SSW-induced Northern blocking? Of course not. And neither does anyone else...Northern blocking doesn't always mean a Scandinavia-Greenland-Newfoundland superblock!

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Yes well said SK.

I think Steve is concerned that some people may be hanging their cold hat on the SSW forecasts too much and i can understand that from views that some posters have expressed.

I don`t think we can ever have too much data to look at though-the main thing is we remain aware that SSW`s don`t mean a cast iron chance of cold for the UK.It increases chances of Arctic blocking that may work in our favour-no more no less.

Whichever way the synoptics develop it`s all data for historical reference in future Winters and will add to the small sample size that Steve refers to.

Yes the activities above in the Stratosphere are nothing new but now we entering an era where we are just starting to build on our knowledge and how it impacts on the hemispheric patterns and for this we should look on this thread as a big positive for Net Weather.

I can see where Steve is coming from to be honest, this may be somewhat hypocritical baring in mind i am probably one of the guilty parties, as a snow and cold lover i am certainly hanging my hat on the SSW from a perspective of cold because in my humble opinion an SSW is the plan 'B' terms of getting cold and snow in to the uk after plan 'A' ie - a consistently above above average strat temp has already gone by the wayside, however it certainly is misleading and would not encourage anybody to believe that if a SSW happens then a very cold / snowy spell is guaranteed to happen, infact i would go as far as to say that if the SSW happens but the strat temps at the 10hpa level fall quickly afterwards as may happen then its is only a 50/50 shot, maybe even less (simply because HLB buckles the flow but we could just as well end up to the east of the mean trough), however, i dont think anyone on here can say, judging by my limited knowledge on this subject, that the possibility of a cold second half of jan is not significantly increased compared to normal.

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We were all very busy looking at 300h-384h periods in the stratosphere. But now I will change my focus a little bit, to the same period, but to GEFS. Posted Image Cant wait to see what its tropospheric response is going to be. Posted Image And dont worry, I am more than aware of all the "tricks" and "dangers" of ensemble forecasting and "anomaly based forecasting" in this range.

.

Animation is a bit lower quality, due to the resize.

Posted Image

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To add to what i have said, and in reply to a later post (experts feel free to say if i have this wrong), a strong SSW that probagates gives a certainty of HLB, however, no one can be sure where the HLB sets up therefore its pot luck where tha cold plunges, i would hazard a guess that somewhere in the mid lattitude will get a brutal cold spell in the next month and a half, question is where?

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Which CFS do you have in mind? The weeklies or the monthlies?

the daily ones recretos !! i'm not for one minute suggesting there's anything solid to take from them but they do show big -AO setting up, beginning sometime between mid jan and early feb. that must surely be to do with the model processing the SSW. could well be a load of rubbish but it does show how the response varies run to run.

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i know CFS runs are not bias corrected but they are worth looking through now that the model has grasped the SSW. the variation in trop response times varies from mid jan to early feb.

I read somewhere that the stratosphere-troposphere coupling is poor even in CFS v2. It might not have good idea of what happens after the SSW, then.

(Greetings from Finland, by the way. :))

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