Stratosphere Temperature Watch 2011/2012

[Azores Hi]

the 30mb temperature looks as if it MIGHT actually go through the average line-the first time this winter? Another 24 hours should show if it is going to break through.

Either way it's the first time it's even got close to average for 2 months! So can we take some hope in this alone that the PV will at least lose some of it's recent vigour?

[chionomaniac]

Ok, thanks Sebastian, So theres no SSW forecast but I thought that a big stratosphere warming was at least forecast for within the next 10 days?

The important bit here is not necessarily the warming, but how it affects the polar vortex. So far we see a reversal of the mean zonal winds forecast for the top of the stratosphere ( 1hPa) followed by a quick return of the reforming vortex. Lower down we do not even see a displacement enough to reverse the mean zonal winds in the mid stratosphere. The warmer stratosphere will affect the troposphere but this will not be as pronounced as a mid level propagation and full reversal and disintergration of the vortex would create.

Things could change but so far it does look like the unfavourable E-P flux could be an inhibiting factor some what.

For those still looking for wholesale tropospheric changes and instant high latitude blocking should hold out a little longer.

[EML Network]

IMO it's too little, too late, I think the best we can hope for , for the remainder of this winter is cold zonality, perhaps leading to a true northerly incursion on the back end of LP systems, that might, for a time take us into a North Easterly, but I doubt very much now that we will see a long lasting Northerly blocking pattern set up this winter, for me all eyes should now be on a Scandi High set up, although I have no idea how this works, and what it's effects actually are, just that I remember reading it somewhere..he he he

[geoffw]

is this big warming ever coming?

[Don]

The saga continues......

[phil nw.]

is this big warming ever coming?

We have had warmings Geoff and will continue to get them.However as Chiono explained they are affecting the upper layers presently but not far enough down to really disrupt the Vortex.There are definitely signs of vortex weakening as you can see on the 500hPa modelling as it`s shape is being distorted and fragmented.Even warmings higher up are slowing the mean zonal wind speeds.

I am afraid wrt to the timing and what effect of wavebreaking has on all the levels of the Strato.-is not an exact science.

All we can do is monitor and report the latest data and watch developments.

Edited January 10, 2012 by phil n.warks.

[chionomaniac]

We have had warmings Geoff and will continue to get them.However as Chiono explained they are affecting the upper layers presently but not far enough down to really disrupt the Vortex.There are definitely signs of vortex weakening as you can see on the 500hPa modelling as it`s shape is being distorted and fragmented.Even warmings higher up are slowing the mean zonal wind speeds.

I am afraid wrt to the timing and what effect of wavebreaking has on all the levels of the Strato.-is not an exact science.

All we can do is monitor and report the latest data and watch developments.

There is a critical few days coming up Phil, as far as I am concerned that could have implications for the rest of the stratospheric winter. Will the warming event now forecast around T+240 be enough to knock the vortex off its perch?

So far, we see the vortex at stretching point at this timeframe at 10 hPa but it then recovers and regains strength as the negative mean zonal mean winds are diverted equatorwards.

We need to see the opposite occur from T+240 onwards

[knocker]

This may be completely irrelevant but I'm out of my comfort zone here.

So far this winter it's been record breakingly cold and snowy in New Mexico and Texas with other parts such as S. Dakota and Illinois going in the other direction. I'm unsure why this should be so and I'm wondering whether the strength and position of the PV has any connection? I'm assuming a fairly weak La Nina is not connected. Apologies if this comes across as a fairly stupid question.

[Eugene]

as far as I am concerned that could have implications for the rest of the stratospheric winter

When do stratospheric warming events typically finish and what is the latest recorded date for a major SSW event?

Any chance of a colder spring this year with high latitude blocking in April or will we most likely continue the warm springs?

Edited January 10, 2012 by Eugene

[WINTRY WALES]

We have had warmings Geoff and will continue to get them.However as Chiono explained they are affecting the upper layers presently but not far enough down to really disrupt the Vortex.There are definitely signs of vortex weakening as you can see on the 500hPa modelling as it`s shape is being distorted and fragmented.Even warmings higher up are slowing the mean zonal wind speeds.

I am afraid wrt to the timing and what effect of wavebreaking has on all the levels of the Strato.-is not an exact science.

All we can do is monitor and report the latest data and watch developments.

HI,

From reading this very intresting topic over the last few weeks I was under the impression we were about to see a major SSW towards the middle to end of Jan?

Also this was to be off the scale to what has been present to date?

Thanks.

[phil nw.]

HI,

From reading this very intresting topic over the last few weeks I was under the impression we were about to see a major SSW towards the middle to end of Jan?

Also this was to be off the scale to what has been present to date?

Thanks.

I must admit i am unsure on this but i believe SSW events are somewhat different and rely on local weakbreaking from the bottom up-as far as i am aware W.W.

I don`t think i have seen any predictions on this and i don`t know whether they are easy to anticipate.

I bow to Chiono on this one as i am sure he will be able to explain more when he has time.

[sebastiaan1973]

When do stratospheric warming events typically finish and what is the latest recorded date for a major SSW event?

Any chance a colder spring this year with high latitude blocking in April or will we most likely continue the warm springs?

An overview of the SSW events. The latest was 23march 1965.

Edited January 10, 2012 by sebastiaan1973

[Kentish Kiwi]

An overview of the SSW events. The latest was 23march 1965.

There was an SSW in February 2010??

[Eugene]

Cheers for the table sebastiaan .

Quite a decent amount of SSW's in late Feb into March on that list so we have a decent amount of time yet, if i recall correctly it snowed early April 1989 around easter i think, on the table it says Feb 22 89 so just over 5 weeks later we got a cold ENE'ly, mmm very interesting.

Yes April 1989 was a cold month with some northerly blocking.

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00119890406.gif

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00219890406.gif

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00119890421.gif

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00219890424.gif

April. Cold. There was a heavy snowfall in the London area on the 5th, with 18 cms of snow at Tadworth (Surrey). There were damaging gales in the SW on April 11th, with a gust of nearly 100 mph recorded at Milford Haven, when the pressure was exceptionally low for April

Edited January 10, 2012 by Eugene

[mountain shadow]

Just had a look through the thread and couldn't see an answer to a question that came to me.

Why does the PV set up home around southern Greenland in the winter and not at the same latitude to the north of the British Isles for example?

Thanks in advance.

[chionomaniac]

Just had a look through the thread and couldn't see an answer to a question that came to me.

Why does the PV set up home around southern Greenland in the winter and not at the same latitude to the north of the British Isles for example?

Thanks in advance.

That depends whether you are talking about the tropospheric PV or stratospheric PV.. Stratospherically by the middle of winter the PV will be centrally placed after starting out over Siberia and Canada. The centrally placed PV will be enhanced tropospherically by the warm Atlantic interacting with cold Arctic air which leave the North Atlantic ripe for cyclogenesis in strong start PV conditions.

[mountain shadow]

Thanks Chino, I was talking about the 500hpa level vortex.

[damianslaw]

Doesn't the PV on average weaken substantially during February into early March regardless of how warm or cold the strat is.

[chionomaniac]

Absolutely nothing straightforward with the current projected warming and possible effects on the troposphere. We have more twists and turns this season than a series of The Killing. Update later.

[Weather-history]

Would it be fair to say that the stratosphere is like immiscible liquids in a test tube that don't mix well?

http://cdn.c.photosh...370509C-6RM.jpg

Give it a good shake like a warming and anything could happen. The greater the shake (or warming) the bigger the impact is likely to be. And with a shaken test tube the layers separate out gradually over time....

Or is that a totally wrong analogy?

Edited January 11, 2012 by Mr_Data

[chionomaniac]

Would it be fair to say that the stratosphere is like immiscible liquids in a test tube that don't mix well?

http://cdn.c.photosh...370509C-6RM.jpg

Give it a good shake like a warming and anything could happen. The greater the shake (or warming) the bigger the impact is likely to be. And with a shaken test tube the layers separate out gradually over time....

Or is that a totally wrong analogy?

I think it's more akin to heating a test tube full of liquid - but somehow with the test tube upside down and heating the curved base!

[EML Network]

I suspect by the time were all old n grey, that we'll still be none the wiser :-)

That's why it's such a fascinating subject, one moment you think you have a handle on things, and the next someone throws up a question you just don't know how to answer, or something unpredicted happens, and you don't know why.

nature is a fickle thing, and the phrase "butterfly effect", is quite possibly the best answer to give someone when trying to explain why it's almost impossible to be able to predict things so far out :-)

[TEITS]

That's why it's such a fascinating subject, one moment you think you have a handle on things, and the next someone throws up a question you just don't know how to answer, or something unpredicted happens, and you don't know why.

Indeed which is why in my opinion this is the best thread on the forum. Last year I was sceptical about the impacts of the stratosphere but CH was right this is because of my lack of knowledge on this subject. Im still struggling to understand this subject but thanks to CH and others im learning all the time.

[Eugene]

Indeed which is why in my opinion this is the best thread on the forum. Last year I was sceptical about the impacts of the stratosphere but CH was right this is because of my lack of knowledge on this subject. Im still struggling to understand this subject but thanks to CH and others im learning all the time.

Yes TEITS, your post sums up my thoughts perfectly, i also didn't take much notice of stratospheric warming events a few years back but ever since i have slowly come around to thinking they do have an impact on our weather down the line, excellent thread easily the best on any weather site and i keep checking back to read the experts views, learning all time like you say.

[UV-RAY]

Yes TEITS, your post sums up my thoughts perfectly, i also didn't take much notice of stratospheric warming events a few years back but ever since i have slowly come around to thinking they do have an impact on our weather down the line, excellent thread easily the best on any weather site and i keep checking back to read the experts views, learning all time like you say.

Same here, I was sceptical at first but this winter this thread has been fascinating. Just wish I could get my head around some of the science involved.