Stratosphere Temperature Watch

[chionomaniac]

Throughout the winter, CN, NSCC, GP, JH and others, you have kept us updated on a daily basis regarding events surrounding our stratosphere and this thread is a credit to all of your efforts.

SA. :winky:

Thanks SA for your kind words.

Hi M

Edit: according to latest forecasts it won't be until 26th Feb that both 10hPa and 30hPa zonal winds have returned to westerly. So that will be a period from 23 Jan to 26 Feb that zonal winds at these levels will have been easterly. So maybe will have to wait till then until anything more definitive is picked up?

Even after the zonal winds turn westerly at the 10 hPa and 30 hPa levels at 60N there will still be a large section of stratosphere under the influence of easterly winds so we still may have to wait a little while longer for propagation.

I haven't written off the MMW producing something yet. I just feel that the ECM zonal wind forecasts are not to be trusted at a greater than 3 day range. So something may pop up and effect at quite a short timespan! I will keep watching.

c

[Gray-Wolf]

I'm still thinking that there are 2 ways of promoting the initial warming and you guys have done a fantastic job of explaining and forecasting 'Type1' (bottom up impact) but ,this event was 'Type2' (top down impact).

I too cannot dismiss impact down the line.If you slosh a bucket of water around there id no telling (if you sloshed it randomly) where positive/negative interference will occur.

Slosh the bucket in a 'controlled way then you can predict (roughly) where the events will take place.

I think this was a 'random sloshing' of the bucket and the energies imparted are still washing around ,though dissipating within the strat.

But then ,What do I know???

[Guest North Sea Snow Convection]

Am i right in thinking that we have a warm layer, of easterly winds, effectively bottled up in the lower stratosphere and waiting to be pushed into the the trophosphere by a cooling of the stratosphere higher up? if so as long as this propogates down eventually we could still be looking at a cold march. It's not possible that these easterly winds can have vanished so surely they must reach the surface eventually, right? Or was this MMW the final warming and no significant stratosphere cooling is going to occur and force them down?

Matt

Hello Matt

Yes, you are on the right lines regarding the trapping of the warmer layers above a cooler surface layer. A FW did seem a possibility at one time but there are signs that a cooling at the higher levels of the stratosphere is underway for the moment although the zonal winds as chionomaniac says are staying easterly for a bit still in some areas of the stratosphere. It could be that the FW is now reversed for a more traditional time later in the Spring - but we will have to see. There is a lot of uncertainty about the short term to clear up yet.

Still very much could be that the MMW effects are delayed but may become apparent yet as we go into March. Seem to to be saying the same each day but the watching and waiting goes on..and on!

GW's analogy of the 'sloshing bucket' is quite a good one. It helps explain the uncertainty.

Edited February 19, 2009 by North Sea Snow Convection

[chionomaniac]

I'm still thinking that there are 2 ways of promoting the initial warming and you guys have done a fantastic job of explaining and forecasting 'Type1' (bottom up impact) but ,this event was 'Type2' (top down impact).

I too cannot dismiss impact down the line.If you slosh a bucket of water around there id no telling (if you sloshed it randomly) where positive/negative interference will occur.

Slosh the bucket in a 'controlled way then you can predict (roughly) where the events will take place.

I think this was a 'random sloshing' of the bucket and the energies imparted are still washing around ,though dissipating within the strat.

But then ,What do I know???

The way that I see it is that a type 2 wave entered the lower stratosphere from the tropical troposphere travelled polewards up to the top height of the stratosphere and then crashed downwards through the stratosphere creating the MMW as it did so. The reversal of zonal winds has been slow to dissipate like the random sloshing of the bucket I would agree.

[tundra]

Just been on the solar cycle 24 forum and apparently on the 21and 22 of Jan the magnetosphere was hit by what they call a SGR (soft gamma repeater) with over 800 bursts, it can be seen on you tube if you type in magnetosphere blast 21-22 Jan.

I wonder what effect if any this had on the stratosphere warming.

[chionomaniac]

Just been on the solar cycle 24 forum and apparently on the 21and 22 of Jan the magnetosphere was hit by what they call a SGR (soft gamma repeater) with over 800 bursts, it can be seen on you tube if you type in magnetosphere blast 21-22 Jan.

I wonder what effect if any this had on the stratosphere warming.

The warming and zonal wind reduction had started well before this magnetosphere event and has good correlation with a troposphere type 2 wave breaking event so it is difficult to say how much effect this had in causation of the MMW. Looking back have other SGRs with large bursts had similar effects?

The main question that we need to have answered is why have all the negative zonal wind anomalies been trapped in the middle stratosphere and not ( after the initial burst) been propagated down into the troposphere. It appears that the stratosphere/troposphere have been interconnected and influencing each other consistently well all winter until after the initial burst of negative winds from the MMW. Since then it appears that the troposphere has acted independently (almost trapped in a weaker westerly vortex) despite the middle stratospheric vortex being split and mean easterly winds persisting there. Why has that inversion state that GP touched upon persisted? Is it due to the dynamics of the whole stratosphere with the corresponding stronger westerly stratosphere and troposphere at 30-40ºN been fundamental in keeping the easterlies persisting where they are? Does the positive QBO towards the equatorial region at the 30-50 hPa level play some integral part in the whole dynamic system? After all we are seeing the first ever recorded MMW occurring during a positive QBO and solar minimum.

At the start of winter we were thinking that there would be no chance of an MMW this year and yet we have experienced the greatest MMW ever recorded. Answers to these questions will hopefully help us understand this event and be able to predict the outcomes of future events.

c

Edited February 19, 2009 by chionomaniac

[Cecil Hogmanay Melchett]

Just wanted to say thankyou for all the hard work and endeavour that has gone into this thread through the winter.

It has been without doubt the best thread on NW and kudos to GP chionomaniac Tamara MRData and all the others who have made this thread what it is.

Wouldn't it be ironic if we saw a big freeze up in the strat next winter and see tremendous northern blocking.

Just a thought!

[Guest North Sea Snow Convection]

Ultimately perhaps, despite the uniqueness of a strong MMW with a +QBO/solar min, the westerly phases has had the final say and is why we are still waiting for an effect which might not conceivably materialise at all and just be carried on eventually into the eventual FW.

Even the most dramatic events don't manifest themselves necessarily in any significant way. The study is still very interesting for all that, even if the outcome may yet be an anti-climax. But we don't know for sure yet what will be.

Thanks HD for your comments - hopefully another watch can be undertaken next year. This one still has yet to conclude of course!

Edited February 20, 2009 by North Sea Snow Convection

[karyo]

Just wanted to say thankyou for all the hard work and endeavour that has gone into this thread through the winter.

It has been without doubt the best thread on NW and kudos to GP chionomaniac Tamara MRData and all the others who have made this thread what it is.

I'll second to that! This has been without a doubt the most worthwhile thread of net weather this winter season. One that has promoted learning and i'll be very keen to follow it again next winter.

I still think that northern blocking will take place in March as the delayed propogation takes place.

Karyo

[johnholmes]

Even when the 'season' has finished there is still unfinished business.

That is to try and work out why with such a dramatic warming little, in the time scales we have been using this winter, gave any cold. Not for this area.

What do we need to look at to try and discover a more reliable way of attempting to predict cold weather for the UK area two to 3 weeks down the line.

I've been looking at two of them, AO and NAO and there are some apparent links but I need to check further.

What effect have SST's in various places had?

I'm sure there are others but I will be very surprised if this discussion does not carry on with a few of us trying to come up with, at least, some answers through the coming months.

My thanks to those who have contributed to it and to C for starting it.

Edited February 20, 2009 by johnholmes

[MR EXTREMES]

yes indeed ive been very critical of the sw events.

but cant take away the effort and work thats been put into this forum.

ok yes im dissapointed with the fact that this current event didnt really effect us,

and im still a little skeptical but i also understand that other climate issues have to come into the picture for this event to become sucessfull event as i feel it may have played a little part in febuary and maybe decembers aswell although im not truely convinced.

thats why this issue should always play a part in net weather Discussions.

indeed it may not be over yet i hope im proven wrong and i hope march springs some suprises.

and if this event is true to helping with colder winters,

then also this must be the case for hotter summers,

if its proved to be worthy,it could be a good tool for forecasting and like john said outlooks.

:lol: :lol:

[johnholmes]

just to put something in for people to comment on if they wish

How did the various changes in 30mb temperatures reflect at my weather station?

Was there any link?

Using just the actual 30mb temperatures and using the suggested time lapse of from 15 to 25 days for these temperatures to have any possibly effect on our weather I show the following.

Below is the 30mb temperature curve with its departures from normal

Below are the dates I have taken from where it crosses the average line both warming and cooling.

1 1 November = ‘cold’ possible from 15 or 25 November

2 15 November=’mild’ 25 November or 5 December

3 1 December= ‘cold’ 15 December or 25 December

4 16 December=’mild’ 31 December or 10 January

5 20 January=’cold’ 4 February or 14 February

Yes I know my weather is but one tiny speck in the northern hemisphere but it might allow some comparisons to be made.

1 There was a shortish cold spell with 2 air frosts and snow on two days 22-23 November and another spell began 29th. This one lasted to about 17 December with frequent air frosts and snow just on two days, 2nd and 4th December.

2 There was no ‘mild’ until late November then again in December, from about 18th-24th.

3 It became coldish from the Xmas period, 24-26th and this lasted until 11 January when it became somewhat less cold but only ‘mild’ on a couple of days.

4 There was no mild at the end of December and, as shown at 3, it became less cold from about 11th January, cold zonal might best sum it up, with one or two milder days.

5 It became cold or even very cold on 1 February and continued to 15th when milder days took over.

I leave it for the reader to make their own mind up on whether, if taken with other indicators; there has been any link this autumn and winter, so far, with the 30mb temperature departures from normal and UK weather.

[The PIT]

Even when the 'season' has finished there is still unfinished business.

That is to try and work out why with such a dramatic warming little, in the time scales we have been using this winter, gave any cold. Not for this area.

What do we need to look at to try and discover a more reliable way of attempting to predict cold weather for the UK area two to 3 weeks down the line.

I've been looking at two of them, AO and NAO and there are some apparent links but I need to check further.

What effect have SST's in various places had?

I'm sure there are others but I will be very surprised if this discussion does not carry on with a few of us trying to come up with, at least, some answers through the coming months.

My thanks to those who have contributed to it and to C for starting it.

Hope people do keep discussing it as it would very educational for the last informed like myself. Interesting subject.

[johnholmes]

also this link to something I posted in a blog a few days ago

http://www.netweather.tv/forum/index.php?showtopic=53715

[Glacier Point]

Small but significant downward movement of zonal winds 50 - 150 hPa layers in the last few days which is likely to bring about a -AO for a time (given that the atmosphere beneath it is warm).

Latest thermal profile highlights the extent of MMW:

[chionomaniac]

also this link to something I posted in a blog a few days ago

http://www.netweather.tv/forum/index.php?showtopic=53715

I think what you have done here and in your previous post earlier John, is highlighted the difficulty in measuring tropospheric responses to stratospheric changes. What you have shown is how temperature changes at one point many miles up in the stratosphere above the North Pole, may have had a delayed influence on the tropospheric temperature at on point on the surface thousands of miles away. What will be amazing is if there is any correlation at all!

After following the stratospheric / tropospheric interactions so far this winter there is one thing that I am slowly learning is that dealing with very specific responses is best avoided. However, even dealing with trends is quite difficult. The very limit that I think that we can look at is the general pattern of warmings and subsequent vortex position and strength of the stratosphere and try and match to the strength and position of the tropospheric jetstream and subsequent mid to high latitude blocking highs across the whole Northern Hemisphere. One can probably guess that is some undertaking requiring a fair bit of work. Even then we have to deal with the MMW which has so far failed to propagate down to the troposphere in a manner that we have may have expected!

Looking back to the start of winter and we experienced what I suspect to be a Canadian Warming.

When you monitor this as a North Pole 30 hPa temperature reading one does not see the full picture ie how it developed and the position of the upper stratospheric vortex and whether this could have had an influence on the northern arm of the tropospheric jetstream either in intensity or possible axis of flow? With Tamara previously providing food for thought on previous frequencies of CWs and PDO shifts to me I find myself asking more questions than I can possibly find answers to. By the end of December we found ourselves under the influence of the a mid latitude block with the jetstream orientated NW to SE.

Was this as a consequence of the CW earlier in that month?

There is a lot to analyse from this winter and we are still in the middle of a MMW, so this thread has far from finished and I will keep monitoring the stratosphere until the end of March. Even then, as GP has mentioned in another thread, the state of the stratosphere at the end of winter can be another factor that helps set the summer pattern so more to discuss there in the spring (that may warrant its own thread)

Thanks to HD, Karyo and bb657 for their kind comments earlier.

[tundra]

Chionomaniac i would not call that a typical canadian warming, to far west. Its certainly further west than the canadian warmings i have read about and the canadian warming in dec of 62.

Just briefly touching on the high latitude blocking of 62/63 i think the Tsar bomb that was detonated some 12000 feet above Novaya Zemlya in Oct 1961 played its role in the severe winter that followed a year later.

I would think its safe to assume that every proper high latitude block is the result of a warming in the stratosphere and that if you had the data to look much further back in time their would be a very high correlation.

I have often wondered what effect corona mass ejections from the sun have on the stratosphere especially if you have an otherwise quiet sun with little activity.

So many questions.

[chionomaniac]

Chionomaniac i would not call that a typical canadian warming, to far west. Its certainly further west than the canadian warmings i have read about and the canadian warming in dec of 62.

So many questions.

Yes, it is more like an Alaskan warming! It is difficult to find previous CWs to compare to ( like in the SSW website), but the point I was making was regarding any potential effects it could have had for us downstream in the troposphere.

Interesting further propagation shown by GP earlier. Will we be in the right place to benefit? When comparing the potential vorticity charts that BF posted in he GWO thread a few days ago to the latest output things look ever so slightly more promising.

c

[Guest North Sea Snow Convection]

Looking back to the start of winter and we experienced what I suspect to be a Canadian Warming.

Was this as a consequence of the CW earlier in that month?

I think the warming event over the Canadian arctic towards the end of last year contributed to the very cold US outbreak in Jan and to the zonal pattern we saw during the mid to latter period of Jan. At the time I likened it to Jan 84 cold zonality although not as cold..

To trace that back earlier - as far as we were concerned I think the initial benefits of the first mountain torque event last Dec which provided the trigger for the negative zonal wind anomalies we saw prior to the cooling of the stratosphere in late Dec was the brief easterly early in Jan and that had also helped provide the Scandi blocking just prior to that with the surface cold off the cold continent.

The main effect of that first moderate warming courtesy of M/T though, happened on the other side of the arctic and is why the US went on to reap the full benefits which manifested itself in the Sascatchiwan Screamer that blasted out of the Canadian arctic and gave parts of the US a freeze (down towards Florida too) but in turn gave us the downstream cool/cold zonal pattern we saw thereafter in Jan as the cold air steepened the gradient as it flooded off the eastern seeboard. This continued until the PNA pattern retrogressed the west coast block into the pacific (at the same time as the MMW was exploding). This then allowed the Scandi High to influence us at the end of Jan, at the same time as the atlantic faded in response to the brief initial 'shock' downwelling from the MMW which gave us the short sharp easterly at the start of this month.

The rest is history, as they say. That's all very simplified but I how see it anyway

Edited February 20, 2009 by North Sea Snow Convection

[chionomaniac]

The rest is history, as they say. That's all very simplified but I how see it anyway

I would say that is a good summing up, thanks, T.

Getting back to the here and now there are more tentative signs of further propagation be it only slight before all the negative zonal wind anomalies in all areas of the stratosphere are returned to westerly in around 10 days time. Without a strong stratospheric vortex a weakened jet and a period without strong Atlantic influence still has to be the favoured option for March.

[tundra]

The GFS operational run must be picking up a signal for downwelling of easterly zonal winds and warming into the troposphere for it to be programming so much high latitude blocking.

A signal that is not as yet being picked up by the ECM model.

[chionomaniac]

The GFS operational run must be picking up a signal for downwelling of easterly zonal winds and warming into the troposphere for it to be programming so much high latitude blocking.

A signal that is not as yet being picked up by the ECM model.

Maybe, but it looks like the GFS is following its 100 hPa vortex positioning forecast, whilst the ECM is following its own.

The GFS has a finger of vortex over Scandinavia and the main vortex over eastern Siberia and another finger elongated over Alaska. Very promising.

The ECM has again the main vortex section over eastern Siberia but with a larger body stretching over the whole of Canada and a little bit of northern Greenland. This isn't quite as conducive to Greenland blocking. However these forecasts fluctuate and we could certainly see one change to more like the other. At this time it is something to keep an eye on. Even if the vortex shape is favourable higher up it doesn't necessarily mean that sightly lower down in the troposphere that the vortex isn't dragged into a different position (think elephant trunk tornado to visualise!).

[damianslaw]

This thread has gone very quiet indeed, is it because the expected effect of the warming event in bringing colder conditions has now vanished? some people were suggesting that the effects could still occur alebit much later than originally anticipated - would like some expert views on this.

The forum in general is exceptionally quiet today indicative of this very dull conditions indeed - model watching this past week has been painfully dull indeed almost wanting raging zonality to resurface at least then there is some action in the synoptics.

[Terminal Moraine]

I suspect the impact of the stratospheric warming has not yet materialised, the delay being due to a lack of downward propogation of the warming. I'll be looking out for things to start happening around March 5th or so.

[bluearmy]

This thread has gone very quiet indeed, is it because the expected effect of the warming event in bringing colder conditions has now vanished? some people were suggesting that the effects could still occur alebit much later than originally anticipated - would like some expert views on this.

The forum in general is exceptionally quiet today indicative of this very dull conditions indeed - model watching this past week has been painfully dull indeed almost wanting raging zonality to resurface at least then there is some action in the synoptics.

GP has commented in another thread on how the warmth is still bottled up in the lower stratosphere/upper troposphere. it may well never propogate down far enough into the lower trop to affect the pressure cells as we see them. need to wait and see. i think the reason the thread has gone quiet is that whatever methods posters have used to anticipate a propogation have failed to verify.