Stratosphere Temperature Watch 2011/2012

[cooling climate]

Yes a big warming has been starting to show up at the end of the GFS run lately. Also it seems to spread towards the Pole/Greenland

Could these repeated warmings have a cumulative effect on thnigs?

Yes that is the warming I was refering to. Could be the one to break

the Camels back so to speak,if it verifies of course.

[karyo]

Nice to see the ECM updating at long last.

The zonal winds are dropping quite nicely at the moment but are expected to pick up again in a few days time!

Regarding the stratospheric temperatures, the 30hpa level is a concern for me as it hardly seem to respond to the warming at the 10hpa level.

http://wekuw.met.fu-...ww/wdiag/ts.php

We have to hope for a much stronger warming soon.

Karyo

Edited December 30, 2011 by karyo

[chionomaniac]

Yes that is the warming I was refering to. Could be the one to break

the Camels back so to speak,if it verifies of course.

I am beginning to think that it is a little bit too much of a case of jam tomorrow. That warming in FI has been there most runs but never seems to get any closer. I am tempted not to look at anything past the usual 10 day outlook that I have looked at the last few years.

[johnholmes]

very sensible chio-it is like any other prediction-a prediction and we all know that they do tend to tittilate and tantalise for whichever weather preference we have and then, at times,go the way of the pear.

A touch OTT but there are so many links that have to be in place that we know of and probably the odd one we may not know of yet that its very difficult to get them all on board.

Even then, remember was it 2007? ALL from the 30mb temperature, ENSO, MJO, AO, NAO, 500mb anomaly charts, synoptic models down to T+96 or perhaps T+72 predicted biting cold from the east. Result-no, so caution always!

[k19]

can somebody please explain to me what a mountain torque event is? I can't find information anywhere

[lorenzo]

Mountain ranges, such as the Sierras of North and South America, place an obstacle in the path of the westerly winds.

Such a blockage tends to generate a high-pressure region upwind from the mountains - this may be viewed as air piling up as it prepares to jump the hurdle, and a low-pressure area downwind.

Thus, there is a stronger push against the mountains on the high-pressure western side than on the low-pressure eastern side.

The net effect is the slowing down of the atmospheric flow, Mountain Torque.

http://www.esrl.noaa.gov/psd/map/images/reanalysis/aam_total/gltaum.90day.gif

[Bishop Brennan]

Thank you for that explanation Lorenzo, very much appreciated. I have to say, I'm finding this thread absolutely fascinating reading

Bish

[Weather-history]

However, there is some effect of the warming in the distortion of the polar vortex and displacement to the Siberian sector. This is occurring throughout the whole height of the stratosphere right down to the troposphere.

c

A displaced vortex to Scandinavia and Siberia was a feature of January 1941

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410101.gif

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410101.gif

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410111.gif

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410116.gif

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410125.gif

http://www.wetterzentrale.de/pics/archive/ra/1941/Rrea00119410130.gif

[Relativistic]

A displaced vortex to Scandinavia and Siberia was a feature of January 1941

http://www.wetterzen...00119410101.gif

http://www.wetterzen...00119410101.gif

http://www.wetterzen...00119410111.gif

http://www.wetterzen...00119410116.gif

http://www.wetterzen...00119410125.gif

http://www.wetterzen...00119410130.gif

Is this also similar to January 1987?

Forgive me if I've done this wrong, I'm still getting use to some of these charts.

Edit: Just realised that this is displaced over Greenland as well.

Edited December 31, 2011 by 22nov10blast

[k19]

Mountain ranges, such as the Sierras of North and South America, place an obstacle in the path of the westerly winds.

Such a blockage tends to generate a high-pressure region upwind from the mountains - this may be viewed as air piling up as it prepares to jump the hurdle, and a low-pressure area downwind.

Thus, there is a stronger push against the mountains on the high-pressure western side than on the low-pressure eastern side.

The net effect is the slowing down of the atmospheric flow, Mountain Torque.

http://www.esrl.noaa...ltaum.90day.gif

Thanks very much for the explanation, but how does the mountain torque affect the stratosphere above the poles?

[chionomaniac]

With the ECM back on another festive break we only have the GFS to go on today.

This is promising with another medium strength warming forecast at the 10 hPa level at T+240.

This could go either way but if the mountain torque creates another wave breaking event then this warming could increase in size and importantly break into the stratosphere at the lower 10 hPa level ( rather than 1hPa).

The extended T+300 GFS 6Z forecast is very promising but more unreliable.

Looking lower down towards the troposphere at the 100 hPa level, there is no compelling evidence if and where blocking will break into the polar vortex yet, though the tropospheric modelling is now showing signs of this becoming more likely as the month progresses. This is certainly backed up stratospherically wise, but deciding where this could occur a real challenge.

Last chart is an FI one from 100 hPa today from the GFS 6Z. Now wouldn't that be nice for the New Year?

c

Thanks very much for the explanation, but how does the mountain torque affect the stratosphere above the poles?

Hi K.1000.

The MT events deflect the Rossby waves as they pass over the mountain ranges. This can be to latitudes further south and dispersion occurs, or into the stratosphere. If the wave has sufficient amplitude then it can break into the stratosphere rather like a wave over rocks into a settled rock pool. The stratospheric polar vortex, of course, is not a settled rock pool, but a strong circular rotating vortex with a barrier at its edge of higher velocity winds, but this barrier (known as the surf zone) can be broken into, if the wave is strong enough. Hence mountain torques affect the polar vortex by allowing collections of warmer air just outside the surf zone, to be introduced into the vortex, weakening it and displacing it from its central position.

Edited January 1, 2012 by chionomaniac

[johnholmes]

c

Hi K.1000.

The MT events deflect the Rossby waves as they pass over the mountain ranges. This can be to latitudes further south and dispersion occurs, or into the stratosphere. If the wave has sufficient amplitude then it can break into the stratosphere rather like a wave over rocks into a settled rock pool. The stratospheric polar vortex, of course, is not a settled rock pool, but a strong circular rotating vortex with a barrier at its edge of higher velocity winds, but this barrier (known as the surf zone) can be broken into, if the wave is strong enough. Hence mountain torques affect the polar vortex by allowing collections of warmer air just outside the surf zone, to be introduced into the vortex, weakening it and displacing it from its central position.

another first class explanation chio-what would some of us do without you?

[shuggee]

With the ECM back on another festive break we only have the GFS to go on today.

This is promising with another medium strength warming forecast at the 10 hPa level at T+240.

<SNIP>

I think it's worth a cautionary post amongst the current 'pattern change' in mid January narrative.

The charts at T+240 are 10 days into the future - and are a forecast. That means it will be 11 Jan 2012 if that chart verifies. We know from past experience that any warming of the stratosphere actually has to happen first - and then we have to wait 3 - 4 weeks to see any effect at surface here in the UK. That's the beginning of Feb,

For perspective here's today's stratospheric temps:

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

[phil nw.]

I think it's worth a cautionary post amongst the current 'pattern change' in mid January narrative.

The charts at T+240 are 10 days into the future - and are a forecast. That means it will be 11 Jan 2012 if that chart verifies. We know from past experience that any warming of the stratosphere actually has to happen first - and then we have to wait 3 - 4 weeks to see any effect at surface here in the UK. That's the beginning of Feb,

For perspective here's today's stratospheric temps:

http://ds.data.jma.g...e/pole30_n.html

We musn`t forget the initial wavebreaking that`s already occured though and indeed effects of this are filtering down and starting to show in the later Trophospheric modelling.

What is in doubt is how this will reshape the vortex.At this stage i still think we should look more for a displacement towards Scandi/Siberia and some Alaskan heights as shown by the warm sector on the Strato Images.

Then we have to get lucky ,if looking for cold,that we end up on the cold side of any downstream troughing.

Edited January 1, 2012 by phil n.warks.

[shuggee]

Yep Phil I think all that is true - there's a long pile of dominoes that have to fall and it is encouraging that there are more fingers forecast to push the stubborn ones that break the chain. Just wanted to bring a hint of caution into the discussion

[chionomaniac]

Very wise to be cautious shuggee. Of course, I know all the pitfalls and I am cautious with my own expectations but my own caution may not be transferred across in my posts.

However as Phil correctly states the first wave has broken through.

Here is the temperature profile today at 1 hPa

Which has already caused a displacement of the vortex today at 10 hPa

This can already have knock on effects lower down.

[phil nw.]

Yep Phil I think all that is true - there's a long pile of dominoes that have to fall and it is encouraging that there are more fingers forecast to push the stubborn ones that break the chain. Just wanted to bring a hint of caution into the discussion

Yes i understand where you were coming from and i am cautious about getting straight into a cold evolution but for a slightly different reason --the one i mentioned above.

Based on all available data,change is likely around mid-month but we certainly can`t take for granted that it will fall right for cold in the UK. immediately.

The positive way to view this though is that with N.Blocking it does increase our chances of a colder spell as locked up cold has to go south somewhere.We just need those wavelengths to fall right for this.

[chionomaniac]

Well with the ECM back on again so time for another update.

Firstly, we see some agreement between the ECM and GFS with regards to another warming at the 10 hPa level.

In fact we are seeing varying degrees of warmings continually bouncing off the surf zone, weakening the vortex as they do so. Here is the latest at T+ 240. Note shuggee that this is just another peak during the continual surf zone attack.

The vortex displacement and elongation is carried right down to the 100hPa level though the vortex is still forecast to be more centrally placed here - that is why any amplification in the tropospheric flow is still struggling to break through the Greenland area - so far.

However it should be noted that the 100 hPa mean zonal 60ºN winds are forecast to reduce slowly over the next ten days. This is crucial as the tropospheric vortex strength will reduce in line with this and it won't be long after that we see further blocking solutions offered.

More importantly, with there being no sign of let up in the warming of the middle stratosphere we are likely to see tropospheric high latitude blocking chances increase as time progresses - even without a SSW.

So all in all the promise for the second half of January is very much welcome. Lets hope that we are on the receiving end of any cold that heads south!

c

[chionomaniac]

Paper for GP ( you may have read it). It highlights Vortex Intensification events.

http://www.mri-jma.go.jp/Dep/cl/kuroda/2007JD009550.pdf

[chionomaniac]

GFS update still good at 10 hPa with a stronger warming forecast today for T+240:

And we have signs today of an upward split of the vortex at T+216 up to 70 hPa. Encouraging for future Scandi height rises after a trough has dropped into Europe.

[Bobby]

A decent warming showing at just +168 on GFS

[karyo]

A decent warming showing at just +168 on GFS

Is this an upgrade to what it was showing yesterday?

I get the feeling that the stratospheric warming is developing too slowly to save January from being another mild month. February is our best chance I think.

Karyo

[Relativistic]

Has anyone got any links that they can give me for zonal wind forecasts?

Thanks.

[bluearmy]

Has anyone got any links that they can give me for zonal wind forecasts?

Thanks.

Go to page 1 of the thread and click on the ecm (berlin) link provided by chio. zonal wind forecasts are in the bottom box

[Relativistic]

Go to page 1 of the thread and click on the ecm (berlin) link provided by chio. zonal wind forecasts are in the bottom box

Okay, thanks. About the EP Flux, at 10hPa it is and has been in a poleward direction, yet the warming at 10hPa hasn't really propagated downwards. Am I wrong in saying that this is what should happen or is there a reason for this?

Edited January 3, 2012 by 22nov10blast