Stratosphere Temperature Watch 2013/2014

[bluearmy]

Not really a reverse at 60N, but a reverse nonetheless.

 

 i'd take that recretos !!

[feb1991blizzard]

The GFS 18z is a totally crap run stratospherically, lets hope the GEFS mean is better with some members showing that split that was on the 6z and 12z op run at 10mb.

 

Not even a split by 384 now, on the 12z there was one by 274!!

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014012318&var=HGT&lev=10mb&hour=384

 

 

Be interesting to find out what the ECM 32 run is suggesting.

Edited January 23, 2014 by feb1991blizzard

[KyleHenry]

GFS 18z at the 10hPa level temps peak on the 28th Jan @ -24 C with wave 1. But wave 2 pops up like a ninja two days later with -16c temps above the Ukraine (unless all the rioting and burning tyres has done this) The GFS has been showing temp rises intermittently for a month now over both areas.

Edited January 23, 2014 by KyleHenry

[Guest I'm a superstar]

A polar vortex displacement is not better than polar vortex split i think? And what if the polar vortex is weaker than normal but still there, can that lead to cold or does it need to be a split or displacement?

[Panayiotis]

A polar vortex displacement is not better than polar vortex split i think? And what if the polar vortex is weaker than normal but still there, can that lead to cold or does it need to be a split or displacement?

Well a slowed down PV will give a higher chance for MLB/HLB to occur but it may not last as long.

Edited January 24, 2014 by Panayiotis

[feb1991blizzard]

Well a slowed down PV will give a higher chance for MLB/HLB to occur but it may not last as long.

 

And also makes it vulnerable to further attacks, especially at this time of year.

[chionomaniac]

I think it is time for a mid winter stratospheric assessment to see where we are and where we might be heading stratospherically.

 

So, the story of winter so far, is one of an extremely cold stratosphere that has led to a powerful strong polar vortex that has dominated the outlook over the UK. But not everywhere due to the displacement of the vortex in the lee of the Pacific ridge, which has been an omnipresent feature this winter and has led to the east coast ogf the USA benefitting from the distortion.

 

The cold stratosphere was expected this winter - but the extent of the cold that has coincided with the Pacific positive anomaly has been underestimated and we have seen a prolonged period at the end of last Year when we entered a period of Vortex Intensification (VI). When this occurs the effect on the troposphere below is strong and this leads to a positive AO and enhanced zonal conditions.This period is most ably demonstrated when looking at the mean zonal mean wind charts - especially at 1hPa- the VI period is highlighted and the mean zonal winds reached over 80m/s for almost 2 weeks - incredibly strong and that coincided with the festive storms.

 

 

If we look further down the flux chart at the 30 hPa level mean zonal winds then another thing grabs my attention. These winds are about to reduce below 20m/s for the first time this winter. The wave 1/2 and 3 activity since the start of the year is beginning to take it's toll. One thing that I have noticed in previous years is that when the mean zonal winds at this level reduce significantly then the jet stream troposhericlally weakens and we see an increase in influence in blocking highs extending towards high latitudes. As the bike slows down it begins to wobble! 

 

So looking forward we are seeing a tropospheric pattern that I expected to see a few weeks ago (from the NW winter forecast) but the VI period has set this back a touch. The strong Siberian ridge appears to be growing in strength. The February part of my winter forecast offered 2 solutions - one based on strong stratospheric disruption and the other based on little stratospheric disruption. Well, it appears that so far we are somewhere in between. We have seen the strong wave activity so far this year that has led to the current tropospheric change in pattern and we have more wave activity forecast - but so far not enough to create a SSW. I still would not rule this out but we may not need one either. A SSW could be the difference between being at the junction where east flow meets west flow that we are seing now and putting is more towards the easterly side. 

 

We still see strong wave 2 forecast that could lead to a split in the vortex and this could just be the push and pressure that the Scandi high may need to push further west. This fits in nicely for the early to mid Feb forceast and coincides with the increase in tropospheric wave activity forecast by the Italian OPI forecast.

 

The latest GFS Strat forecast show at 10hPa how this increase in wave activity could split the vortex by day 10 and this leaves us with a good deal of promise as to what could follow thereafter:

 

 

This winter was always going to be a patient waiting game and it is now beginning to look as if that patience may be rewarded.

 

 

 

 

 

 

 

 

 

 

[Buriedundersnow]

i notice above in the post by chiono that wave 3 is mentioned and I was wondering if someone could plz give me a brief explanation of what wave 3 is and how to notice it in the charts as there seems to be a lot of it lately.

 

 

I think I have an idea of wave 1 and 2 so far with wave one being a single warming that tends to displace the vortex and wave 2 is two warmings that squeeze the vortex and is best for achieving a split vortex.

 

hope I am right.

 

but not noticed anyone showing any charts for wave 3.

 

thanks in advance to anyone who is willing to take there time to explain this and show me how to spot this within the charts.

[chionomaniac]

i notice above in the post by chiono that wave 3 is mentioned and I was wondering if someone could plz give me a brief explanation of what wave 3 is and how to notice it in the charts as there seems to be a lot of it lately.

 

time_pres_WAVE3_MEAN_JFM_NH_2014.gif

 

I think I have an idea of wave 1 and 2 so far with wave one being a single warming that tends to displace the vortex and wave 2 is two warmings that squeeze the vortex and is best for achieving a split vortex.

 

hope I am right.

 

but not noticed anyone showing any charts for wave 3.

 

thanks in advance to anyone who is willing to take there time to explain this and show me how to spot this within the charts.

Waves aren't warmings, BUS. They are exactly what we say they are, waves, and in this case extremely large planetary ones. A wave with a wavelength number of 1, if it starts at the UK, will have 1 peak and 1 trough as we pass through it around the NH before it arrives back at the UK.

 

Wave 1

 

 

Ps probably would have been better to place the axis the other way to what i have constructed through the peak and trough!

 

A wave number two has peaks and troughs as demonstrated here:

 

 

And so on and so forth. So a wave number three has three peaks and troughs - but these planetary waves are less easy to demonstrate.

[Buriedundersnow]

Waves aren't warmings, BUS. They are exactly what we say they are, waves, and in this case extremely large planetary ones. A wave with a wavelength number of 1, if it starts at the UK, will have 1 peak and 1 trough as we pass through it around the NH before it arrives back at the UK.

 

Wave 1

 

ecmwf7a12.gif

 

Ps probably would have been better to place the axis the other way to what i have constructed through the peak and trough!

 

A wave number two has peaks and troughs as demonstrated here:

 

viewimage-2.png

 

And so on and so forth. So a wave number three has three peaks and troughs - but these planetary waves are less easy to demonstrate.

 

thanks for the reply and the charts for explanation they are very helpful.

 

still trying to get my head around the strat just haven't had the time to look into it in any detail as I have spent most of my time up till now trying to understand the trop but the way I am finding things out for next winter I think I will have to make more of an effort to get a better understanding of the strat as I was a bit sceptical about it all but having read through here this year it does seem pretty key to how we fair.

[Recretos]

I was actually just about to post on wave 3 with graphics, but the power just went out. So now I wonder, how long does the post autosave last before it gets erased?

P.s.

The GEFS looks more and more wave 2-ish. Was planning to add it to the post, but now I cant for obvious reasons.

[chionomaniac]

I was actually just about to post on wave 3 with graphics, but the power just went out. So now I wonder, how long does the post autosave last before it gets erased?

P.s.

The GEFS looks more and more wave 2-ish. Was planning to add it to the post, but now I cant for obvious reasons.

So annoying that, I think that most on here have lost a long post one way or another!

[Recretos]

Well, here we go again.  Hopefully no power outage this time.

 

And so on and so forth. So a wave number three has three peaks and troughs - but these planetary waves are less easy to demonstrate.

 

 

I will continue where you have ended. The demonstration.

 

As Chiono said, planetary waves are just what the name suggests: a wave on a planetary scale. So it is not hard to recognize the wave pattern if you know what to look for. He has also nicely demonstrated how the typical wave looks like. Personally I prefer the equirectangular view (perpendicular lat/lon grid), because the waves are a bit more defined. Only visually of course. I have made some examples a while back:

 

Wave 1 on the left, and wave 2 on the right. The wave 1 lat/lon chart is actually an analysis from 28/02/1871. Not the perfect example, but It gets the point across. The wave 1 in top-down perspective is the analysis on my birthday in 2012.  It is quite a vigorous wave 1 at that point, so its a good example.

And the wave 2 charts are the 12z GFS 384h forecast.

 

 

 

 

 

 

Now as for the wave 3, things get a bit more complicated. A natural state of the vortex is wave0 , wave 1 and sometimes wave 2 (emphasis on the natural state). Each wave "requires" or induces more dynamics. So a wave 3 and a vortex disruption (intensity varies) do tend to go hand-in-hand. The wave 3 is sometimes basically more of an end result. But nonetheless, if you want to find a decent example, you need stronger amplitudes and a bit more disrupted vortex, which basically points at the upper stratosphere or lower mesosphere, since it wont be easy to find a 200-300m wave on a 10mb level.

Wave 3 can also be calculated from smaller g.height fluctuations which do not give the obvious or the expected shape on the charts, but it does appear on the calculations. All this also tends to limit its duration on the time scale.

A decent example of a wave 3 pattern was just a year ago. I decided to use the stereographic view this time, because the equirectangular view kinda looses the feeling of it, and most of the charts we look at, have this "top down" look. 

The vortex got broken up, and it almost looks like a tropospheric pattern (when ignoring that inverted ridge). You could count up to 4 waves, with one having the "wave inside a wave" kinda look. 

Keep in mind that when the vortex gets disrupted or broken up (or the wave number increases), the min/max height difference can be reduced (or the average wave intensity decreased, which is why the wave amplitude decreases with the wave number increasing), which can also reduce the wave amplitudes. This is a part of the reason why you normally don't see strong wave 1 and strong wave 2 amplitude at the same time. (Boy have I complicated this last paragraph. )

 

  

 

The recent wave 3 does seem to be more of a g.height fluctuation than an actual wave 3 pattern, so its not easy to spot it. In fact you need to go up to the peak, at 0.4mb and even there it looks more like a fluctuation than an actual pattern. And it also has that "wave inside a wave" feel to it.  But since the min/max height difference is quite big, it does not look that bad on the GDAS zonal mean graph. 

 

 

Speaking of waves, here is the wave2-ish GEFS that I was talking about before:
 

 

 

This is a "ripped off" version of the previous post, because I dont want to take any chances this time (the power just came back ).

 

Regards.

 

Post scriptum: You know, its kinda funny when I think back and I realize that just a little over a year ago, I didnt even know what wave 1/2 actually was or how to interpret the wave charts at FU-Berlin site. 

You live and learn, as they say.

Edited January 24, 2014 by Recretos

[feb1991blizzard]

Split at all levels from the start of low res onwards now on the 18z, it does reform right at the top of the strat but to nowhere near the strength and looks like a displacement underway at 1mb by then anyway.

[chionomaniac]

Another great post from our technical expert, Andrej!

 

Interestingly when looking at the chart for the 9/1/13 that you have posted it is possible to see that the there are three waves superimposed on each other here and that was confirmed when I checked back on that date.

 

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE1_MEAN_ALL_NH_2013.gif

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE2_MEAN_ALL_NH_2013.gif

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE2_MEAN_ALL_NH_2013.gif

[cooling climate]

I think it is a bit misleading to say that a wave is not a warming when clearly it is.

If you see a wave a 50,30,10mb etc there will be a warming associated with it.

[chionomaniac]

I think it is a bit misleading to say that a wave is not a warming when clearly it is.If you see a wave a 50,30,10mb etc there will be a warming associated with it.

A change in geopotential height from wave activity is not a change in temperature, no matter how intrinsically the two may be linked so it is not misleading at all, cc. It is better to be accurate and differentiate between the two, so that confusion doesn't occur.

[Recretos]

I think it is a bit misleading to say that a wave is not a warming when clearly it is.

If you see a wave a 50,30,10mb etc there will be a warming associated with it.

 

I agree with Chiono. You also have variations, like top-down warming events related with wave breaking or bottom-up wave propagations that do not necessarily mean associated warming.

And you can have some level of temperature increase because of the increased geopotential height (insert virtual temperature somewhere in here ), but that is not the same as wave-breaking induced warming that we are typically waiting for to show up in the models.  

 

For example (I just love practical examples) here you have wave 2 on the geopotential height, but only "wave 1" temperature-wise (or 1 temperature wave). On the left and in the centre you only have some g.height increased "warmth" which I could never call a temperature wave. 

 

 

 

 

Interestingly when looking at the chart for the 9/1/13 that you have posted it is possible to see that the there are three waves superimposed on each other here and that was confirmed when I checked back on that date.

 

 

As you will see, the main 2 "daughter vortices" were actually the result of the wave breaking, originating from the main vortex. I made the animation of the whole process, which should give you the exact idea.

1mb_anim.mov

 

Actually, while looking at the PV animation, all vortices did originate from the main vortex.

And on a side note, I really like the 1mb level, because with wave breaking, the dynamics look almost as intense as in the troposphere. In layman terms, its like taking the terrain of the Earth and putting it upside down in the upper stratosphere. Hint hint at mountain torques?  Kinda like spinning water in a large bucked, and then putting fingers or your hand on the water surface. If you hold your hand there long enough, it will disrupt the flow quite deep down.

That reminds me of an experiment I used to play with, when trying to simulate a mesocyclone. I used a large bucked (150l of water ), and I put some very fine dark soil at the bottom. I filled it up with water and then I spin the whole mass really fast. Then I watched how the vorticity from the large spinning water mass gets increased and focused on small specific random locations at the bottom (or like ground surface in reality) where the soil was, and it even formed quasi-funnel shaped forms. it lasted for a short period and then disappeared and reappeared at a different random location. I was basically simulating tornadogenesis by fluid dynamics.

Now you could try this at home, and when you spin up the water mass, you will notice how in the centre the water level will decrease, and on the sides the water level will increase. That is pretty much an accurate simulation of the geopotential height and now you have your own atmosphere dynamics in your bucket.  Now you put your hand top down into the water surface, deeper each time, and observe how the dynamics change with depth. It is nice if you have some very fine soil or some fine light material in the water, so you can actually see how the flow changes with depth. You can actually simulate your own SSW with fluid dynamics, which is pretty much what our atmosphere is "running on". I am also thinking of ways to simulate wave 2. I have thought about inflating balloons, but I guess I need to think some more.  I really hope someone will decide to make this experiment, because it is first hand intro into stratospheric dynamics, and pretty much as close as you can get at home to simulating stratosphere/polar vortex without a computer.

And if you make this experiment, you kinda get the feeling just what big of a player the stratosphere really is. Especially when considering that the depth/length proportions of the polar vortex are about the same as those of a "CD" disc.

 

Oh, I just wandered a bit there. Here is the PV animation I mentioned above.

1mb_PV.mov

 

And I will add temperature animation while at it. 

 

1mb_Temperature.mov

 

Regards.

 

Edited January 25, 2014 by Recretos

[Duane S.]

Signs continued strong wave 1/2 are starting to take its toll on the vortex, I;m suspecting this...

could be just the tonic we need to at least stop any ideas of re-intensification and reformation the vortex may be having. Hopefully this forecast wave2 attack will increase in amplitude over the coming days as well.

 

High up responding well to this

 

A bit further down towards the mid stratosphere, looking good as well

 

zonal wind forecast for this period looking very slack compared what has gone before this winter with a gradually more E-QBO look to the profile around the tropics 

 

The only thing that continues not to work in our favour is the EPV

Although a positive to be taken from the same chart is a continued gradual drop in wind speed at both the 10 and 30mb level.

[bluearmy]

although at day 10, we do have a split vortex above 10hpa from yesterday's run. inetresting to see that negative chunk of zonal flow seems to upwell from the trop and makes it a long way up to the extent that its olnly 15 degrees lat away from being a technical SSW. Surely something erroneous about that evolution?

Big wave 2 emanating from the trop in a weeks time. Seems to downwell its potential very effectively also.

simplistically, I would call this the best Berlin run so far.

[Ruben Amsterdam]

Decent Berlin run indeed! Also, the blue puddle of cold at 30hpa appears to warm slightly at +240 (finally!). 

 

[chionomaniac]

Wonderful descriptive post from Recretos above suggesting how we can mak our own vortex with a bucket of water!

 

No surprise to see this ECM strat run with another increase in wave 2 activity. I have been expecting the ECM to pick this up. However, there are big differences in the way that the vortex splits and reforms when comparing the runs and I wouldn't be surprised to see these differences filter through to the trop. On a personal level, no SSW forecast just yet, but the stratosphere vortex is behaving how it was suggested it would do when using the previous years analogues. I feel that we are getting somewhere in being able to predict stratospheric conditions for the season ahead - however, translating that to tropospheric patterns is another ball game completely and a lot more work is needed there!

[damianslaw]

Doesn't the polar vortex naturally weaken through February regardless of how the strat is behaving. To see any reintensification of the PV to the reach the same degree we saw it behave at the start of the year would be unusual. Indeed its strength at the end of last year was as strong as it get.

 

Also I know its a long way off, but I have heard a number of murmerings that next winter will see far more conducive signals for a warmer strat and probably a weaker PV..

[Snowy L]

Doesn't the polar vortex naturally weaken through February regardless of how the strat is behaving. To see any reintensification of the PV to the reach the same degree we saw it behave at the start of the year would be unusual. Indeed its strength at the end of last year was as strong as it get.

 

Also I know its a long way off, but I have heard a number of murmerings that next winter will see far more conducive signals for a warmer strat and probably a weaker PV..

East QBO, dropping solar flare and El Nino would be a very nice start to winter next year.

 

Edit: 06z giving us incredible temperature charts by the way. I think it might have picked up on the wave-2 signal

 

Edited January 25, 2014 by Snowy L

[feb1991blizzard]

I think we are going to get there on the 6z!

 

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2014012506&var=HGT&lev=10mb&hour=300