Stratosphere Temperature Watch 2011/2012

[phil nw.]

ECM output today continues the trend of zonal wind speeds decreasing through to day10

for comparison currently

-- then at T240

note the larger area of blue showing 0m/sec or in reversal.This is indications of the vortex slowing and weakening somewhat but at this stage not right through the levels.

Another point of interest bourne out by both ECM and GFS is the modelling of the core of the PV at the lowest level 100hPa as we go forward.

The centre of the PV in the lower Strato is forecast more towards Scandinavia with a troughing into Europe,coincidently similar to the 00z ECM Op.run.This would encourage a colder North Westerly tilt to the Jet later on.

Note too the warm area towards Alaska.This would favour any Arctic heights in that area,rather than Scandinavia, in the longer term.

I am interested to see how close the Strato modelling correlates to the trophospheric 500hPa output as we go forward.

The unknown is how much influence the buckling- or not- of the jetstream plays in this--obviously the more upstream buckling we can get the sharper any downstream ridging/troughing will be in our part of the N.hemisphere.

[chionomaniac]

Another hope on the distant horizon is another warming forecast at the upper levels of the strat in around 15 days time. We will have to wait around 5 days for the ECM to even pick this up!

[phil nw.]

Another hope on the distant horizon is another warming forecast at the upper levels of the strat in around 15 days time. We will have to wait around 5 days for the ECM to even pick this up!

I think that`s what`s called playing the long game Ed.!

If it does materialise it could be the one to disrupt a weaker vortex by then,but meanwhile we have no choice but to wait and monitor what we have.

[chionomaniac]

Latest update.

Actually, ECM charts haven't updated yet so I will wait!!

[chionomaniac]

The most interesting thing today is the warming GFS forecast at the 10 hPa level at T+240. I have seen warnings historically grow at this level and affect the strength of the vortex lower down. In fact it is far more use here than the massive warming at the 1 hPa level.

Still no ECM update today.

[sebastiaan1973]

Even at 348 it seems another wave 'hits' the 10hpa level. Perhaps I'm wrong but to me it seems we have wave after wave (?)

[chionomaniac]

Even at 348 it seems another wave 'hits' the 10hpa level. Perhaps I'm wrong but to me it seems we have wave after wave (?)

Yes, and this has been the theme for some time. One wave will be the straw that breaks the camels back.

[wxmatt]

It's been a super slow slog, but we are finally seeing some life in real-time:

[swfc]

can someone explain this mmw and ssw?thanks

[chionomaniac]

can someone explain this mmw and ssw?thanks

Hi swfc read the first post!

[swfc]

Hi swfc read the first post!

thankyou

[weatherjunkie]

Looks like another solid MT event. Frictional torque and AAM tendency still on the rise, so perhaps some more umph in this event.

Latest 10 hPa temp anomalies indicate significant warming in E. Asia/ N. Pacific relative to where our Ozone increase/wave breaking has occured. Looking at the forecasts for the upper stratosphere I still don't see much from the PV aside from movement toward Siberia.

It seems like this will be a long struggle.

[phil nw.]

Looks like another solid MT event. Frictional torque and AAM tendency still on the rise, so perhaps some more umph in this event.

Latest 10 hPa temp anomalies indicate significant warming in E. Asia/ N. Pacific relative to where our Ozone increase/wave breaking has occured. Looking at the forecasts for the upper stratosphere I still don't see much from the PV aside from movement toward Siberia.

It seems like this will be a long struggle.

Yes i don`t think we are going to see any rapid change over the pole-just gradual weakening as those zonal winds decrease.

The vortex core is modelled towards Scandi/Siberia as you say and this should at least turn the flow more North West in time.

[karyo]

Is the ECM on holiday? It hasn't updated for two days!

Any news from the gfs?

Karyo

[chionomaniac]

Still no ECM update!

I may have to make some enquiries if they are not updating tomorrow.

The GFS still keeps the predicted warming at the 10 hPa level, which need watching. With the very large MT event in progress we will have to keep a close eye on how the stratosphere reacts to any wave breaking events that follow these events.

c

[Glacier Point]

It's been a super slow slog, but we are finally seeing some life in real-time:

Indeed Matt, emphasising the very slow timescales we're working with.

Looking at the current plot, we can see how the cooling in early December appeared to fade and has resurfaced in the upper troposphere. The timescale for propagation about 15-20 days.

The propensity for warming or cooling events to be 'nodal' in their propagation has been well documented. 1981 was a good example of this.

I've added in the propagation lines for both warming and cooling events that winter and you can see the nodal propagation of the warming event and a timescale between four and six weeks for propagation.

The current strong Asian mountain torque should deliver another warming event in the next 10 - 15 days. Centred on 25 - 26 December, this looks to be around 4 - 10 Jan (with any downwelling impact on the tropopause 15 - 31 Jan). Sure enough 12z GFS forecast 10 hPa significant warming across Alaska.

So with our initial warming potentially impacting the troposphere mid January onwards and a second warming event preceeding it, could be a lot of interest in the Canadian Arctic through mid month. This is still well outside of most NWP tools' range.

Edited December 29, 2011 by Glacier Point

[Bristawl Si]

So with our initial warming potentially impacting the troposphere mid January onwards and a second warming event preceeding it, could be a lot of interest in the Canadian Arctic through mid month. This is still well outside of most NWP tools' range.

Thanks GP - so my interpretation of your post is that you still believe the mid to late Jan pattern change and subsequent transition to colder (and maybe snowier conditions) alluded to in your NW Winter forecast, is still v much on track?

Regards BB

[chionomaniac]

I think the nodal propagation of any warming event is evident in the 10 hPa warming forecast at T+240, following on from the 1hPa warming now. This too has been seen in previous years and I wonder how this will play out.

[lorenzo]

As La Nina has cropped up on the Tech thread here is a paper by one of the Stratosphere Meteorologists at NOAA regarding the link between SSW and ENSO, interesting statistics within..

butler+polvani-GRL-2011.pdf

[chionomaniac]

ECM has finally updated.

The overall picture shows that the large warming seen at the upper levels of the stratosphere is coming and going without affecting the lower levels in terms of mean zonal wind reduction. Remember the analogy of the distorted balloon - well that is what we are seeing. This is disappointing but perhaps not totally unexpected.

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.

One would expect some kind of Pacific ridge to develop in this scenario, and whereas we would not expect to benefit from this directly, it will be important to see in terms of stratospheric/tropospheric feedback mechanisms later in the season. Almost every SSW has been preceding by some sort of blocking event in the twenty days prior to a SSW, and it looks likely that this block in the Pacific could play an important role in this.

Already in the longer term GFS output we have consistent seen a greater warming forecast at the 10 hPa level and whereas this is still some time away, we have various pointers suggesting its likelihood. ( Asian MT, Pacific ridge feedback, increased ozone levels, previous warming and nodal propagation).

There is still a lot of winter left!

c

[lorenzo]

Looking at the JMA readings http://ds.data.jma.g...p_12z_st_nh.gif Looks like the transport is Poleward versus towards equator..

Edited December 30, 2011 by lorenzo

[phil nw.]

ECM has finally updated.

The overall picture shows that the large warming seen at the upper levels of the stratosphere is coming and going without affecting the lower levels in terms of mean zonal wind reduction. Remember the analogy of the distorted balloon - well that is what we are seeing. This is disappointing but perhaps not totally unexpected.

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.

One would expect some kind of Pacific ridge to develop in this scenario, and whereas we would not expect to benefit from this directly, it will be important to see in terms of stratospheric/tropospheric feedback mechanisms later in the season. Almost every SSW has been preceding by some sort of blocking event in the twenty days prior to a SSW, and it looks likely that this block in the Pacific could play an important role in this.

Already in the longer term GFS output we have consistent seen a greater warming forecast at the 10 hPa level and whereas this is still some time away, we have various pointers suggesting its likelihood. ( Asian MT, Pacific ridge feedback, increased ozone levels, previous warming and nodal propagation).

There is still a lot of winter left!

c

Yes signs of Vortex displacement towards our side of the Pole,ie Scandi/Siberia-still looks likely C.

ooz GFS in the later frames shows it may be picking this up.

[cooling climate]

ECM has finally updated.

The overall picture shows that the large warming seen at the upper levels of the stratosphere is coming and going without affecting the lower levels in terms of mean zonal wind reduction. Remember the analogy of the distorted balloon - well that is what we are seeing. This is disappointing but perhaps not totally unexpected.

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.

One would expect some kind of Pacific ridge to develop in this scenario, and whereas we would not expect to benefit from this directly, it will be important to see in terms of stratospheric/tropospheric feedback mechanisms later in the season. Almost every SSW has been preceding by some sort of blocking event in the twenty days prior to a SSW, and it looks likely that this block in the Pacific could play an important role in this.

Already in the longer term GFS output we have consistent seen a greater warming forecast at the 10 hPa level and whereas this is still some time away, we have various pointers suggesting its likelihood. ( Asian MT, Pacific ridge feedback, increased ozone levels, previous warming and nodal propagation).

There is still a lot of winter left!

c

If the warming verifies at 10mb that the GFS long range output shows

then this could imo lead to vortex split in the troposphere. Certainly one

to watch as it looks very similar to the conditions that caused a vortex

split during the middle of Feb 1979 which lead to a very blocked and

negative AO during the March of that year.

The last few runs of the GFS extended range model output is already

picking up on higher heights building over on the Alaskan side and then

pushing into the Arctic.

[Bobby]

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?

[phil nw.]

Latest ECM-at last updated,as Chiono pointed out earlier.

This is a good image of the forecast warming area over Alaska region down to 100hPa level by T168hrs.

Higher up at 30hPa again the warming showing and the signs of Vortex displacement towars Scandi.

Add some days on to this scenario-- and it fits in with the outer reaches of the last 2 GFS runs at T300 +showing heights at the 500hPa level.

here the 00z

and now 006z

Good evidence that the wavebreaking seen before Xmas is finally forecasted to have an effect on the stubborn vortex.

Looking at GFS Strato.output for expected pressure placement higher up at 10hPa T192hrs.

same picture Heights towards Alaska-Vortex pushed towards Scandinavia.

This looks more and more to me like a vortex displacement rather than a total split-unless we get further warmings later.

Those zonal wind forecasts,although trending weaker are still too strong to allow extensive disruption.

So the data shows the warming,such as we have had to date,steadily extending to lower levels-with time and likely to cause some changes,which are just starting to show in the late GFS output.

Edited December 30, 2011 by phil n.warks.