Stratosphere Temperature Watch 2011/2012

[phil nw.]

Below is the 30 mb temperature map at t0 which is similar to the one you show.

This is the 30 mb temperature map at t 192 which shows temperatures over the pole at

around - 45c approximately 35c warmer.

This should have a big impact down the line.

Sorry this is the map I intended to post.

Quite possibly CC.

It points to a displacement towards Scandinavia -which is something i have been looking at for what seems like weeks now.Possible Northerly later on?.

GFS 192 hrs. here

However this is at 30hPa and what influence and timelag is involved to affect the 500hPa patterns i wouldn`t know.

[Don]

It does seem to be a bit up and down on this thread at the moment, i.e one day things look very promising with the strat but not so much the next day etc. There was a positive mood on here yesterday but it's quite dfferent today! Illustrates the uncertainty I suppose.

Edited January 8, 2012 by Don

[damianslaw]

It does seem to be a bit up and down on this thread at the moment, i.e one day things look very promising with the strat but not so much the next day etc. There was a positive mood on here yesterday but it's quite dfferent today! Illustrates the uncertainty I suppose.

Yes this post was alive with activity last night - the busiest I've seen it, with everyone in bouyant mood. However, today it seems everyone has the sunday blues....

[Cloud 10]

Still some huge warmings forecast at the top of the stratosphere,as well as lower down at 10mb.

1mb> 10mb>

Something has to give sooner or later.

[HotCuppa]

where is the direct evidence that strat warming actually influences our weather here in the UK? I remember a few years back, when we had a warm strat and nothing happened at all, infact we continued to remain mild.

[chionomaniac]

I don't think that it is doom and gloom in this thread. I know my emotions don't get swayed up and down by every run.

All I have suggested today is that I have concerns about the propagation of the warmings that have occurred so far and that have been forecast up to T+240. There is still the largest warming at that timeframe that we do not know how any propagation might occur.

There is still a lot of promise, but one should be cautious as well.

[Great Plum]

I know I should let someone more knowledgable answer Hot Cuppa's question... But, the way I understand it, start warnings don't necessarially plunge the uk into cold. However, it makes northern blocking more likely which in turn makes it more possible for colder air to come to these shores...

Edited January 8, 2012 by Great Plum

[lorenzo]

Don't think there is gloom here, however if you are feeling that way here is a game of pick your analog..

Looking through these, there are 7 split vortex patterns in the month of January out of the 17 listed. 1968 and 1985 have the most similar ENSO pattern with DJF of -0.7 and -0.9 respectively.

Have fun digging through the archives

Edited January 9, 2012 by lorenzo

[weatherjunkie]

I don't think that it is doom and gloom in this thread. I know my emotions don't get swayed up and down by every run.

All I have suggested today is that I have concerns about the propagation of the warmings that have occurred so far and that have been forecast up to T+240. There is still the largest warming at that timeframe that we do not know how any propagation might occur.

There is still a lot of promise, but one should be cautious as well.

Why is it that EP fluxes must be poleward? I understand that this aids in propagation of momentum and heat from the planetary waves to the poles (and deceleration of westerlies). How this transfers to the lower levels of the stratosphere and then troposphere is a concept I still struggle with. The only thing I can think of is tropospheric/lower stratosphere poleward EP flux to help decelerate westerlies and allow for the upper stratosphere warming to filter down.

Speaking of decelerating westerlies. Looking at the ECMWF zonal mean forecast charts we see that by 240 the high latitude upper level westerlies are completely removed. Something else to keep an eye on.

[sebastiaan1973]

No improvement concerning the EP Flux. At the end of the forecast they are not poleward oriented.

Furtheron there is a forecasted positive zonal wind at 30hpa, 60n, although we do see a decrease.

In the coming days we also see a reverse zonal wind at lower heights. Illustrated in the forecast for 6 days ahead.

[Duane S.]

Someone correct me but this seems incredibly progressive from day 7 through to day 8?

[chionomaniac]

Why is it that EP fluxes must be poleward? I understand that this aids in propagation of momentum and heat from the planetary waves to the poles (and deceleration of westerlies). How this transfers to the lower levels of the stratosphere and then troposphere is a concept I still struggle with. The only thing I can think of is tropospheric/lower stratosphere poleward EP flux to help decelerate westerlies and allow for the upper stratosphere warming to filter down.

Speaking of decelerating westerlies. Looking at the ECMWF zonal mean forecast charts we see that by 240 the high latitude upper level westerlies are completely removed. Something else to keep an eye on.

Hi weatherjunkie,

The concept of E-P flux is a difficult one to understand I agree as it is all interlinked with any distortions that are occurring to the vortex.

The great warming forecast to upper levels is (forecast to be) propagating well to around 10 hPa where we have yet to see its greatest impact.

From thenonwards it is almost as if the severe displacement already experienced by the vortex is working against further propagation by diverting the descending wave equatorwards as seen below at the 30 hPa level.

I am not saying that this is not subject to change as it looks like the vortex will be completely destroyed at 1 hPa level and we will have to see how further propagation occurs.

What we are seeing already is a large drop in the vortex strength from the previous warmings.

[geoffw]

what tiimescales are we looking at?

[chionomaniac]

what tiimescales are we looking at?

For what Geoff?

[geoffw]

sorry, i meant opportunity for cold

[chionomaniac]

sorry, i meant opportunity for cold

Truth be told Geoff there are great opportunities from 10 days plus from the mean zonal wind reduction from earlier warmings of the upper strat filtering through. I think that we should concentrate on that presently and monitor the ongoing situation further up.

When looking at the 100 hPa we see a three leafed clover shape (ahem) with a weakened and very reduced vortex.

It is this that interests me most of all because the vorticity centres here kleave a number of options open - most of them good for cold lovers.

Still a lot of volatility expected in the tropospheric NWP output as a result.

[cooling climate]

Hi weatherjunkie,

The concept of E-P flux is a difficult one to understand I agree as it is all interlinked with any distortions that are occurring to the vortex.

The great warming forecast to upper levels is (forecast to be) propagating well to around 10 hPa where we have yet to see its greatest impact.

From thenonwards it is almost as if the severe displacement already experienced by the vortex is working against further propagation by diverting the descending wave equatorwards as seen below at the 30 hPa level.

I am not saying that this is not subject to change as it looks like the vortex will be completely destroyed at 1 hPa level and we will have to see how further propagation occurs.

What we are seeing already is a large drop in the vortex strength from the previous warmings.

I know the maps show are at the 30 mb level but I wonder if lower down towards the troposhere this would equate to a developing and deepening low pressure system ( or piece of the vortex) which would further

aid in the building of heights to the left over the bering sea and subsequently over the Arctic.

Just a thought.

Edited January 9, 2012 by cooling climate

[AWD]

Just to see if I got this right Chio, any warming of the Strat, no matter how major ( or indeed any SSW in the future ) will be irrelavent if the EP Flux doesn't play ball and head poleward?

To get sustained cold to the UK in the remainder of this winter, we will need a change in the EP Flux?

[chionomaniac]

Just to see if I got this right Chio, any warming of the Strat, no matter how major ( or indeed any SSW in the future ) will be irrelavent if the EP Flux doesn't play ball and head poleward?

To get sustained cold to the UK in the remainder of this winter, we will need a change in the EP Flux?

Good question.

And I think the answer is no. We have already had sufficient warming with only a slight period of time with a favourable E-P flux that is already showing that it can weaken th polar vortex tropospherically. However the Japanese study showed that the best propagating SSWs had poleward fluxing. They limited the study to SSWs though. So there is a certain amount of unknowns in there as well.

[Weather-history]

What I find confusing is the ECM forecasts a dsplacement of the stratospheric vortex towards Siberia but the 500hpa charts suggest higher pressure for that region instead within that timeframe.

[Snowman31]

Hi Chio, probably a stupid question but theres something I don't understand. An SSW is predicted for about 8 or 9 days time if I i'm correct but all the models seem to be strengthening the PV around that time instead of weakening it. Why would that be, is it because of the EP Flux?

Edited January 10, 2012 by Snowman31

[sebastiaan1973]

No SSW is forecasted. See the chart, no reverse zonal wind at 10hpa, 60N.

EP Flux is still not good at day 5-10.

Edited January 10, 2012 by sebastiaan1973

[Snowman31]

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?

[chionomaniac]

What I find confusing is the ECM forecasts a dsplacement of the stratospheric vortex towards Siberia but the 500hpa charts suggest higher pressure for that region instead within that timeframe.

Probably that the strength of the tropospheric Siberian high overrides the stratospheric polar vortex displacement signal.This is changing as well with the stratosphreric vortex reducing further and becoming displaced further - towards the UK and Atlantic sector at upper levels.

[johnholmes]

Probably that the strength of the tropospheric Siberian high overrides the stratospheric polar vortex displacement signal.This is changing as well with the stratosphreric vortex reducing further and becoming displaced further - towards the UK and Atlantic sector at upper levels.

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.