Stratosphere Temperature Watch 2012/2013

[Tim Bland]

Brave prediction Ed, my hat goes off to you though. As much as I want to believe we will see a flip to northern blocking I just can't see it ATM. Cards are stacked in favour of a cold winter but it's just not showing on FI charts or CFS. My forecast is for a positive NAO for Dec, start waming in Dec so negative AO from mid Jan onwards

[MattH]

This is just for the record really for future reference and verification, but I have just spotted that the EUROSIP model which I have access to, has been 'added to' for the October update.

This seasonal model did take the ECMWF, Met Office and Meteo-France seasonal models/data into consideration to come up with the usual MSLP anoms and the likes for the coming months. However, I have just noticed that it has also been extended out to 3 months instead of just 2. Not only that an addition has been made and it now, allegedly, takes into consideration to the NCEP. To what extent I don't know at this stage, but this is definitely an addition.

For the record, this October update is signalling a weak signal for higher pressure to the N and NW of the UK with a +ve 500mb height anom, again to the N or NW of the UK through the winter with temperatures -0.5C to -1C below average. This is in conflict with the ECMWF seasonal model with the last update, as I have previously stated, showing a more zonal and 'typical' UK winter pattern which is essentially +NAO.

Be interesting to follow this up with the November update in due course...

M.

[MattH]

I wonder if the 12Z GFS Control run is on to something beyond the 22nd? haha

http://pbs.twimg.com/media/A7HtcpnCYAAJuBX.png:large

M.

[Gael_Force]

Yes, the CFS is now included in the European suite. MF have regular monthly updates (Nov just issued) - a cold set for coming winter. First column is for mainland France.

http://france.meteofrance.com/content/2012/10/27276-48.pdf

[chionomaniac]

Matt, is it possible that you could post in the model thread for the crossover info- I am sure your very relevant views would be most welcome and appreciated there (and with a wider audience too)!!

[FrenchScotPilot1]

Hi Stephane and welcome.

I have always though it has been a mixture of adiabatic compression, diabatic transfer of heat from outside the polar vortex - through the surf zone, frictional heat and influx of ozone.

Surely during summer the waves dont enter because the thermal difference isn't strong enough to create Rossby waves strong enough to deflect that far?

Thanks chionomaniac, it sounds it little more complicated than what I thought but what else to expect. As for the summer set up, it makes perfect sense.

If you guys need me to translate from french sites, it will be with great pleasure, I may as well be useful

Stephane

[BLAST FROM THE PAST]

I'm fascinated and rather surprised by MetO extended outlook and would be v nice for it to be right [and could well be]. I'm strongly in favour of Dec being in 6.5c range coming off the back of a mild to very mild latter 3rd Nov. One only though has to look at Dec 1985 for example that it doesn't mean the month is written off as there'll be some big ups and downs...just that I'm suggesting it won't be a Dec 81 or 2010. I think the low solar state and -ve PDO is driving the pattern against being full on zonal despite the cooling stratos.

BFTP

Edited November 7, 2012 by BLAST FROM THE PAST

[lorenzo]

C posted around the MJO phases in yesterday model thread, UKME run quite different from the ECM / GFS solutions. Wonder if this is where the signal is from for the extended range?

Good to see you off the fence too C, going to be a good watch what unfolds, a mini battle of the gurus if you like, between the AO forecast in GP thoughts.

I think the last couple of days have seen some added stress in model viewing where folks are looking for a 2010 again. Using that once in 100 yr cold spell as a template is ultimately going to lead to some disappointment.

Would love a Wave 2 and subsequent Vortex split to come off - but patience is the thing here..

Edited November 7, 2012 by lorenzo

[Alan Robinson]

Hi Stephane and welcome.

I have always though it has been a mixture of adiabatic compression, diabatic transfer of heat from outside the polar vortex - through the surf zone, frictional heat and influx of ozone.

Surely during summer the waves dont enter because the thermal difference isn't strong enough to create Rossby waves strong enough to deflect that far?

What have adiabatic processes to do with any of this? Why should the increasing heat of a descending and compressing parcel of air not dissipate into cooler surroundings?

[bluearmy]

Whilst the zonal wind forecast looks similar to yesterday, its interesting that beyond week 1 the direction of propagation is definitely towards 50/60n rather than the polar regions as per recent output.

[chionomaniac]

What have adiabatic processes to do with any of this? Why should the increasing heat of a descending and compressing parcel of air not dissipate into cooler surroundings?

Thanks for your polite questions Alan.

I am no expert in advanced physics, but whatever does cause the heating does dissipate into the cooler surroundings - the rest of the vortex - and it is this that causes the vortex weakening and in the case SSW's, complete breakdown.

[Tom Quintavalle]

I've noticed over the last few days that GFS forecast models out beyond 10-14 days, (albeit low resolution part of the run), are showing the PV fragmenting and weakening after being more organised and strengthening, up to that point. Also the PV shifts from Arctic Canada/W.Greenland to N.Siberia.

http://cdn.nwstatic....192/npsh500.png

http://cdn.nwstatic....240/npsh500.png

http://cdn.nwstatic....300/npsh500.png

http://cdn.nwstatic....324/npsh500.png

http://cdn.nwstatic....npsh500.192.png

http://cdn.nwstatic....npsh500.240.png

Is this the signal that the ECM longer range model is picking up regarding HLB in late Nov/early Dec? Like the GFS model, ECM show a strengthening vortex out to the end of the run that we see, i.e up to 240 hours.

Interesting times ahead and eagerly awaiting Matt's update today.

Regards,

Tom.

Edited November 8, 2012 by TomSE20

[Alan Robinson]

Thanks for your polite questions Alan.

I am no expert in advanced physics, but whatever does cause the heating does dissipate into the cooler surroundings - the rest of the vortex - and it is this that causes the vortex weakening and in the case SSW's, complete breakdown.

Thanks for that reply.

I'd hardly call adiabatic processes "advanced" physics, it simply means there is no heat transfer going on, which is of course a simplification to help us model reality; and though fluid dynamics can become very intricate, I should have thought that whatever goes on concerning the polar vortex could be explained to some satisfaction with our present understanding of nature. The problem - in my opinion - is twofold; there are so many factors involved, making the business very complex, and moreover, the stratosphere is a very difficult spot to carry out research, with the polar stratosphere even more disadvantageous than the temperate or tropical latitudes.

[chionomaniac]

Thanks for that reply.

I'd hardly call adiabatic processes "advanced" physics, it simply means there is no heat transfer going on, which is of course a simplification to help us model reality; and though fluid dynamics can become very intricate, I should have thought that whatever goes on concerning the polar vortex could be explained to some satisfaction with our present understanding of nature. The problem - in my opinion - is twofold; there are so many factors involved, making the business very complex, and moreover, the stratosphere is a very difficult spot to carry out research, with the polar stratosphere even more disadvantageous than the temperate or tropical latitudes.

For those who perhaps have studied physics, I am sure that adiabatic and diabatic processes are not complex at all, but I do confess that even with a physics A level to my name, ( a good few years ago mind you!), I did have to relook up the phrases when I joined NW. And I am sure that there are many more in my situation reading this thread!

I believe that the rest of your post is absolutely right, but there are a number of scientists studying the physics of the middle atmosphere an eventually they will be able to shed further light on the processes.

Back to the forecasts and there is little change today. No evidence of that Canadian Warming forecast either - just the slow cooling and vortex increasing in the mid stratosphere and that this will eventually (probably) filter down to the lower stratosphere unless we see tropospheric wave breaking into the lower strat.

For those wondering about my 60/40 forecast for a +ve AO for the start of December, this still remains. However, the Metoffice updates, ECM 32 dayer that suggest Northern blocking alongside GP's thoughts, will prevent this changing for the worse presently - so I would suggest that a 40% chance of a negative AO with the current strat cooling should be grabbed at!

Edited November 8, 2012 by chionomaniac

[Rocheydub]

For those wondering about my 60/40 forecast for a +ve AO for the start of December, this still remains. However, the Metoffice updates, ECM 32 dayer that suggest Northern blocking alongside GP's thoughts, will prevent this changing for the worse presently - so I would suggest that a 40% chance of a negative AO with the current strat cooling should be grabbed at!

Great post C

Especially this last bit. A little like Neil Lennon the Celtic manager last night when asked before the Barcelona game...

Reporter "Neil, Barcelona will probably dominate the ball possession, what will you do"

NL " yes, they'll have probably 70% possession, it's what we do with our 30% that counts though!!"

Slightly off topic (to say the least) but I felt it was a good analogy!

[TobyT]

"For those who perhaps have studied physics, I am sure that adiabatic and diabatic processes are not complex at all, but I do confess that even with a physics A level to my name, ( a good few years ago mind you!), I did have to relook up the phrases when I joined NW. And I am sure that there are many more in my situation reading this thread!"

Thanks for you update on the strat Chio, as always your posts are concise and easy to follow especially for a novice like myself.

I would not have a clue about adiabatic and diabatic processes and like you say I am sure their are many others on here who would be unfamiliar with these terms.Sorry if Im a bit off topic but felt it needed to be said.

Edited November 8, 2012 by TobyT

[Vertical Limit]

Fascinating stuff at present for what lies ahead at the end of the month and into the start of winter! What seems perplexing to me though (I'm a complete novice so probably completely wrong) is the latest couple of GFS runs are signalling a negative AO/NAO pattern, although in deep FL, the ECM32 day and Met Office suggest something similar. So what drivers are they seeing to suggest a blocked pattern when on the other hand, the upper/mid strat is cooling as 'normal', with no sign of any warming and if this cooling continues to progress unhindered into the lower strat then this would suggest an eventual positive AO outcome. GP's preliminary winter thoughts presentation highlights that there are potentially a lot of 'strong' signals and drivers pointing towards a negative AO winter. Could it be that the the Strat is going to be knocked out by a combination of punches or will it play rope a dope and wait until the 12th round for its knockout.

If this has been covered before then my apologies for repeating it all again.

[snowking]

Interesting wave 1 and 2 activity showing up on the berlin site:

If we start with wave 1

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta1_a12.gif

This wave forecast to downwell towards 20mB:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta1_f72.gif

Meanwhile wave 2:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta2_a12.gif

Which starts to upwell at day 8:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta2_f192.gif

And continues to day 10:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ta2_f240.gif

Whilst the wave 2 activity is out towards the end of the forecast period (ie FI) the wave 1 downwelling much closer to occurring. So at least a little pressure being placed on the stratosphere from both ends

SK

[feb1991blizzard]

I appologise in advance if this has been covered recently but are we more likely to get a downwelling or an upwelling, and also, as i understand it, every warming event and subsequent slowing / reversal of zonal winds at every level is good news, or is that too simplistic a comment.

Edited November 8, 2012 by feb1991blizzard

[The watcher]

Hi there Vertical limit. I'm inclined to think that although the strat is cooling as average, it is the Polar Vortex that matters, we continue to see it quite disorganised which is why blocking at higher latitudes is still being produced in model output. That is why the Ao and Nao are still neupral to negative, they are the reflection of the pattern at hand and possibilities into the future.

Fascinating stuff at present for what lies ahead at the end of the month and into the start of winter! What seems perplexing to me though (I'm a complete novice so probably completely wrong) is the latest couple of GFS runs are signalling a negative AO/NAO pattern, although in deep FL, the ECM32 day and Met Office suggest something similar. So what drivers are they seeing to suggest a blocked pattern when on the other hand, the upper/mid strat is cooling as 'normal', with no sign of any warming and if this cooling continues to progress unhindered into the lower strat then this would suggest an eventual positive AO outcome. GP's preliminary winter thoughts presentation highlights that there are potentially a lot of 'strong' signals and drivers pointing towards a negative AO winter. Could it be that the the Strat is going to be knocked out by a combination of punches or will it play rope a dope and wait until the 12th round for its knockout.

If this has been covered before then my apologies for repeating it all again.

[Polar Maritime]

Patiently waiting for Matt Hugo's take on the ECM32 update......

[Radiating Dendrite]

Patiently waiting for Matt Hugo's take on the ECM32 update......

According to Twitter it is still going for cold and blocked at the end of the month!

[bluearmy]

According to Twitter it is still going for cold and blocked at the end of the month!

But the seasonal is not for a cold winter

[Methuselah]

But the seasonal is not for a cold winter

Have any seasonals ever been right?

[Don]

But the seasonal is not for a cold winter

The seasonal has updated then?