Stratosphere Temperature Watch 2015/2016

[Nouska]

2 hours ago, Cloud 10 said:

No doubt been posted before,but seems to be quite pertinent as we head for some sort of meaningful warming of the stratosphere.

http://birner.atmos.colostate.edu/papers/Butleretal_BAMS2014_submit.pdf

 

 

 

I see Hannah Attard is using 10 hPa and 65N for her charts and graphs. Am I missing a reason why not the accepted 60N?

http://www.atmos.albany.edu/student/hattard/realtime.php

 

[MJO]

Hi- yes there is a sign for SSW but there is no sign for negative AO (I mean a really negative ssw AO values). For example the EC Ensembles are expecting that the AO will go up again after a negative values for a short time ! 

[Dennis]

Its nice to follow - lets see what the results will be

[phil nw.]

1 hour ago, MJO said:

Hi- yes there is a sign for SSW but there is no sign for negative AO (I mean a really negative ssw AO values). For example the EC Ensembles are expecting that the AO will go up again after a negative values for a short time ! 

Yes it sound's like vortex resituating more centrally after it,s current displacement. 

[Chris1986]

1 hour ago, MJO said:

Hi- yes there is a sign for SSW but there is no sign for negative AO (I mean a really negative ssw AO values). For example the EC Ensembles are expecting that the AO will go up again after a negative values for a short time ! 

The idea of a reversal is certainly being flirted with. Apologies for the experimentals I can't get decent 10hpa wind charts.

[fergieweather]

4 hours ago, bluearmy said:

Poor estimate of the strength of the flow by me!

the zonal winds on that ECM run are strange indeed. Pretty quiet a early on and then ramping up somewhat days 6/7 before falling back quiet again by day 10. Presumably this is due to the vortex attempting to stay close to the pole as it feels the pressure from the higher heights pushing it off.  Will it recover and bring the zonal flow back up again or is it beaten into being displaced this side of the NH? 

 

GloSea5 strat diagnostics continue to be more supportive of a resumption of the zonal flow circa mid-month BUT this may not prove a protracted phase... however,(tropospherically) it also returns westerly mobility as the preferred broadscale pattern through later Feb.

Edited January 31, 2016 by fergieweather

[bluearmy]

2 hours ago, MJO said:

Hi- yes there is a sign for SSW but there is no sign for negative AO (I mean a really negative ssw AO values). For example the EC Ensembles are expecting that the AO will go up again after a negative values for a short time ! 

Actually, the ECM eps mean AO goes negative around the 8th, dropping  quickly to -2 before recovering towards neutral by end week 2. NAO a couple days behind.  GEFS/GEM ens are fairly neutral throughout.  I wouldn't be assuming too much re the AO at the moment. Have been done crazy neg controls recently. 

[Rocheydub]

2 hours ago, phil nw. said:

 vortex resituating . 

Sorry to ask, but can you explain what this is?

[bluearmy]

14 minutes ago, Rocheydub said:

Sorry to ask, but can you explain what this is?

It just means returning

[Rocheydub]

35 minutes ago, bluearmy said:

It just means returning

 

Oh, I see now 're-situating'!! I thought it was a form of the word residual!!! Thanks for explaining what should have been plainly obvious!!!

[Cloud 10]

5 hours ago, Nouska said:

I see Hannah Attard is using 10 hPa and 65N for her charts and graphs. Am I missing a reason why not the accepted 60N?

http://www.atmos.albany.edu/student/hattard/realtime.php

 

 

I suppose thats the problem with moving the goal posts on what is or what's not an official SSW.

 

Hopefully it will be left at 60N 10 HPA.

[chris55]

3 hours ago, fergieweather said:

GloSea5 strat diagnostics continue to be more supportive of a resumption of the zonal flow circa mid-month BUT this may not prove a protracted phase... however,(tropospherically) it also returns westerly mobility as the preferred broadscale pattern through later Feb.

So Glosea5 seems to be backing nothing of interest when it comes to a colder Feb (ie, some sustained northerlies or easterlies). A mobile westerly flow from the Met offices best "strat including" model.

Most signs of late are not really pointing to anything special in the last 30 days of winter.

We are going to need a big dollop of luck to squeeze something properly cold out of this winter. Not impossible by any means but something needs to give lol.

 

[Banbury]

33 minutes ago, chris55 said:

So Glosea5 seems to be backing nothing of interest when it comes to a colder Feb (ie, some sustained northerlies or easterlies). A mobile westerly flow from the Met offices best "strat including" model.

Most signs of late are not really pointing to anything special in the last 30 days of winter.

We are going to need a big dollop of luck to squeeze something properly cold out of this winter. Not impossible by any means but something needs to give lol.

 

Its not looking great , I think most ( me included) were hoping for a colder end to Winter with the help of a SW

[Duane S.]

I'm struggling to understand the dispondancy in here. Putting aside the fact we are now fairly well into the 2nd half of winter official and there is nothing anybody can do about that, the potential heading into Feb is there for all to see, isn't it?

The fact that the latest ECM u wind forecast came in at +16 m/s instead of the hoped for reversal at D10 isn't really telling the whole story. The reversal of winds is forecast to make it down to 5mb at 60N + right across from about 72 N to 90N @ 10mb. That tells me it would only take either a relatively small adjustment to change that forecast chart into one that shows an official SSW or that one MAY be just around the corner.

But... even if it does only end up being a 'minor warming' I am convinced that if these 10mb temp and epv charts come to fruition (and that looks increasingly likely)...

.

... High Level Blocking will be in abundance come mid month and it would then be a case of hoping it sets up in our favour.

[Recretos]

Well. Not sure where to begin. A lot has been said in the last few pages. And the reason I was absent was not because I wouldn't have time, but because there was nothing for me to write about, what I haven't already said. 

On 22. 1. 2016 at 10:51 PM, Recretos said:

This warming is very undefined as such, and the only response as I have shown in 3D in the first phase is the Alaskan ridge formation. Do not also forget about the unusually strong Azore/African ridge area.

And lets keep the strat splits out of the discussion since there is wave1 domination atm, and first deal with the displacement.

And I am not a pesimist, but a cautius realist. We are not dealing with a major SSW, like the 09 one or 2013. A major SSW is not even forecasted yet, except ocasionally by some individual GEFS perturbations. 
We are dealing with a minor SSW until further notice, and so the rules of the game are different. Things could go in Europe's favour, but sweat and tears are needed for that. So lets not jump the wagon, shall we...

Just a friendly reminder.

 

And what happened was, everybody or almost everybody did actually jump the SSW wagon (not a gun, for which people actually mocked me for) and drove off into the unknown, expecting to arrive to a new land, abundant with snow and cold. Well, its time that we do a reality check and see just how far this wagon has actually got. 

 

On 22. 1. 2016 at 1:01 PM, Recretos said:

Here is my latest animation, from 00z GFS showing geopotential height layers in 3D. Top down are 10mb, 30mb, 70mb, 250mb and 600mb. You can see the upward induced split, the effect of the Azores high, reaching into lower strat, and the downward propagating wave from the strat wave 1, creating the Alaska ridge in the process. 

 

 

GEFS also sees the connection of the strong wave 1 with the troposphere, so here we have our fast coupling response. The Alaskan ridge is not all strat induced, but is greatly helped by the strat wave, makin more room for the ridge. 

     

10 days, 240h later, we are exactly where we are supposed to be as predicted. With a minor wave1 displacement SSW. Despite all the hype, in the current phases what it will actually do, is displace the cyclonic energy, dropping it into the north Atlantic/Canadian sector, and the wave 1 anti-vortex will help to promote Alaskan ridge building.

 

 

Great imagery from weatherbell, by Ryan Maue, and a good example how to properly use anomalies in stratospheric forecasting.

   

And my share.

 

Looking at the NASA model, here is the 120h 5-day change of the zonal mean-zonal wind. We can see the reduction of the zonal components from 60N to 90N. Yet at the same time, we can see the slight increase of tropospheric zonal components, mainly to do with the fact that the displacement that causes the reduction of the stratospheric zonal winds also causes not only the energy to build the Alaskan ridge, but also to support the cyclonic energy in the Canadian/Atlantic sector. That is more profound after 240h, when the polar vortex tries to sustain/recover its angular momentum. That can sometimes be quite a bursty process, and in our case it actually is enough burst to have a fast trop response and the connection between upper and lower core is established briefly, enough for some energy to transfer besides the general one, and kinda mixing the charts for us even more. And what the wave 1 actually manages to do, is as it grinds along the vortex, it actually creates a brief cross-polar flow and helping to further spin-out the south lobe of the vortex, helping it to recover down the line, and sending the cyclonic energy down into the trop as it intensifies and the pressure drops. Much like you see above on the GEFS charts. the reach of the polar anticyclone is not really that far down reaching, and is weaker than the trop response to the re-spin of the vortex core, and sending a cold trough into North America. On its eastern flank downwind, the ridge could briefly build in north Atlantic, but I do not believe it would be any long-lasting ridge, since its will be later under the affect of the upper core transfer. 

  

What else to say. I was trying to be the voice of reason, to prevent euphoria due to misunderstanding of the strat dynamics, and to explain just how each event is different than others, and must be taken with an analytical approach across multiple layers and multiple parameters. For some time I was trying to emphasise just how important the height fields are. The event might be called stratospheric warming, but temperature on its own is not even nearly enough for anything significant. The actual effects and to track them, we must focus on the height fields. That is why the zonal mean zonal wind is also so important because is directly related to the geopotential height field via geostrophicy. 

What we can all learn from this event, is that we need to learn more. All of us. And no, I do not have a Phd in meteorology. Not even close. I have finished agricultural high-school, so I am a farmer officially. I had physics for 2 years in elementary school. But I tend to put a lot of focus into what I do. Anything. Especially if it is something I am passionate about, like meteorology. So bottom line, I am just an amateur/enthusiast like 95% of people on this great forum. So I am not necessarily correct in everything I state in this post or any other. just a disclaimer  (not even some pro's are). 
But what I am trying to say is that you can learn new stuff and you can learn about stratospheric dynamics, even without heavy physics background. Just think logically, since physics are 95% of logic. it just needs to be explained in the correct matter. heavy scientists usually like to over-complicate it with 10-miles long equations and technical terms that make your tongue split in half like a wave 2 major SSW.  

Finishing off with another animation to help explain dynamics, from 10mb to 150mb. it shows vorticity. You can see how big of a dent the wave1 leaves in the vortex core, but its not very down reaching. The later spin-off of the polar vortex as the wave 1 grinds along it, has a stronger effect. based on all the graphics and animations and everything you can imagine, I would suggest that there is a buffer zone somewhere along the 70mb, and down, through which the minor SSW effects are not translated very well. The cyclonic energy on the other hand is stronger so it has no big problems penetrating down. 

 

best regards

Edited February 1, 2016 by Recretos

[Methuselah]

Great post, Recretos. Your use of graphics has really helped me understand what words alone have not. If a picture saves a thousand words, your graphics save a million!

[Singularity]

The 'stratosphere playing ball' was always a major caveat to the winter outlooks. 

For me, the level of hope peaked in mid-Jan, when the models were showing a displacement of the vortex toward Eurasia and there was little sign of the stronger displacement back the other way that has since materialised. Back then, it was possible to visualise how such a displacement, if maintained for long enough, could team up with emerging tropical forcing late Jan (at least that aspect has materialised) to get a good mid-Atlantic ridge and Euro trough combination for early-mid Feb.

So the hope was that this first bout of warming would be upgraded enough to do the job... but then along came this second, stronger warming event which looked from an early stage like it could achieve 'minor SSW' status, with a major event not out of the question but certainly an outside chance. At that point I was thinking 'this needs to upgrade to become a major SSW, else we're in trouble'. 

Now we have arrived at a point where we see GFS predicting a minor SSW with a displacement which favours an Alaskan ridge. Perhaps MJO forcing will modify this enough to sharpen up the trop. pattern to the point that we get a decent mid-Atlantic ridge for a time mid-month, but this is making the most of a bad situation.

By mid-month it does appear that the vortex will be considerably less cold at 10 hPa but still packing a punch at 30 hPa. Does solar input to the upper levels begin to rise markedly by around mid-Feb? 

 

 

The vortex has been extraordinarily strong this season, which is not a typical manifestation of an El Nino winter but may in fact be related to climate change - I'm sure I've come across the odd comment about the stratosphere cooling as the troposphere warms?

It makes me wonder how much we can rely on the seasonal weakening of the vortex to allow tropical forcing to do its job late in the month and produce extensive high latitude blocking close to our NW in particular. I notice in the MOD thread that Fergie has finally mentioned an MJO-related colder signal with respect to Met Office discussions, albeit only as a possibility and not one that they have enough confidence in to alter forecasts toward just yet. 

Of course by that stage in the year, the setup has got to be truly exceptional to deliver lying snow down here. Even March 2013 didn't cut it! So I'm looking rather desperately toward getting something from the mid-Atlantic ridge possibilities mid-Feb. The tropics versus the stratosphere, the former in with a chance of winning a battle but the latter almost definitely winning the war.

[knocker]

1 hour ago, Singularity said:

The vortex has been extraordinarily strong this season, which is not a typical manifestation of an El Nino winter but may in fact be related to climate change - I'm sure I've come across the odd comment about the stratosphere cooling as the troposphere warms?

 

The odd comment? That's quite strange way of putting it.

Greenhouse gases (CO2, O3, CFC) generally absorb and emit in the infrared heat radiation at a certain wavelength. If this absorption is very strong as the 15µm (= 667 cm-1) absorption band of carbon dioxide (CO2), the greenhouse gas can block most of the outgoing infrared radiation already close to the Earth surface. Nearly no radiation from the surface can, therefore, reach the carbon dioxide residing in the upper troposphere or lower stratosphere. On the other hand, carbon dioxide emits heat radiation to space. In the stratosphere this emission becomes larger than the energy received from below by absorption. In total, carbon dioxide in the lower stratosphere and upper troposphere looses energy to space: It cools these regions of the atmosphere. Other greenhouse gases, such as ozone (as we saw) and chlorofluorocarbons (CFC), have a weaker impact, because their absorption in the troposphere is smaller. They do not entirely block the radiation from the ground in their wavelength regimes and can still absorb energy in the stratosphere and heat this region of the atmosphere.

Or in slightly more detail

Stratospheric Cooling and Tropospheric Warming - Revised

http://www.skepticalscience.com/Stratospheric_Cooling.html

 

Edited February 1, 2016 by knocker

[Evening thunder]

4 hours ago, Singularity said:

Of course by that stage in the year, the setup has got to be truly exceptional to deliver lying snow down here. Even March 2013 didn't cut it! So I'm looking rather desperately toward getting something from the mid-Atlantic ridge possibilities mid-Feb. The tropics versus the stratosphere, the former in with a chance of winning a battle but the latter almost definitely winning the war.

I think the south was unlucky in March 2013 - the Channel Islands got clobbered by a blizzard. I remember April 2008 giving quite a covering to parts of the south such as Eastbourne, and there was a snow event slightly east of here in March 2009.

Edited February 1, 2016 by Evening thunder

[Singularity]

@knocker

Thank you for your informative response. By 'odd comment' I meant as in 'a few here and there', also implying that I had not yet read into that particular topic.

You have essentially saved me the search, and confirmed my suspicions. An aspect of climate change that threatens to produce stormier winters for the UK overall, and could lead to some mighty clashes with the blocking features promoted by forcing such as SAI in years where there is a good amount of work being done to keep the vortex weaker and more variable.

Perhaps it won't be too many years before we see what happens when a strong (but not ferocious as per this winter) vortex is taken down by a powerful wave-2 attack. Like 2009, when the zonal wind hit 80 m/s at 1hPa prior to the dramatic decline:

Those were the days 

[Singularity]

1 hour ago, Evening thunder said:

I think the south was unlucky in March 2013 - the Channel Islands got clobbered by a blizzard. I remember April 2008 giving quite a covering to parts of the south such as Eastbourne, and there was a snow event slightly east of here in March 2009.

True, I forget about that, probably out of preference as it got right on my nerves at the time -  there had been some runs which pasted my back yard and then came the infamous correction southward!

Looking at the archives I can really see what you mean by unlucky:

  

That's a shortwave that could have affected CS England but instead just grazed the SE, then the Channel Islands Blizzard, then a LP dropping down about 200 miles too far west. I do remember taking a break from the models out of frustration.

Sorry to wander off topic mods - though I have a feeling the above will prove rather relevant for the final days of Feb and into March this year. Interesting that the above took until 8 or 9 days to kick off, and actually had a pretty warm day on the 4th or 5th, with maximums in the high teens in the south.

Incidentally, does anyone know what the MJO was up to in March of that year? TIA

[nick sussex]

Singularity you can see past MJO's here right back to 1975:

http://www.bom.gov.au/climate/mjo/

In terms of March 2013:

 

Edited February 1, 2016 by nick sussex

[Allseasons-Si]

I had my doubt's the other day as this spike was trending down again but...

there she goes again,i will look tomorrow to see if this progresses

30hpa10hpa

@Recretos,nice post and animation there again thankyou

 

[Singularity]

3 hours ago, nick sussex said:

Singularity you can see past MJO's here right back to 1975:

http://www.bom.gov.au/climate/mjo/

In terms of March 2013:

 

That's fantastic, thanks for the link Nick 

The central Pacific convection correlates well to blocking just as it does in Feb, though not as extreme.

 

Indeed you can see the support for a more settled regime as you head towards the middle of the month.

[Eastwoods]

I know it probably doesn't add to the discussion but some interesting pictures of nacreous clouds on the BBC website as seen from northern Britain today sorry unable to put up link but good call from vorticity0123 a few days ago http://www.bbc.co.uk/news/in-pictures-35462395

Edited February 1, 2016 by Eastwoods
Added link???