Stratosphere Temperature Watch 2015/2016

[Cloud 10]

An impressive FI warming on the 18z for sure.

 

 

This is what it would look like on the polar cap graph if it verified.

 

[feb1991blizzard]

2 minutes ago, Chris1986 said:

Dunno if this helps, is from 12z experimental though.

Is that available in NH format chris?, I like that if it is

[Nouska]

16 minutes ago, feb1991blizzard said:

Is that available in NH format chris?, I like that if it is

The full range of NH view products here.

http://fim.noaa.gov/FIM/Welcome.cgi?dsKey=fim_jet&domain=201&run_time=18+Jan+2016+-+12Z

 

[feb1991blizzard]

Just now, Nouska said:

The full range of NH view products here.

http://fim.noaa.gov/FIM/Welcome.cgi?dsKey=fim_jet&domain=201&run_time=18+Jan+2016+-+12Z

 

Thanks.

[Chris1986]

I was beaten to posting The link darn haha. They seem to have alot of cool model data there only do 2 runs though 00 & 12 z. The verification stats are not too bad I (also on site) I just like the variety  of data presented.

[snefnug]

9 hours ago, ukpaul said:

Look at the map (small I know) and it shows the UK in blues (cooler) as per Europe, with our surrounding water pink (warmer). Northern Europe refers to Scandinavia and Northern Russia.

Wow, very small!

[Chris1986]

Gents where can I find the temp propagation charts from strat down to 1000hpa? Recretos can you help?

[Abyss]

As things currently stand are we more likely to see SSW take place or not within the next few weeks? 

Edited January 19, 2016 by -Bomber-

[Recretos]

An impressive FI warming on the 18z for sure.

 

 

This is what it would look like on the polar cap graph if it verified.

 

Actually, it would go perhaps at max to -30 to -25°. Not sure how its averaged. But it surely doesn't go to the max. temp you see on the charts.

As far as the zonal wind goes, and the easterly reversal and so on. Allow me to give you a quick crash course (again ) in stratospheric winds. 

First let me just drop the GEFS 00z trend for the zonal mean zonal winds, which is encouraging for now.

Next, let me drop the same parameter, just from the last 3 GFS runs, since there was some talk about reversals. Well, GFS is not there yet. 

now, when we talk about zonal winds and reversals and so on, what exactly is it all about? I know it must sound confusing. First lets define the wind. Each wind has components. An east-west (zonal) component and a north-south (meridional) component. What these components actually tell us, is how much or how fast the wind or actually the air has "moved" in what direction. For example, if we have a 10m/s west wind, that is 100% zonal wind. But if we have 10m/s of SW wind, that means that it moves 50% to the east and 50% to the north. And those are the zonal and meridional components. 

here is a visual example  of a SW wind. The vj is the meridional component, which tells us how much has the air moved to the north (or south, depending on the direction of the wind) and the ui is the well known zonal component, which tells us how far east (or west, depending on wind direction) has the air moved with the wind. The black arrow is the wind vector, which defines the speed and direction of the wind. In short we usually call zonal u, and meridional v components. Those are also the official definitions in model parameters. 

Now as far as our strat goes, when we talk about the zonal mean zonal wind, we mean the average zonal component along a latitude line across the globe. The most used example for the strat is the 60N lat line at 10mb.
i made an example, from GFS, the 10mb wind speed, with wind vectors. I have marked in circle, the 60N lat line. And around that line is where we usually average the zonal components. here we can see that there is a lot of north-south wind movement, or winds with strong meridional components. And that automatically reduces the zonal wind speed, because there is not a lot of eastward movement along that line. 

A bit better example is if I change the perspective. We can see how the wind moves generally eastward, but with a lot of north-south movement, due to the wave1 pressure which bends the polar night jet. What is interesting, is that there is little to no westward movement, or zonal reversal as we call it. The main reason why the GFS largely reduces the zonal wind speed, is due to the increase in the meridional component. Or basically the wind blows more in the north-south than west to east as in a perfect zonal example. 

And an example from GFS, how an almost perfect zonal flow looks like. We can also see this increase on the ECMWF zonal mean zonal wind plots. That plot basically does the same job as my graphic, with the exception, that my graphics shows you exactly where and how much zonal or meridional wind is there at a certain level at a certain point in time, while the ECMWF plot basically just averages all the zonal components from left to right on my graphics and shows you the average zonal component. I also added the same plot for GFS, which practically tells the same story, just now you actually might now how it looks in reality on the normal lat/lon charts.

 
 
Now if I plot only the west-east or the zonal component, this is how it looks. This tells us how much and where the air moves on a west-east or left to right line. The positive values indicate a westerly wind, while negative values mean an easterly wind. The meridional component then defines if a wind within a negative region is a NE'ly, or a SE'ly. The zonal components define the W and E in the name, and the meridional components define the N or S in the name of the wind. Here we can see that there is basically no zonal reversal going on, 

Now when we talk about the zonal reversal at 10mb 60N, we do not mean an actual wind blowing in a straight line from east to west, but just simply the majority of the zonal components being reversed, so the wind is NE instead of NW, or SE instead of SW along the 60N line. We basically average (zonaly from left to right) all the zonal components, to see which one is the dominant one. Now the point of this reversal is not in the very wind itself, like the usual "we need that -1 m/s average zonal component, or else there is no SSW and no effect"... There is hardly any difference between a +1m/s average zonal component or a -1m/s average zonal component. except for the purposes of classification and so on...

The very point of this reversal is somewhere else, and that is in the fact that as we see how dominant the zonal winds can be in the stratosphere, at that notorious 10mb 60N line (which above indicates a strong vortex), we know that it takes a whole deal of energy, both potential, thermal and kinetic and effort to actually reduce and reverse those zonal components. So the very deal is more as this zonal components being an indicator of the strength of the polar vortex or the polar anti-vortex, or wave activity, or the stratospheric polar high, and so on. When we see the reversed zonal components, where there was +50m/s a few days prior, you know you have a strong and intense process happening in the stratosphere, which can potentially affect the troposphere. So thats why at least to me, its not about the wind if its +2 or -4 or so on, but how fast and how much does the zonal component change, which i use as an indicator of the strength of the processes happening. 
We also must note, that sometimes when we have strong wave activity, more likely in a wave 2 scenario, the zonal winds can actually increase due to the increasd pressure gradients as the two highs press against the vortex, which by default fights back, and we can sometimes see the vortex actually intensify with a wave 2 activity, especially if the wave 2 is shorter-lived and can leave a stronger vortex behind. So not all wave activity is always good. generally speaking. but as a rule, just remember that the more wave flux you have, the better. 

As for the downwelling itself, which in this case is not mentioned very often, but that is normal since there is nothing in reliable time frames to talk about. We have to take the connection of the trop-strat into consideration here. is it coupled, is it decoupled? Because if you get a downwelling SSW of a medium strength, which is the most common, in my personal view, it is better to have a coupled trop-strat (logically) preferably a positive AO. Why? because if you have a positive AO, the chances are the tropospheric and the stratospheric vortex are strongly coupled. And as the upper one goes to sleep, the chances are better for the lower one to get hit in a similar way by the "destruction wave". Think of it a as a "channel" connecting the strat and trop polar vortex. 
Where in a situation where you have a decoupled trop-strat, with no clear definite connection between the strat and trop polar vortex, the upper vortex might fail, but it could not have as much effect on the trop vortex, since it already spins in its own regime, more than being dominated by the strat vortex like in a moderate to strong +AO situations. The effects of an SSW can still come, but might have unwanted effects on the general circulation patterns, basically causing warmer weather in UK and Europe instead of cold, and can sometimes even disrupt the cold patterns already in place. And that is not a coincidence, because if there was already a cold pattern in place, chances are good it was in a negative AO, and if an SSW happened and downwelled at that time into a decoupled system, it could disrupt the circulation and actually cause a shift in wave numbers and positions in the troposphere, enough to create a warm pattern out of a cold one. So there is a reason why sometimes (not that often but it can happen) SSWs can actually cause warm weather instead of cold. We also know that the effects of SSWs are not instant, but can vary from a few days to two weeks or more roughly. So each situation needs specific analysis. 

This is just some of my thinking, which is not necessarily the same as someone else's, but it could serve you as a guideline or as a basic explanation of why and how strat works the way it does.

best regards

Edited January 19, 2016 by Recretos

[booferking]

SSW looks like it is taking place to late keeps getting pushed out i like march weather to be more spring like and SSW to take place in Dec golf season is starting soon winter just seems to get pushed out later every year and most of the time not happen at all.

[nick sussex]

Thanks for another great post Recretos.

Yes in terms of the positive AO and SSW.  The research conducted did show a stronger trop response with the AO positive at the time, the effects lessened as the AO drops towards neutral and then in the negative AO state even less.

This I suppose is quite logical because in effect theres not as much fuel to ignite. Or perhaps a better analogy the balloon isn't as blown up so when you stick the needle in this being the SSW theres less pop!

[jethro]

I never thought I'd say this but....I'm actually beginning to understand the content of this thread. Recretos you're a genius. Not just for what you know about this subject, but for explaining it in such a way that it gets through my senile, dullard brain and makes sense.

Thank you!

[Interitus]

Good post Recretos, though with a warming like 2009 there was nothing ambiguous about an easterly zonal wind component in excess of 30 m/s on 28th January.

Also for those that might not be sure,  counterintuitively the 50% north and east directions of a 10 m/s sw wind are 7.07 m/s

[Yarmy]

6 minutes ago, Interitus said:

Good post Recretos, though with a warming like 2009 there was nothing ambiguous about an easterly zonal wind component in excess of 30 m/s on 28th January.

Also for those that might not be sure,  counterintuitively the 50% north and east directions of a 10 m/s sw wind are 7.07 m/s

 

Because cos (pi/4 radians) = 1 / sqrt(2) = 0.707 so 10 * cos(pi/4) = 7.07 m/s (in case anyone's wondering )

[wishingforsnow]

So basically, a SSW occurring in a mild weather pattern has more chance of producing cold conditions?

[Recretos]

1 hour ago, Interitus said:

Good post Recretos, though with a warming like 2009 there was nothing ambiguous about an easterly zonal wind component in excess of 30 m/s on 28th January.

Also for those that might not be sure,  counterintuitively the 50% north and east directions of a 10 m/s sw wind are 7.07 m/s

Thanks guys.

Well, i was giving a general example of a -1 and +1. of course the magnitude of -30m/s is on a whole different scale, which requires a complete breakdown of the vortex, and establishment of a polar anti-vortex. 
2009 was a beautiful example. here are some graphics of that date, and we can see the strong easterly flow being present along the 60N line. 

 

 

Edited January 19, 2016 by Recretos

[Cloud 10]

@Recretos

 

Regarding the GFS polar cap 10mb temps,is there a reason it won't verify (if taken at face value) other than the fact the chart is way into FI?

Looks to be about -76C over the pole at the moment which ties in well with the JMA graph.

 

 

[EastYorkie]

I see there has been a big volcanic eruption on the North East Coast of Russia bordering the north eastern Pacific, a place called Zhupanovsky.

Given its location, is this likely to have an effect on the warming of the stratosphere ?

Just interested to know peoples experience of this kind of thing.

[ukpaul]

23 minutes ago, EastYorkie said:

I see there has been a big volcanic eruption on the North East Coast of Russia bordering the north eastern Pacific, a place called Zhupanovsky.

Given its location, is this likely to have an effect on the warming of the stratosphere ?

Just interested to know peoples experience of this kind of thing.

Reports say the ash cloud reached 8km, so at the very lowest level of the strat if close to the poles.

The 1815 Tamboura eruption which helped to create 'the year without a summer' in 1816 had a column that reached up to 45km so clearly this is of a very much smaller magnitude. Whether it will have some effect of a lesser degree is something to keep an eye on.

[Recretos]

@Cloud10 

What I am trying to tell you, is that you must consider the fact that the JMA graphs, like the NOAA graphs are area-averaged. They probably avrage the whole area from 60N-90N, Or 65N or something like that. Your estimate went up to -8, which was the maximum temp on the chart, and not what the JMA would get if they averaged the whole polar cap from 60N to 90N. Even if the very spot of the north pole at 90N would be taken it is still a too big estimate. You must average the entire area to get the temp for that graph, not just the highest temps.

 

[karyo]

Looking at the 30hpa level the 12z gfs has significantly downgraded the stratospheric warming.

The last 3 runs had deep orange colours but noting like that in the 12z.

[Weather-history]

17 minutes ago, karyo said:

Looking at the 30hpa level the 12z gfs has significantly downgraded the stratospheric warming.

The last 3 runs had deep orange colours but noting like that in the 12z.

 

On 17 January 2016 at 1:28 PM, karyo said:

Sadly the meto 30 dayer has changed to day to something a lot less interesting.

The main positive I see in the models so far today is the stratospheric warming causing a vortex displacement towards Asia but this is still too far away (300 hours).

 

On 13 January 2016 at 11:05 AM, karyo said:

The 0z GFS had downgraded the warming at the 30hpa level but it is back with a bang in the 6z.

Caution is needed though as the 6z is often the 'warmest' run stratospherically.

Karyo

 

On 7 January 2016 at 8:03 PM, karyo said:

The nice warming from yesterday's 12z GFS has not been seen since though.

 

On 6 January 2016 at 11:39 PM, karyo said:

Sadly the 18z gfs is not interested.

Let's hope the warming returns in future runs.

Karyo

Do you only make posts in this thread with a negative tone?

[Cloud 10]

2 hours ago, Recretos said:

@Cloud10 

What I am trying to tell you, is that you must consider the fact that the JMA graphs, like the NOAA graphs are area-averaged. They probably avrage the whole area from 60N-90N, Or 65N or something like that. Your estimate went up to -8, which was the maximum temp on the chart, and not what the JMA would get if they averaged the whole polar cap from 60N to 90N. Even if the very spot of the north pole at 90N would be taken it is still a too big estimate. You must average the entire area to get the temp for that graph, not just the highest temps.

 

 

Thanks for that.

 

I had thought the measurement was taken over a relatively small area not thousands of square kms!

[karyo]

58 minutes ago, Weather-history said:

 

 

 

 

Karyo

Do you only make posts in this thread with a negative tone?

 

58 minutes ago, Weather-history said:

 

 

 

 

Karyo

Do you only make posts in this thread with a negative tone?

I am puzzled by your comment! You have obviously cherry picked the 'negative' comments. It was only last week when I was the first to comment on the 12z showing a major warming.

There are plenty of comments here when things are looking promising but then it goes quiet when the warming doesn't materialise to the extent that it was showing before which may lead to inexperienced members thinking that it is still due to happen. For example, many people in the models output discussion thread are basing their hopes in the SSW.

My comments are always based on fact whether you like them or not. :-)

Edited January 19, 2016 by karyo

[Chris1986]

35 minutes ago, karyo said:

 

I am puzzled by your comment! You have obviously cherry picked the 'negative' comments. It was only last week when I was the first to comment on the 12z showing a major warming.

There are plenty of comments here when things are looking promising but then it goes quiet when the warming doesn't materialise to the extent that it was showing before which may lead to inexperienced members thinking that it is still due to happen. For example, many people in the models output discussion thread are basing their hopes in the SSW.

My comments are always based on fact whether you like them or not. :-)

Personally I think it makes it more interesting the split in the warming. Like a boxer working the body waiting for that knock out punch the warming appears to be giving the pv a bit of a battering and previous runs cannot be discounted with regards to theme. Reality is we've been tracking this for weeks now and it would appear as if the wheels are definitely in motion albeit destination unknown, strat is currently warming and the strat trop strat coupling is in motion. The guys in here (the cleaver ones, not me) are like the winter ninjas tracking the cold down wherever it may hide  a good dose of hope helps too  

Now:-

A beating:-

End of run (still working the body) :-

Either way the pv is in the corner and on the ropes. Looking forward seeing the next few rounds over the coming weeks  

 

 

Edited January 19, 2016 by Chris1986