Stratosphere Temperature Watch 2011/2012

[cooling climate]

From what I can gather when we see 500 mb heights extending up

into the Arctic from the Pacific side or Atlantic side it is because of

the blocking alreading having taken place in the higher troposphere

with the planetary waves then downwelling into the stratosphere and

the then subsequent warming taking place.

Why this can not happen at the moment is the question I think.

Is it I wonder anything to do with a lingering +QBO in the upper

stratosphere and also below 50 mb which hopefully will have gone in

another few weeks or is it that we have not seen a big enough MJO

wave or mountain torque event. I am of the belief that a +QBO responds

to a much bigger forcing IE solar forcing.

looking forward to any replies.

[chionomaniac]

hi chiono, what do you make of that study? considering there has been sustained blocking in the pacific lately

One of the crucial parts in the conclusions is the fact that there were 782 blocking episode between November and April and only 52 of these were precursors to SSW's. So that left 730 blocks that didn't produce. But at this point a lot more research is needed to determine the influence of the blocks to wave patterns and deflection of waves to the stratosphere that didn't become SSW's but still had some sort of effect.

So presently, I do not think that the block in the Pacific will lead to much.

Just curious but if you get an SSW with an active MJO, would this tend to amplify the effect if in the correct phases?

Not thinking as much as last December but maybe something approaching January or February 2010.

I also note that the QBO at 50mb actually saw a value of +11, has this been dropping or continuing to rise.

I think we have seen previously how important it is to have everything in place following SSW's, because the studies have shown that they do deliver but there is no guarantee where. So bring on the right MJO phase after a SSW!

Importantly if you compare the remnant of the residual westerly QBO that I made at the start of this thread to now one can see that it has reduced. That is encouraging and one of the hopes that I hold out for later this winter.

From what I can gather when we see 500 mb heights extending up

into the Arctic from the Pacific side or Atlantic side it is because of

the blocking alreading having taken place in the higher troposphere

with the planetary waves then downwelling into the stratosphere and

the then subsequent warming taking place.

Why this can not happen at the moment is the question I think.

Is it I wonder anything to do with a lingering +QBO in the upper

stratosphere and also below 50 mb which hopefully will have gone in

another few weeks or is it that we have not seen a big enough MJO

wave or mountain torque event. I am of the belief that a +QBO responds

to a much bigger forcing IE solar forcing.

looking forward to any replies.

I have not researched the solar forcing part but certainly agree with the rest of your post cc. There is more than one way that planetary waves affect the polar vortex as can be seen in the link given on this subject a day or two ago.

Edited November 20, 2011 by chionomaniac

[bobbydog]

One of the crucial parts in the conclusions is the fact that there were 782 blocking episode between November and April and only 52 of these were precursors to SSW's. So that left 730 blocks that didn't produce. But at this point a lot more research is needed to determine the influence of the blocks to wave patterns and deflection of waves to the stratosphere that didn't become SSW's but still had some sort of effect.

So presently, I do not think that the block in the Pacific will lead to much.

I think we have seen previously how important it is to have everything in place following SSW's, because the studies have shown that they do deliver but there is no guarantee where. So bring on the right MJO phase after a SSW!

Importantly if you compare the remnant of the residual westerly QBO that I made at the start of this thread to now one can see that it has reduced. That is encouraging and one of the hopes that I hold out for later this winter.

thanks for that chiono,

i got the impression from reading it, that it was a bit more positive, but i suppose that was just wishful thinking lol

rob

[summer blizzard]

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=f240&var=u&lng=eng

Looks like weak easterlies at the surface forecast, though not strong enough to unhinge the polar vortex.

[DT-wxrisk]

Sorry folks but the fact is Joe B is a clown and Hypster of the first order.

2 weeks ago That Moron was banging the drum about how it was going to turn MUCH colder after NOV 15....

instead we are looking at temps i the 60s and 70s over MUCH of the eastern CONUS NOV 20-30....

Hi G.P,

There is a lot of talk over on Weatherbell (Joe B and Joe D) concerning a pattern change early December (obviously this is skewed towards the US) though they are expecting a rise in heights over southern Greenland:

For a change the ensemble means provide a more realistic solution with the North Pacific cold trough with an axis extending south west of 150W. Note the warmth in northeast Canada and southern Greenland reflected a tendency for blocking. Also the nosing ridge feeding the Great Basin high which helps deflect cold air south the east.

The spaghetti chart which shows the 516, 546, 576 and 588 gpm height contours for each of the 21 ensemble members. Climatology is shown in green and ensemble mean in orange for those contours. White depicts the operational 18Z run. See how again the op run was an outlier. The majority of members are suggesting a central US trough which corresponds to the Pacific trough location anchor.

One of these days soon, the op runs will reflect a change colder late this month and early December.

BTW, this is the second straight GFS ensemble showing this tendency. It has more eastern Canada blocking.

See 16 of the individual members. Almost a third were impressively cold..

I note that the emphasis of these discussions are in relation to the US situation, but a pattern change nevertheless. Just wondered what your thoughts were or, if I have (most likely) latched onto the wrong end of the stick.

Interesting that the Weatherbell talk over recent days has been for December cold to begin to take hold (US) with a gradual cooling of central Europe into the NorthWest later ...... sounds possible this may be similar to your own thoughts but just a little sooner ?

Cheers

Y.S

Edited November 21, 2011 by DT-wxrisk

[summer blizzard]

Chino, i notice that the ECMWF is forecasting the current statospheric warm anomaly over Asia to move into the Pacific, will this make any difference or will the fact that it does not break through to the pole just mean that it is meaningless.

[chionomaniac]

Chino, i notice that the ECMWF is forecasting the current statospheric warm anomaly over Asia to move into the Pacific, will this make any difference or will the fact that it does not break through to the pole just mean that it is meaningless.

The warm anomaly is minor and is riding the 'surf zone'. The surf zone is the boundary between the strongest area of potential vorticity and no potential vorticity immediately south and creates quite a blockade to the entry of warmer anomalies and ozone into the polar vortex. However, it is not totally impervious even to lesser assaults than wave breaks that cause SSW's. This warm anomaly does create a slight pressure distortion that distorts the polar vortex but this is only minor.

Any distortion or ridge at the 30 hPa level does not necessarily mean a ridge at the 100 or 1000 hPa level. It has been shown with 3d analysis that the potential vorticity maximum areas spiral around westwards inside the polar vortex as the vortex increases in height. So a blocking area over the Pacific at 30 hPa may translate as an Atlantic block at 100 hPa at the tropopause. Of course the spiralling nature may be more or less exacerbated than that.

[chionomaniac]

The first positive for cold lovers for a while Chiono?

I wondered,as i am new to this part of meteorology,is this an upwelling wave from the Tropics,maybe caused by a Mountain torque?

The reason i am thinking this way is the forecast warming seems to start at 100hpa as early as T120 here,

http://wekuw.met.fu-...st=f120&lng=eng

and then the warm area seems to show it`s hand higher up as the timeframe goes on to T240hrs. at 30hpa --as you have shown.

Maybe i have got this wrong and what i am looking at are isolated patches of warmer air circulating around at lower levels.

Be glad of your input,

Regards,Phil

Phil, you asked this question some time ago and I have now done some more research on the answer.

Basically there are two mechanisms for wave breaking into the stratosphere. The first way is that a wave travels around the edge of the stratospheric polar vortex and then goes down over the top. The second is a tropospheric wave breaks up from the troposphere through the middle of the stratospheric vortex.

It is technically explained better here: http://www.columbia....Volume-2010.pdf

"Three-dimensional (3-D) simulations of a forced vortex show two classes of wave breaking: “remote†wave breaking where Rossby waves propagate up the vortex edge and break in upper levels (e.g., Figure 5c) and “local†breaking where the wave breaking occurs at lower levels of the vortex and inhibits further wave propagation into the upper levels [Dritschel and Saravanan, 1994; Waugh and Dritschel, 1999; Polvani and Saravanan, 2000]"

Looking at the last couple of years it is my reckoning that the Feb 2009 event was an over the top type and the last two winters have started off with the centrally positioned upward tropospheric wave breaks. It is these that have given the better blocking and better chance of cold. This January I wouldn't be surprised to see an over the top type wave break that leads to a SSW.

Edited November 21, 2011 by chionomaniac

[Kentish Kiwi]

This January I wouldn't be surprised to see an over the top type wave break that leads to a SSW.

Which you believe is less conducive to sustained blocking in areas that impact the UK then a vortex split like the last two? (in terms of bringing colder weather)

[phil nw.]

Phil, you asked this question some time ago and I have now done some more research on the answer.

Basically there are two mechanisms for wave breaking into the stratosphere. The first way is that a wave travels around the edge of the stratospheric polar vortex and then goes down over the top. The second is a tropospheric wave breaks up from the troposphere through the middle of the stratospheric vortex.

It is technically explained better here: http://www.columbia....Volume-2010.pdf

"Three-dimensional (3-D) simulations of a forced vortex show two classes of wave breaking: “remote†wave breaking where Rossby waves propagate up the vortex edge and break in upper levels (e.g., Figure 5c) and “local†breaking where the wave breaking occurs at lower levels of the vortex and inhibits further wave propagation into the upper levels [Dritschel and Saravanan, 1994; Waugh and Dritschel, 1999; Polvani and Saravanan, 2000]"

Looking at the last couple of years it is my reckoning that the Feb 2009 event was an over the top type and the last two winters have started off with the centrally positioned upward tropospheric wave breaks. It is these that have given the better blocking and better chance of cold. This January I wouldn't be surprised to see an over the top type wave break that leads to a SSW.

Thanks for pursuing that C.

Yes i was thinking of an upwelling when i first saw that on Nov.9th--crikey seems an age ago now.lol.

As we know now it was nothing significant.

Anyway thanks for the explanation.

[sebastiaan1973]

Chionomaniac, so there are two mechanisms for wave breaking into the stratosphere, is one way leading to both

“vortex displacement†or “vortex split†events? Or just one of these two? (specific mechanism for a specific SSW)

thanks!

[chionomaniac]

Which you believe is less conducive to sustained blocking in areas that impact the UK then a vortex split like the last two? (in terms of bringing colder weather)

I know what has been better the last two years. The 'local' breaking waves certainly did produce. I am now left wondering could we have these local wave breakers with a cold stratosphere.

Chionomaniac, so there are two mechanisms for wave breaking into the stratosphere, is one way leading to both

“vortex displacement†or “vortex split†events? Or just one of these two? (specific mechanism for a specific SSW)

thanks!

I suspect that SSW's are a combination of both, but not too sure. I suspect more research needed. The last two winters have seen the local upward wave breakers that caused lower splits from the troposphere up to the middle stratosphere, but did not cause SSW's. These appeared far better in producing HLB's whereas the remote wave breakers need to propagate right down from the upper stratosphere to the troposphere before influencing matters - a far greater distance to produce dramatic tropospheric blocking.

[chionomaniac]

First evidence of a 'remote' wave breaking into the top of the atmosphere. Wave number 2 has increased activity at T+240. Any little disruption to the vortex increasing in strength is welcome at this point.

First signs of a warm wave at 1 hPa

Let' see if this goes anywhere.

[Great Plum]

At that sort of timescale, how reliable is it that that will occur? Is 240hrs considered FI in stratospheric conditions?

[chionomaniac]

At that sort of timescale, how reliable is it that that will occur? Is 240hrs considered FI in stratospheric conditions?

Yes, most definitely, but with the difference that the straotosphere is subject to far less wild fluctuations, due to it being far more stable than the troposphere.

Some more slight warming seen on the GFS 30 hPa forecasts.

Again not brilliant, but I can see this kind of thing happening and reoccurring in early winter.

[georgiedre]

what would all this mean chino? soz but im a learner! thanks

[chionomaniac]

what would all this mean chino? soz but im a learner! thanks

So am I still!! If you go to the first post in the thread then the basics are explained.

[A Winter's Tale]

Has there been any warming in the stratosphere lately? Also, how long after the warming in the stratosphere did the big freezes of the past 2 winters arrived and how large a warming would you need? Thanks.

[chionomaniac]

Has there been any warming in the stratosphere lately? Also, how long after the warming in the stratosphere did the big freezes of the past 2 winters arrived and how large a warming would you need? Thanks.

Basically we are looking at a completely different start to the stratospheric winter when compared to the previous two winters. This winter we are seeing a rapid cooling of the stratosphere which promotes a strong vortex and a positive AO. The previous two winters we have seen a warmer start with local Rossby wave breaking into the stratosphere which promoted a disturbed polar vortex and negative AO.

[A Winter's Tale]

Basically we are looking at a completely different start to the stratospheric winter when compared to the previous two winters. This winter we are seeing a rapid cooling of the stratosphere which promotes a strong vortex and a positive AO. The previous two winters we have seen a warmer start with local Rossby wave breaking into the stratosphere which promoted a disturbed polar vortex and negative AO.

Thanks.

[MattH]

Morning all...

Just a quick post, but i've been reading through some of these more 'advanced' threads for a while and even I have learnt a few additional things myself!. I believe some of these topics are brilliant with some really excellent pieces of information evident. More often than not, these kinds of discussion are often restricted to US weather forums, but breaking away from that and discussing these kinds of scenarios in relation to how they can affect the weather in the UK is again, excellent and no doubt many are learning a lot from what is, to be honest, is a complex area of meteorology and the likes!...

I look forward to reading and perhaps contributing where applicable...

Cheers, Matt.

[gottolovethisweather]

Morning all...

Just a quick post, but i've been reading through some of these more 'advanced' threads for a while and even I have learnt a few additional things myself!. I believe some of these topics are brilliant with some really excellent pieces of information evident. More often than not, these kinds of discussion are often restricted to US weather forums, but breaking away from that and discussing these kinds of scenarios in relation to how they can affect the weather in the UK is again, excellent and no doubt many are learning a lot from what is, to be honest, is a complex area of meteorology and the likes!...

I look forward to reading and perhaps contributing where applicable...

Cheers, Matt.

Here Here.

Welcome aboard the Netweather rollercoaster of emotional turmoil, ie. the forum boards.

Whoops OT, bye!

gottolovethisweather

Edited November 23, 2011 by gottolovethisweather

[chionomaniac]

Morning all...

Just a quick post, but i've been reading through some of these more 'advanced' threads for a while and even I have learnt a few additional things myself!. I believe some of these topics are brilliant with some really excellent pieces of information evident. More often than not, these kinds of discussion are often restricted to US weather forums, but breaking away from that and discussing these kinds of scenarios in relation to how they can affect the weather in the UK is again, excellent and no doubt many are learning a lot from what is, to be honest, is a complex area of meteorology and the likes!...

I look forward to reading and perhaps contributing where applicable...

Cheers, Matt.

Thanks, and please do Matt. Any extra contribution would be extremely welcome.

[MattH]

Thanks, and please do Matt. Any extra contribution would be extremely welcome.

Just one quick question, which you may be able to answer, or find!...I spotted somewhere in one of these threads a link to some of the ECM data including the MJO forecast which was from the NCEP site I think, however I can't find the damn post now for some reason. I was interested to know whether this was the same ECM data which I have access through work, including the EC 32 day information etc.

I look forward to joining in!...

Cheers, Matt.

[chionomaniac]

Just one quick question, which you may be able to answer, or find!...I spotted somewhere in one of these threads a link to some of the ECM data including the MJO forecast which was from the NCEP site I think, however I can't find the damn post now for some reason. I was interested to know whether this was the same ECM data which I have access through work, including the EC 32 day information etc.

I look forward to joining in!...

Cheers, Matt.

This is the best one due to the number of models and ensembles used.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml