[Stratosphere Temperature Watch 2012/2013]

forgive me for my ignorance but dosen't this warming look to far away to effect us

http://modeles.meteo...h-10-336.png?18

To put it simple, you shouldn't look at this forecasted warming as something that would have like a direct local effect. Look at it as a feature that affects the general overall dynamics in the stratosphere. So basically it affects you locally down the road, but through succession and not directly.

IMHO of course.

Edit: I add "imho" to my posts a bit often. The reason for it is, that around this time last year I had no idea what SSW stands for, and I had no idea what an SSW is. All I knew about stratosphere a year ago, was that there is a cyclonic feature a.k.a. polar vortex present up there, and it somehow affects us down here. So I am less than a year in this whole "strat business", with lots of stuff to learn, but trying to keep a high pace.

[Stratosphere Temperature Watch 2012/2013]

@Recretos, some fine analog work there, no idea how you went about creating those charts on the map room. Superb stuff.

The power of NCEP/NCAR reanalysis tool is really awesome. I got the idea to make some correlations when there was talk about snow, not really knowing how much of a common understanding it is in here.

@Chionomaniac: Thanks for the link. I will have some time to spare this weekend, so I hope I will be able to go through some papers.

I cant help myself, not to wonder, if there is such a difference in the 8-10 day period, how much of a difference can there be on the 384h up in the strat. Of course because of the different idea of the action below, there could easily be some differences in the action "above".

[Stratosphere Temperature Watch 2012/2013]

Recretos - have you seen J Cohen's work regarding stratospehric warming feedback from rate of gain of October Eurasian snowcover? This is well known and has been illustrated many times on here - it confirms what you are trying to show.

Actually I haven't read any of his papers yet. And neither have I read this whole thread. I was almost 100% that this is nothing new, but I still thought it might be interesting. Sorry about that. I will try to look around next time before I post.

[Stratosphere Temperature Watch 2012/2013]

Since NH snow cover is being mentioned, I was playing around with the correlations tool, and I think you will find the results quite interesting, especially when compared to the latest GFS forecasts.

Keep in mind that I have put a 2 month lag between the two values, giving the NH Snow cover a 2 month lead. Correlations above 0.7 or below -0.7 are very good, I would say. And of course we all know there is more than just the snow cover in the picture, when it comes to MMW's. But the correlations speaks for themselves, keeping the snow cover as an important factor, not really directly, but more in a general way like @snowking was quoting from a paper from Cohen et. al.: "

We suggest that the intensification of the Siberian high, along with the thermal impacts of enhanced snow cover and topographic forcing, corresponds to a positive wave activity flux anomaly in the late fall and early winter, leading to stratospheric warming and to the January tropospheric negative winter AO response we have mentioned above."

That is probably why the best correlation appeared when I applied a 2 month lag (Snow cover leading). Which means that the parameter period (Dec-Jan) is being correlated with the snow cover from Oct-Nov. Below on the graph, the 2012 snow cover anomaly is presented for that same period.

And latest in the "pattern" area.

Correlations.

Based on these correlations, I would say that the latest GFS forecasts are very likely to come into fruition, probably not as hardcore as they are now, but in the same "spirit".

In my humble opinion anyways.

p.s.: I used the 1980-latest(I think NCEP needs to update their correlation datasets, because the latest parameter values are for 2007) correlation period, basically because of the realistic data after 1980, when the satellite era began.

Best regards.

[Stratosphere Temperature Watch 2012/2013]

Wow. http://forum.nwstatic.co.uk//public/style_emoticons/<#EMO_DIR#>/ohmy.png This could be a major if it comes to fruition. If nothing else, at least the trend is good for now.

[Stratosphere Temperature Watch 2012/2013]

thanks for that GF - its just meteociels representation of temps only that is misleading

Yep. Its misleading because it only shows temperature. The center is still fairly good visible from the gradients and the general shape, but as others have already pointed out, the geopotential height maps are the ones you need to look at, if you want to know where exactly is the forecasted center.

[Stratosphere Temperature Watch 2012/2013]

Here is an animation I made, containing the potential vorticity from 27th November to 10th December, on the 600K theta level, which is roughly around 23km or 30mb. Images are from http://www.pa.op.dlr...tic/index.html.

It shows nice dynamics with the split, and an interesting energy transfer and reformation of the vortex.

And here is an image, that will help you understand the height of the theta levels.

Best regards.

[In Depth Model Discussion, Analysis and Summaries]

So, having read this a number of times, the ECM run, with all it's ensembles can potentially change significantly on day 11 when the ocean - atmosphere variables ( perhaps changes in MJO and El Nino) are factored in.

Don`t forget the recent kelvin wave coming on, and daily SOI values dropping below -40! So as good as they are, I would take a slight step back (for a little while) from the monthly ocean coupled models.

[Stratosphere Temperature Watch 2012/2013]

I might be young and inexperienced in life, but I can sure as hell spot a Polar Vortex in trouble, when I see one.

[Stratosphere Temperature Watch 2012/2013]

I see people mentioning 68/69. I thought I could add some reanalysis charts for a better idea of that period (even tho I think most of you already play around with reanalysis tools). Lets keep in mind that regarding reanalysis data, 68/69 is before the satellite era, but I do believe the datasets are as accurate as they can be.

In that period we were in a cold PDO/cold AMO setup, and going from negative biased neutral ENSO3.4 (basically in La Nina values but not long enough to be classified as a La Nina) in the first part of the year to a weak El Nino by the end of the year. Also worth pointing out, is the negative QBO going into winter. Adding the late November 2012 QBo for comparison.

The winter pattern composite. This is basically very similar to my statistical winter outlook, and also one of my analog years.

This is the pattern comparison between second half of November in 68 and 12. Basically not so similar, except for EU, E Atlantic and Asia. Also more ridging present over Atlantic this year, more than likely linked with the warm AMO. And the AO/NAO comparison.

The late November comparison.

Now the stratosphere reanalysis is interesting, showing a nice little displacement already in late November. I wouldn't really rely on the pre-80's strat analyses, but i guess its as close as it gets.

Each month of 1968 winter.

And last, the pre-November 500mb pattern comparisons and QBO.

ECMWF vs GFS (12z run)

http://shrani.si/f/1Z/RH/3oXv1GXV/test8.gif

CFSv2 week 1 & 2

http://shrani.si/f/J/8T/1EoTsalT/wk1wk220121129z500.gif

BCC Monthly forecast.

http://shrani.si/f/3a/yu/yBk97by/md2012116nhh5m11.gif

Best Regards.

Edit: Added Nov. 2012 QBO, 12z ECMWF vs. GFS and CFS and BCC forecast.

[Stratosphere Temperature Watch 2012/2013]

This paper below shows where blocks have occured prior to the wave events that have led to SSW's. As you can see Atlantic blocks seem to favour displacements and Pacific blocks favour splits.

Look at table 1

http://www.columbia....es-GRL-2009.pdf

Very interesting paper. I will read the whole thing as soon as I can find enough time.

I see the table 1 yes. Basically it could be safely to say that wave 1 and 2 are with respect to Atlantic and Pacific (on a general view) and with respect to displacement and splitting, as you were pointing out with your analogy.

Thanks again for your time. I probably look really stupid with these questions. I will go through some papers and/or studies to see if I can make things even more clear for me.

Best regard.

[Stratosphere Temperature Watch 2012/2013]

Yes, I understand that part. What I meant with location specific was, like for example: wave 1 is always in one specific location and wave 2 also at a specific location. As you just said, the deflection is location or terrain specific, but the number for the specific wave is given because of the order, or sequence. Or at least that's how I now understand. And that was my main dilemma: Is the number given in respect to the wave succession, or is it given to a location specific event, just for example: wave 1 only in Asia and wave 2 only in Pacific/N America.

[Stratosphere Temperature Watch 2012/2013]

Waves 1 and 2 are just the number of larghe scale planetary waves that are affecting the stratospheric vortex at a particular time.

If you imagine that the vortex is a balloon ( a rough analogy here) and you place pressure with 1 finger on that balloon then you will create a distortion similar to 1 wave or wave number 1. If yo place two fingers at opposite sides and apply presssure then that is akin to 2 waves - wave number 2 . And 3 fingers at different points a three wave pattern will be created. We are used to waves with a far smaller wavelength - such as the number of Rossby waves travelling around the troposphere - but the number deflecting the stratospheric vortex at any one time is far smaller.

Of course the polar strat vortex is more cylindrical in shape and the waves are created by higher pressures throught the depth of the stratosphere. Going back to the balloon scenario it is easier to imagine how wave number 1 can create a displacement type of event on the vortex and wave number 2 a splitting type of event.

The precursors to the waves are normally higher pressures around mounrtain ranges that can divert a tropospheric wave into the stratosphere creating a mountain torque evnt in the process. There are only so may mountain ranges in the NH that can create this which is why we don't have more than a wave 3 event at any one time.

Thank you very much. So it really is more of a sequence thing and not a location-specific event, which was my main dilemma. Thanks again for your time. And the balloon analogy was splendid!

And of course my usual ECMWF 12z "outlook".

Still the same idea. the Pacific and Greenland ridge attacking in, keeping the trop. P.V. split, WAA on their W side, with a High dominating the region, keeping the AO "down under" for now.

Best regards.

[Stratosphere Temperature Watch 2012/2013]

Thanks panayiotis. I will try to make a short explanation, because I really don't want to be too offtopic in this thread.

Basically I guess I do have some knowledge in this area. Tho my main area of "operation" is severe convective weather and general or "basic" meteorology. For the past 2 years, I am focusing more on global setups, a.k.a. ocean and atmosphere teleconnections and its influence on global patterns and pattern changes.

Last year I was only reading certain forums and gathering knowledge on the whole stratosphere matter, because I never heard of SSW before (as funny as that may sound. But I am only 21 years old and just 5 years in the great world of meteorology). But this year I decided to start writing posts to try out that gathered knowledge in practice. But the main problem is, that tho I understand the whole picture, I have some problems with the little details and small pieces in this whole strat deal. And the fact that I only had Physics for 2 years in middle school isn't really helpful. So when I came across this thread I just had to register after reading just first 2 pages. I've noticed there are people posting here, that understand the little pieces (and also the whole thing) much better than me. So here I am now, hoping to improve my understanding of the stratosphere/troposphere processes through debate and sharing opinions.

Best Regards

P.s.: And thank you all for accepting me here.

[Stratosphere Temperature Watch 2012/2013]

@recretos there is a link to technical model thread in my signature you may enjoy reading and adding your posts to. Our resident GLAAM expert Glacier Point updates in their regularly and had this recent spike well forecast.

Thank you very much. I will check it out. My knowledge of GLAAM is quite limited, so I really look forward to any expert opinion. And yea, my MJO post was a bit offtopic.

Speaking of my limited knowledge, I have a question. If anyone would be kind enough to answer it, I would really appreciate it. Its about wave 1 and 2. I basically understand the effects and everything regarding the FU Berlin charts, but I have a hard time explaining to myself, what wave 1 and 2 actually are. Is it any planetary/Rossby wave, or a specific planetary/Rossby wave event, regarding location?

Its been a long day, so I'm just going to add some ECMWF 12z charts, so I wont be totally offtopic again.

Still decent ensembles. I find it really amazing, how the ensemble mean has the 300+ gph anomaly on a 10-day range.

The CFSv2 weeklies (The only CFS that I actually take notice off), kinda agree on the ECM idea.

GEFS and BCC ensembles also having a similar idea. Basically what I am trying to show here, is that the ridge offensive on the tropospheric polar vortex doesn't look like its gonna end anytime soon. At least not in the First half of December, as it looks like.

AO and NAO forecasts:

I will end off with quoting Dr Joe D'Aleo, from his recent thoughts on SSW:

"I suspect this year will behave more like 2003/04 which has some tropospheric warming in November and early december but in which the warming above in the stratosphere began in December making January brutal."

Best Regards.

[Stratosphere Temperature Watch 2012/2013]

@Lorenzo: Escape plan? More like riding it out, if the best case scenario comes to fruition. I've "survived" temperatures below -20°C with the deep freeze in February, and more than 35 inches of snow in 2007. So there is nothing left to surprise me. (Maybe both at the same time)

@Chionomaniac. it was really interesting how that super SSW affected Europe in general. One would expect super blockings, but I guess the outcome wasn't that bad either.

Some of my thoughts on the MJO matter:

ECMWF has the MJO going more or less into phase 2, while GEFS is holding on to the phase 1 only. But basically a slight disagreement between models.

Phase 1 - Phase 2 - Phase 8

Phase 1 and 8 have a tendency for the strong Aleutian low, which I just can't get familiar with. They do have the Greenland ridging in the composite. I see a slight problem regarding the ridging tendency in the Central and south Europe.

Now these are just composites, how the certain phase looked like in the past. So I look at it more like tendencies or "pattern support".

GEFS is not really reflecting any main phase 1 features.

Now the phase 2 composite also doesn't really have any similar main features. It also has an Aleutian low, but much weaker. But, what is interesting, is all the quite strong blocking features around the polar circle, basically more favorable for P.V. split than the phase 1 composite. It doesn't have the Greenland ridge, but it has Azores ridging with a gap into the polar circle. Another important feature are the lowered heights over Europe into E USA.

Interesting enough, CFSv2 weekly ensembles, are also leaning more towards the phase 2 idea.

But given the temperature anomaly and streamfunction composite, one could say a phase 8 is more likely to occur.

We have to keep in mind that we are on the verge of a split vortex, which can make things look a bit different than the MJO phase composites. Those composites are very good for guidance and in some cases give the right idea of the outcome, but when the overall dynamics get a bit more complex, there are obvious differences with the phase composites. But I am more than positive that we all realize that.

In the meanwhile, AAM picked up its zonal "pace", going positive (but I still don't believe that an El Nino signal would appear, especially with SOI being quite positive), with GWO responding by moving in the higher AAM phases, respectively with the negative trending mountain and frictional torque.

Even tho I have a bit limited knowledge of these processes, this is how I see a possible outcome (my opinion basically):

Atmospheric Angular Momentum trending back down towards negative values, and with an MJO wave coming on, probably in the Indian ocean (Phase 1-2), GWO moving into phases 8 and then into 1, leaving mountain torque near negative. With the resulting northward momentum transport, and the negative AAM if it happens, the mountain torque should eventually re-intensify. And that would make things a bit more interesting again in a certain range. IMHO Anyways.

Best Regards.

[Stratosphere Temperature Watch 2012/2013]

Thank you @cooling climate for answering my question. Sheds a light on a few other things, not just the theta heights.

@Lorenzo. Nice one

Since the FU Berlin site has the ECMWF 12z run as "their" run, I will post some 12z charts too. Basically the same as I posted yesterday. Going to make a combination of the operational and the ensembles, so you can get the right feeling.

The idea of the northward WAA remains, so I expect the EP Flux forecast to be just as good or similar as yesterday. Notice all the CAA down into the lower latitudes.

Next up, geopotential heights.

Negative NAO flip basically inevitable. The same goes for the tropospheric P.V. split.

100mb heights for Europe and 300mb vorticity.

No changes in the AO and NAO forecasts.

AO going down, with the High building into the polar region and NAO also going down with the ridge expanding into the Iceland/Greenland area, and trough dropping into W Europe (refer to the graphics above).

Now as Mr. Chionomaniac pointed out, the tropospheric dynamics can have a bigger impact then upper activity. I will show you the case of Nov-Dec 2008, using the NOAA reanalysis tool, just to show some similar dynamics or tropospheric "activities". Or at least that's how I see it. The time frame is a bit different, but the main focus is on the dynamics.

Pattern for late November-mid December 2008, compared with 18z GEFS mean anomaly. The main difference with this years evolving pattern, is the stronger or more northward oriented Greenland blocking and a bit weaker Siberian High.

As this year, and many others, stratospheric vortex was nicely organised and in place prior to that. Center temperature down to around -75 to -80 Celsius, with "warm" outskirts around at -50 to -55 Celsius.

With all the dynamics down below, especially the expanding Aleutian and Siberian ridges (with some help from the Greenland High), the tropospheric vortex split up, all the way into the lower and mid stratosphere,

Comparing the 2008 case, and the GFS forecast for 2012. As I said, the time frame is different of course, because there are never two totally the same events. So the main focus is only on the similar (not really the same) dynamics.

Later on, the ridging/blocking persisted, keeping the P.V. split, while it was trying to reform in the mid stratosphere.

This first disruption then ended with the reformation of the whole vortex in a week or two. But what followed in January was an SSW of epic proportions, of course with other dynamics involved.

This was just to point out, how similar dynamics below, can usually have similar effects on the stratospheric polar vortex. And I am not trying to say that we are going to have a super SSW in January. That was a story on its own. But hey, who would say no to a super SSW, right? http://forum.nwstatic.co.uk//public/style_emoticons/default/good.gif

I apologize if I posted too many graphics, or if the post is too long. As you will probably find out soon, I find it much easier to share my thoughts, if I do it in a slightly longer way. And I have to add that all above is nothing more and nothing less then just my thoughts, observations and/or opinions.

Best regards.

[Stratosphere Temperature Watch 2012/2013]

Looks like there will be a decent amount of WAA into the polar circle, on the west side of the Azores High expanding into Greenland. And also from the south flow on the west side of the Aleutian blocking.

Also a positive factor is most defiantly the warm AMO.

As a result of the overall activity, AO and NAO currently forecasted to "plummet", as one would expect from movements and pattern changes of this magnitude.

Things really shaping up.

Best regards.

P.S.: Would someone please be kind enough, to explain the theta levels in mb height? I understand all the charts and graphs on the FU Berlin site, but I just can get the right idea of the height of the theta levels, on which vorticity is presented. I have the idea of Higher theta-lower heights, but cant get the idea of the actual height. Google wasn't of much help either.

[The Seasonal Forecast Thread]

Hello.

This year I decided to make a seasonal "outlook" of my own. I guess its a statistical forecast, because it is based on reanalysis. This is basically just a composite or a blend of the winters in the past. I used certain winters and blended them together. I have chosen the years and months, based on the overall global setup and similarities in the oceanic and atmospheric features. The graphics were made on October 29, when I finished my analysis process and first published on November 1st on a weather forum in my country. So lets say I have 1 month "lead time" before the start of the forecasted period. This is my first attempt of "statistical" forecasting, so I don't really expect much success to be honest, but I need to test it, so i decided to make a "public test", by posting it on different weather forums.

Some interpretation is required. This is basically an average picture, like an ensemble mean, so it has its respected deviation and variance. But just the average or "middle" picture will suffice for my first attempt. I posted this on a forum in my country, so the text on the graphic is in my language (Slovenian). But some words, like the names of the months are similar, so I think you will understand what period is represented on the graphic.

I am only aiming at the DJF 500mb geopotential height anomaly for the verification in March, when the forecasted period is over.

Now the graphics. Keep in mind that this is unaltered in any way. And it was made in the end of October, when none of these features were present in the seasonal models. At least not in this magnitude.

Corresponding precipitation anomaly:

And temperature anomaly:

And I will also add the December 500mb height anomaly, made on the same date with the same system.

And this was CFSv2 when I made these graphics.

I first posted these images on a weather forum in my country, on November 1st. And all the graphics were made before that. Here is the link to that topic to prove it. Basically so no one can say that I "cheated", by looking at current models (which differ anyway) and intentionally making a similar picture.

Best regards.

[Stratosphere Temperature Watch 2012/2013]

First I have to say Hello! New to this forum, and found this topic while I was searching for some stratosphere info on the web. Thank you Google. Quite a debate I must say, on a real high level. I wont interfere with your debates, so I am just going to share my thoughts occasionally. My first post post might be a bit sluggish, but I promise I will try to get in the overall flow of this topic.

Things seem to be on a roll (no pun intended) against the polar vortex, or at least that's how I see it. Better defined easterlies starting to appear.

Not that surprising, given the High building into the polar circle. I find it quite amazing how the ensemble mean is still keeping a 300+ anomaly on a 10-day range. Talk about ensemble consensus.

Looking "cool", temperature wise.

Now as it was already pointed out, it looks like the P.V. will reform after this split-up that is being almost literally thrown in our faces by the models.

I don't want to speculate or anything, especially because its quite far out. But am I the only one glad to see this appearing in the models? And I am sure you have all seen it already.

This is a bit awkward post, but I promise I will improve with time.

Best Regards.