Stratosphere Temperature Watch 2011/2012

[Weather-history]

It would be interesting to see the temperature profile of the stratosphere during the run up to January 1984. That was highly active zonally with what looks an intense vortex but there was plenty of wintry weather. Was it a very cold stratosphere?

[chionomaniac]

It would be interesting to see the temperature profile of the stratosphere during the run up to January 1984. That was highly active zonally with what looks an intense vortex but there was plenty of wintry weather. Was it a very cold stratosphere?

A really weird one to figure out. Intermittent warming and cooling episodes, possible upwelling waves, upper negative zonal wind anomalies with positive lower wind anomalies.

It is the type of scenario that we would benefit if we had access to the upper vortex charts from that period.

[summer blizzard]

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_1983_merra.pdf

Looks fairly close to average overall until late January when we had record cold followed by the biggest stratospheric warming on record.

[BLAST FROM THE PAST]

name='chionomaniac' timestamp='1322581736' post='2167490']

It is hardly a cold set up that we are in now.

http://forum.netweat...s/page__st__420

I think the models will show different timings and different ways of northern blocking setting in for some time yet but eventually I think the switch to very cold conditions will appear and set in late Nov. A repeat of 2010 looks likely, question yet to be resolved IMO is will it dig in. I like this pattern we have currently for down the line events. What is showing in the models are tentative signs of retrogression, tentative for now.

BFTP

Exactly, models will toy with the idea for a while yet and a retreat/stalemate shown by ECM is precisely what I'm on about, no change for a while. It won't IMO be until late Nov for the switch. Now bearing no resemblance who said anything about the synoptics being like last year? What we may well see is a switch from the mild conditions to very cold fairly quickly when it happens and my timing is late Nov [last ten days say]. I think models are tentatively showing [too early] what may be the way forward down the line. Its not a bold statement, just what looks the way forward on my forecast method at this early stage.

BFTP

end BFTP quote.

These are not the only examples, Fred, but a few that I came across. Please don't suggest that I have misquoted you.

Sadly, the fact is that I believe you with regarding that the jet stream will have a southwards tendency - but that this point that you put across can get lost in the endless promise of cold.

c

Yep C, see where you come from re the 2010 bit and that is contentious and the switch of pattern is flatter for sure though it is caveated and never promised eg big question will it dig in? BUT it does show that I thought it may happen when the pattern switched. The rest seems fine with each whole post rather than highlighted snippets...but absolute clarity is needed in posts for sure. No promises and no mid Nov etc, timing re pattern change is ok and plenty of subsequent posts adjusting that.

Ok I will be as clear and as unambiguous as possible from now on and I will avoid answering questions that may need me to repeat -ve PDO, perturbation cycle etc. It clearly irks you but it wasn't making a point but answering a question? Surely folk are allowed to do that? But to avoid further stuff like this I won't.

Just for record going forward the pattern is not going to dig in 'very cold' for Dec and if any real cold shot of the month is to occur then maybe timed for 3rd week IF it happens at all. I don't see the Euro HP or Bartlett being a major player at all from now on either.

No promise of cold, just an increase in likelihood due to factors mentioned.

Hope we can move on from here. Again no LRF from me just updates of thoughts

BFTP

Edited November 29, 2011 by BLAST FROM THE PAST

[cooling climate]

Its ok saying that BFTP, but you said this last year, that the winter would be good. Yes December was good, sorry outstanding, the rest of winter was crap. No storms at least or anything noteworthy. You don't back up your reasons to say why you think it will be fascinating and it would be welcomed to know why, considering you are a good poster and have a lot of knowledge. Thanks

Agree with this post apart from last sentence, and as CH as pointed

out it is so easy to go back through the threads to weed out the lies

especially when he points to another poster and accuses them mis

- quoting him or lying.

Back on topic.Back in September I made a glaringly big mistake

in thinking that a big blocking signature would again be prevelent end

of November and December. How wrong can you be. Again I could be

wrong but I think this did not materialise due to the + QBO still present

and low Ozone. My cold winter forcast (new year onwards is based around

the -QBO becoming more established throughout the Stratosphere and

also a weaker La Nina than last year with more of a punch from the MJO.

[Gavin P]

Good grief, poor Blast. This thread is turning into a character assasination of the poor chap.

[chionomaniac]

Yep C, see where you come from re the 2010 bit and that is contentious and the switch of pattern is flatter for sure though it is caveated and never promised eg big question will it dig in? BUT it does show that I thought it may happen when the pattern switched. The rest seems fine with each whole post rather than highlighted snippets...but absolute clarity is needed in posts for sure. No promises and no mid Nov etc, timing re pattern change is ok and plenty of subsequent posts adjusting that.

Ok I will be as clear and as unambiguous as possible from now on and I will avoid answering questions that may need me to repeat -ve PDO, perturbation cycle etc. It clearly irks you but it wasn't making a point but answering a question? Surely folk are allowed to do that? But to avoid further stuff like this I won't.

Just for record going forward the pattern is not going to dig in 'very cold' for Dec and if any real cold shot of the month is to occur then maybe timed for 3rd week IF it happens at all. I don't see the Euro HP or Bartlett being a major player at all from now on either.

No promise of cold, just an increase in likelihood due to factors mentioned.

Hope we can move on from here. Again no LRF from me just updates of thoughts

BFTP

Line drawn!

Let's move on.

[BLAST FROM THE PAST]

Agree with this post apart from last sentence, and as CH as pointed

out it is so easy to go back through the threads to weed out the lies

especially when he points to another poster and accuses them mis

- quoting him or lying.

Back on topic.Back in September I made a glaringly big mistake

in thinking that a big blocking signature would again be prevelent end

of November and December. How wrong can you be. Again I could be

wrong but I think this did not materialise due to the + QBO still present

and low Ozone. My cold winter forcast (new year onwards is based around

the -QBO becoming more established throughout the Stratosphere and

also a weaker La Nina than last year with more of a punch from the MJO.

Easy tiger, Ed will agree I didn't accuse him of that. otherwise not a bad post. We all move on and we await news of a warming event or a recovery from the real low temps up above.

BFTP

Good grief, poor Blast. This thread is turning into a character assasination of the poor chap.

No problem,

PMs, I accept responsibilty, we are back on track

BFTP

Edited November 29, 2011 by BLAST FROM THE PAST

[BLAST FROM THE PAST]

Jan 87. That is my favoured analog with QBO, sunspots, cold preceding strat, but not la nina!

C

So was there no SSW to precede or influence the great Jan 1987 event?

BFTP

Edited November 30, 2011 by BLAST FROM THE PAST

[UV-RAY]

C

So was there no SSW to precede or influence the great Jan 1987 event?

BFTP

Indeed there wasn't, I personally feel that far too much weight is given to stratospheric warming events. As 87 shows we can get very cold spells without such warming.

[Gavin P]

Indeed there wasn't, I personally feel that far too much weight is given to stratospheric warming events. As 87 shows we can get very cold spells without such warming.

My sort of crude rule of thumb is that SWW's are needed to get arctic/Greenland blocking. Scandinavian blocking is more about the jet stream and the relative strength and position of the Siberian High.

Of course an SSW would also help to get a Scandinavian High going, but its perfectly possible to achieve a Beast From The East without one.

Edited November 30, 2011 by Gavin P

[phil nw.]

My sort of crude rule of thumb is that SWW's are needed to get arctic/Greenland blocking. Scandinavian blocking is more about the jet stream and the relative strength and position of the Siberian High.

Of course an SSW would also help to get a Scandinavian High going, but its perfectly possible to achieve a Beast From The East without one.

Yes i agree with that Gavin.

In an Easterly pattern with a strong vortex we would do better when the core of the Vortex goes west towards Canada in tandem an extension of the Siberian High--a rare beast in recent times though.

[BLAST FROM THE PAST]

Indeed there wasn't, I personally feel that far too much weight is given to stratospheric warming events. As 87 shows we can get very cold spells without such warming.

Thanks, that will help explain how after the main thrust it died away without resetting. It probably supports the train of thought that a GHP is better for cold longevity than a Scandi Block? Interesting comment re its more about the jetstream

BFTP

Edited November 30, 2011 by BLAST FROM THE PAST

[Isolated Frost]

How cold can the stratosphere get and what are the record lows? I ask this as stratospheric temperatures look well on their way to be at -90c by chrimbo.

[TEITS]

Indeed there wasn't, I personally feel that far too much weight is given to stratospheric warming events. As 87 shows we can get very cold spells without such warming.

The Jan 87 E,ly was a very rare set up because a segment of the PV was sat underneath the Arctic HP that was moving S. This is why the upper temps were as low as -20C in the SE!

I will add if you revisit the Nov 2010 Stratosphere thread you will note nobody predicted the extreme cold that was coming in late Nov/Dec even when it was only a couple of weeks away. Only the Met O knew what was coming!

[chionomaniac]

C

So was there no SSW to precede or influence the great Jan 1987 event?

BFTP

Indeed there wasn't, I personally feel that far too much weight is given to stratospheric warming events. As 87 shows we can get very cold spells without such warming.

Without having access to stratospheric vortex analysis charts for the preceding period it is very difficult to comment. However, the stratosphere at the start of December in 1987 at 30hPa was almost 10ºC warmer than it is presently. Wave number 1 activity was enhanced during the lead up to the cold spell and in fact it was the increased amplitude and repeated peaking of this wave that both led to the cold spell and subsequent SSW.

When looking at a SSW we need to analyse the period before and after the SSW due to the tropospheric/ stratospheric interactions that take place. It is a little bit disingenious to suggest that it is not linked - it is all linked together - but very complex.

So if we get a severe cold spell prior to a SSW it does not mean that there is no linkage, the warmer preceding December stratospheric spell, the increased wave number 1 activity, the drop in mean zonal winds, the evolution of the Scandinavian high all suggest that this is so.

One thing that is most certain is that the likelihood of blocking from the present almost record cold stratosphere is extremely unlikely and if it does occur it is highly likely that this will be because a SSW is not far away and preconditioning is occurring.

[BLAST FROM THE PAST]

One thing that is most certain is that the likelihood of blocking from the present almost record cold stratosphere is extremely unlikely and if it does occur it is highly likely that this will be because a SSW is not far away and preconditioning is occurring.

Using current understanding, can this pre-conditioning be picked up on before hand?

BFTP

[chionomaniac]

I will add if you revisit the Nov 2010 Stratosphere thread you will note nobody predicted the extreme cold that was coming in late Nov/Dec even when it was only a couple of weeks away. Only the Met O knew what was coming!

Well that's not strictly true TEITS is it?

Whereas the extent of the cold spell was difficult to forecast, the first stratospheric changes were seen around the 5th of November - but I never at this point would be too gung ho about any cold spell at that point. However, by the 11th of November this was not the case.

Posted 11 November 2010 - 12:40

Today's update.

Yesterday, the T=240 forecast was suggesting some elongation of the stratospheric vortex at the 100 hPa level with the possibility of splitting. This remains the case today and interestingly this distortion of the vortex stretches right up to the top of the middle stratosphere. We have had a forecast of warming at the 10 hPa level which looks like occuring in the coming days without actually getting wrapped inside the vortex and it is probably this that is leading the change in stratospheric vortex profile. This can be seen quite clearly at the 10 hOa level on the ECM forecast.

The elongation is propagated right down to the 100 hPa level getting closer to the troposphere.

In fact at this level there is a suggestion of the vortex splitting but it is too early to say that this is going to occur.

The GFS is also suggesting a elongated vortex as the 30 hPA chart shows.

This type of event is always worth monitoring as a distorted vortex throughout the stratosphere will influence the tropospheric polar vortex positioning. It was the repeated splitting of the lower stratospheric vortex last year that led to polar air flooding southwards and northern blocking.

Cold spell on the way 10 days plus?

From this point on the cold spell was forecast through to it's beginning.

Using current understanding, can this pre-conditioning be picked up on before hand?

BFTP

Not really because not every preconditioned event will lead to a SSW. Rather like not every supercell drops a tornado.

More research needed to determine which do. Obviously strong wave events affect the stratosphere regularly and it is working out which ones are going to go 'the whole way' that difficulty lies.

Edited November 30, 2011 by chionomaniac

[UV-RAY]

Without having access to stratospheric vortex analysis charts for the preceding period it is very difficult to comment. However, the stratosphere at the start of December in 1987 at 30hPa was almost 10ºC warmer than it is presently. Wave number 1 activity was enhanced during the lead up to the cold spell and in fact it was the increased amplitude and repeated peaking of this wave that both led to the cold spell and subsequent SSW.

When looking at a SSW we need to analyse the period before and after the SSW due to the tropospheric/ stratospheric interactions that take place. It is a little bit disingenious to suggest that it is not linked - it is all linked together - but very complex.

So if we get a severe cold spell prior to a SSW it does not mean that there is no linkage, the warmer preceding December stratospheric spell, the increased wave number 1 activity, the drop in mean zonal winds, the evolution of the Scandinavian high all suggest that this is so.

One thing that is most certain is that the likelihood of blocking from the present almost record cold stratosphere is extremely unlikely and if it does occur it is highly likely that this will be because a SSW is not far away and preconditioning is occurring.

Chicken, egg, always springs too my mind.

[chionomaniac]

Chicken, egg, always springs too my mind.

Perhaps.

It seems to me that there is a small minority determined to disparage the stratospheric / tropospheric relationship rather than try to learn and understand more about it.

[BLAST FROM THE PAST]

C

with regards to TEITS comment of 2010, I think his suggestion is that the 'extremity' of the cold spell wasn't picked up on, not that there was a cold spell coming? I think that even GP had forecast heights to our NW at a latitude much lower than what happened. thats how I read it. Maybe TEITS can clarify?

BFTP

[Catacol]

Take a look at this link:

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/northpole/index.html

Very interesting table from lots of angles.

While these are running monthly averages for cold in the stratosphere, it does look as though we are entering a period of extreme stratospheric cold. GP cryptically alluded to the possibility of overspin of the vortex...

Is there a more detailed historical breakdown of weekly/daily stratospheric temps on the net? Apologies if that is a dull question - I am a lurker in a learning phase.

Is there any analogue data for what happens to temps in the stratosphere if it gets severely cold? There has to be a bounce back at some point, but if the cold is the severe is the bounce back "bouncier"? If the cold is so severe that wind speeds up there get very high, is there any data for what happens next? What is the out and out measured record for stratospheric cold?

So many questions... :-)

[BLAST FROM THE PAST]

Repetition so edited out

Edited November 30, 2011 by BLAST FROM THE PAST

[chionomaniac]

C

with regards to TEITS comment of 2010, I think his suggestion is that the 'extremity' of the cold spell wasn't picked up on, not that there was a cold spell coming? I think that even GP had forecast heights to our NW at a latitude much lower than what happened. thats how I read it. Maybe TEITS can clarify?

BFTP

I think the extremity of the (or any) event would be nigh impossible to forecast.

[BLAST FROM THE PAST]

Edited because computer at work is garbage and it keeps reposting!!!!

Edited November 30, 2011 by BLAST FROM THE PAST