Stratosphere Temperature Watch 2011/2012

[coldwinter]

So perhaps an SSW sooner than expected? Also how long do you think it would take the SSW to start effect the troposphere, under 2 weeks?

Many thanks, Ryan.

[Kentish Kiwi]

Is there any chance the increased amplification and hints of retrogression towards Greenland shown on the GFS 06z and now the ECM 12z could be the models picking up on the effects of the current warming taking place? Or, more excitingly, could it be the models picking up a signal for a SSW pre-cursor blocking event, given the chart Chio posted above?

Edited December 18, 2011 by Kentish Kiwi

[chris55]

Hi guys I very rarely post on Net weather but I do find the whole Strat warming thing very interesting and have very much enjoyed reading through this thread, some great info.

I thought I'd just add in a few links for the benefit of those (like me) who don't fully understand the subject to well. Now the forecasting of a SSW is beyond me, but I find this page excellent for monitoring a SSW when it happens and to see if it's propagating down through the atmosphere.

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/

Back in Jan 2009 we had a major SSW that rapidly propagated down to 30hpa and had a big influence on our weather. You can see the SSW event and the following propagation well on this chart. Note how the temp goes from very cold (white) to much less cold (greens) and nearly off the scale at the 1hpa level. This is a great example of what a SSW looks like on these charts.

After this warming a much more blocked pattern took hold

http://www.wetterzentrale.de/pics/archive/ra/2009/Rrea00120090203.gif

Again in 2010, and although this warming wasn't as dramatic as 2009, nor did it propagate down so well or fast it still had a big impact on the blocking patterns.

Following blocking

http://www.wetterzentrale.de/pics/archive/ra/2010/Rrea00120100217.gif

Now this year we have not seen a SSW that has propagated down to 30hpa and in turn have not seen any really blocked patterns in the winter period (last Jan and Feb included)

So I am hoping to see some more SSW appearing in these charts as we move through winter, and after reading through this thread I am hopeful we may be heading in that direction!.

And there is also the question how much influence these SSW actually have on our weather. But as a novice ut seems to me they do.

(BTW how do I get those pics small?)

[chionomaniac]

Hi TobyT, coldwinter and chris55.

We are still a long way away from a SSW so I wouldn't get too excited yet .

Chris, those charts are useful for post event analysis, but for predicting a SSW we need to look elsewhere. Also they have limitations in that they do not show vortex positions etc. They do show he number of upper strat warmings that do not affect the lower stratosphere or troposphere though.

[coldwinter]

Thanks C.

Ryan.

[BLAST FROM THE PAST]

This is building towards a shot at a very cold spell for January...and I don't mean end of January either. I think we'll see models showing real signs of this come Christmas week.

BFTP

[phil nw.]

Hi TobyT, coldwinter and chris55.

We are still a long way away from a SSW so I wouldn't get too excited yet .

Chris, those charts are useful for post event analysis, but for predicting a SSW we need to look elsewhere. Also they have limitations in that they do not show vortex positions etc. They do show he number of upper strat warmings that do not affect the lower stratosphere or troposphere though.

Am i right in thinking Ed that the potential warming just starting to show is a top down wavebreaking event from tropical/mountain torques rather that a SSW which is an upwelling event of which there`s no sign yet?

[A Winter's Tale]

This is building towards a shot at a very cold spell for January...and I don't mean end of January either. I think we'll see models showing real signs of this come Christmas week.

BFTP

Well Santa may not bring us a White Xmas this year, but come the big day we may find that the models have unwrapped a mighty present.

[SnowObsessor90]

As others have said very interesting and informative thread this, kudos to all those involved.

Think I'm going to be keeping a very close eye on events unfolding here because as we all know not really much at all to look forward too in the immediate term future.

Edited December 19, 2011 by Anonymous21

[chiller]

Hi Folks,

Very interesting thread here as always. I can’t pretend to understand the finer details but it has certainly made me think how the stratosphere affects our weather particularly in the winter months. It made me consider and wonder what the stratosphere was doing during some of the memorable winters past. I located a report detailing a very sudden and explosive SSW in January 1963 and I was surprised the SSW was in mid Jan as I believe this winter began to bite hard from Boxing day which would suggest synoptics had fallen in to place to deliver brutal cold without the SSW being present at the time it began. I don’t have enough experience to comment on this alignment but I find it interesting as it is now possible that we may get a SSW in Jan if things progress favourably.

The article is quite interesting (fairly intense) but if anyone is interested here's the link: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1965)022%3C0597%3AASOAED%3E2.0.CO%3B2

[chionomaniac]

This is building towards a shot at a very cold spell for January...and I don't mean end of January either. I think we'll see models showing real signs of this come Christmas week.

BFTP

Perhaps, perhaps not. Far too early to suggest that type of confidence, Fred.

Am i right in thinking Ed that the potential warming just starting to show is a top down wavebreaking event from tropical/mountain torques rather that a SSW which is an upwelling event of which there`s no sign yet?

No, not necessarily Phil. SSW's as far as I understand can be either remote or local - as can waves that cause minor warmings - and that is all we have forecast yet.

Still another promising ECM this morning keeping yesterdays theme. The polar vortex is coming under pressure.

As of yet I can not see this being picked up in tropospheric output other than slight positioning effects of the PV, so I do not expect major blocking to show on runs.

Edited December 19, 2011 by chionomaniac

[karyo]

This is the best I've seen this look at the 10hpa level and at long last the 30hpa is showing signs of warming too.

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

When I say best, I mean for this year.

Karyo

Edited December 19, 2011 by karyo

[BLAST FROM THE PAST]

Perhaps, perhaps not. Far too early to suggest that type of confidence, Fred.

As of yet I can not see this being picked up in tropospheric output other than slight positioning effects of the PV, so I do not expect major blocking to show on runs.

You know me Ed :smiliz19: , however building towards a 'shot'.... my way of saying improving chances here of possibilities of this. But one has to say a development so soon that didn't seem apparent not so long ago.

Agreed too early for any real major blocking to show on runs as I think it'll be Christmas week models that will show this IF we continue on this path.

BFTP

[chris55]

Hi Folks,

Very interesting thread here as always. I can’t pretend to understand the finer details but it has certainly made me think how the stratosphere affects our weather particularly in the winter months. It made me consider and wonder what the stratosphere was doing during some of the memorable winters past. I located a report detailing a very sudden and explosive SSW in January 1963 and I was surprised the SSW was in mid Jan as I believe this winter began to bite hard from Boxing day which would suggest synoptics had fallen in to place to deliver brutal cold without the SSW being present at the time it began. I don’t have enough experience to comment on this alignment but I find it interesting as it is now possible that we may get a SSW in Jan if things progress favourably.

The article is quite interesting (fairly intense) but if anyone is interested here's the link: http://journals.amet...ED%3E2.0.CO%3B2

Hi chiller,

if you look at the 2010 chart I posted you can see that the amazing December 2010 had no strat warming at 30hpa, and we recorded one of the coldest Decembers on record! So it shows that although there seems to be some link between SSW events and cold blocked patterns it's certainly not the only way to get such patterns.

[karyo]

Hi chiller,

if you look at the 2010 chart I posted you can see that the amazing December 2010 had no strat warming at 30hpa, and we recorded one of the coldest Decembers on record! So it shows that although there seems to be some link between SSW events and cold blocked patterns it's certainly not the only way to get such patterns.

However, November 2010 had a warm stratosphere which helped the December events. By December, the stratosphere cooled significantly but it took till January for the effects to be felt on the ground.

Karyo

[Relativistic]

I have read through some recent pages to get a bit more of an idea on the subject and I have made out the following:

1. Rossby waves can travel to the vortex and either penetrate it underneath from the troposphere or over the top of the stratospheric vortex, introducing warmth and causing disruption.

2. Rossby waves can be seen on 500hPa SLP charts as troughs.

3. High snowcover in the NH allows for the suns radiation to be reflected back up into the strat, introducing warmth.

4. Mountain torques are events where the air pressures either side of a mountain range are different, what this means though, I do not know.

The only question I have is; how are MT's and Rossby waves linked?

Any answers would be much appreciated.

Edited December 19, 2011 by 22nov10blast

[chionomaniac]

I have read through some recent pages to get a bit more of an idea on the subject and I have made out the following:

1. Rossby waves can travel to the vortex and either penetrate it underneath from the troposphere or over the top of the stratospheric vortex, introducing warmth and causing disruption.

2. Rossby waves can be seen on 500hPa SLP charts as troughs.

3. High snowcover in the NH allows for the suns radiation to be reflected back up into the strat, introducing warmth.

4. Mountain torques are events where the air pressures either side of a mountain range are different, what this means though, I do not know.

The only question I have is; how are MT's and Rossby waves linked?

Any answers would be much appreciated.

I think that you have a good grip there 22novblast10.

If you imagine Rossby waves traveling from west to east, then these huge systems can be 'stopped' or deflected by large mountain ranges - hence the mountain torques involved.

[Relativistic]

I think that you have a good grip there 22novblast10.

If you imagine Rossby waves traveling from west to east, then these huge systems can be 'stopped' or deflected by large mountain ranges - hence the mountain torques involved.

Thanks, it's good to know I'm getting somewhere!

[johnholmes]

No, not necessarily Phil. SSW's as far as I understand can be either remote or local - as can waves that cause minor warmings - and that is all we have forecast yet.

As of yet I can not see this being picked up in tropospheric output other than slight positioning effects of the PV, so I do not expect major blocking to show on runs.

hi chio

I'm far less clued up on this aspect than you but does not the manner in which the 'warming' if that is what it turns out to be at 30mb, suggest more of a downwelling rather than the start of a SSW?

Also in the little bit I've managed to collate of the winters/Stratospheric warming and any links, a good many of the cold episodes I've come across so far were long before any SSW showed. These seem to occur pretty late in winter, indeed I'm not sure how they and the so called 'final' warming of the winter can be differentiated?

[chionomaniac]

hi chio

I'm far less clued up on this aspect than you but does not the manner in which the 'warming' if that is what it turns out to be at 30mb, suggest more of a downwelling rather than the start of a SSW?

Also in the little bit I've managed to collate of the winters/Stratospheric warming and any links, a good many of the cold episodes I've come across so far were long before any SSW showed. These seem to occur pretty late in winter, indeed I'm not sure how they and the so called 'final' warming of the winter can be differentiated?

SSW's start in some cases as a downwelling wave with warm air introduced into the vortex as the wave propagates. In other cases the warming is insufficient and the downwelling too weak to create a SSW.

Last winter we saw upwelling waves which split from the centre of the troposphere upwards.

What you have recognised John is the number of times that blocking occurs prior to SSW's. As reported earlier in the thread this is very common and is most likely due to initial wave interactions between the troposphere and stratosphere before the SSW occurs. More research needed here.

[Duane S.]

hi chio

I'm far less clued up on this aspect than you but does not the manner in which the 'warming' if that is what it turns out to be at 30mb, suggest more of a downwelling rather than the start of a SSW?

Also in the little bit I've managed to collate of the winters/Stratospheric warming and any links, a good many of the cold episodes I've come across so far were long before any SSW showed. These seem to occur pretty late in winter, indeed I'm not sure how they and the so called 'final' warming of the winter can be differentiated?

Chio may well correct me but I always though a 'final warming' was called such because of its late timing in the winter season meant another warming episode would not be possible until the next winter?

[phil nw.]

hi chio

I'm far less clued up on this aspect than you but does not the manner in which the 'warming' if that is what it turns out to be at 30mb, suggest more of a downwelling rather than the start of a SSW?

Also in the little bit I've managed to collate of the winters/Stratospheric warming and any links, a good many of the cold episodes I've come across so far were long before any SSW showed. These seem to occur pretty late in winter, indeed I'm not sure how they and the so called 'final' warming of the winter can be differentiated?

Chiono will probably clarify on this but.my understanding is that the forecasted warming at the top 1hPa level is initiated by rossby waves and is a downwelling event.

SWW(sudden stratospheric warmings),according to research are- apart from 2 events- instigated by Trophosphoric blocking first and a warming can take place as soon as 5 days after this.(I guess this is where the phrase Sudden Strato.Warming comes from)

This is more of an upwelling event.

The current forecasted warming at the upper level,as i understand things, is therefore not a SSW and if sufficient downwelling does occur we are looking at a longer delay for any effective blocking than from a SSW.

I have heard estimates of 2-6 weeks in the past.

There are signs this downwelling (remember-not a SSW) is starting to show it`s hand at 5hPa

and signs of the this breaking into the strato at 10hPa

Still a way to go to get anything lower down at 30hPa as we are talking around 8 days now even for this wavebreaking at the top to actually manifest itself.

AS Chiono. has said we shouldn`t hang our hat on this as the warming may not get low enough to affect the Trophosphere However even if it does then we should expect a time lag of at least 2-3 weeks imo.

Ed ,if i have any of this wrong please ammend or modify as you see fit--i am only too happy to learn from any mistakes and i don`t wish to misinform anyone.

Edit.

Just saw your post in reply to John -Ed,whilst i was constructing mine whilst you posted.

Anyway i will let my post stand and you respond as you wish,

Cheers,Phil

Edited December 19, 2011 by phil n.warks.

[johnholmes]

What you have recognised John is the number of times that blocking occurs prior to SSW's. As reported earlier in the thread this is very common and is most likely due to initial wave interactions between the troposphere and stratosphere before the SSW occurs. More research needed here.

I'll have another look at 10-12 years I've sifted through so far. What I did was take occasions where the 30mb temperature exceeded by, about I think, 10C, the average or that time of the late autumn/winter period. I listed the approximate date each time.

I then did, for the same years, without looking to see when if any 30mb temperature rise occurred months when the CET was 2C or more below the 1970-1999 I thnik(?) and made a note of those. The I checked the two lots to see if there was any link whether there had been what I termed a significant warming (10C or more above normal) or none. I also checked when what appeared to be a major warming or SSW or, as it often appeared to be, the last major warming of the winter, anytime between mid/late January onwards. Some years it did not occur. All very mixed so far but at least another 50 years to sift through!

I may be doing the wrong thing anyway. But keeping the 2 results separate I hope is stopping any bias I may have one way or the other. With my memory providing its more than a few hours apart and the paper work is hidden I have not the foggiest idea what anything showed.

sorry not got time to correct spelling at the mo!

Edited December 19, 2011 by johnholmes

[tcc]

Very promising looking stratosphere forcast charts this morning

from the ECM site. Again the big question is will this warming

propagate down through the stratosphere.

One thing that is needling me so to speak is that during the last

two years the ECM extended range output correctly forcast the

extensive northern blocking that we saw where as this year the

the ECM longer range output shows no sigh of northern blocking

even through January and beyond.

This could of course be due to the fact that the atmosphere in the

past two years was already pre set for blocking to take place IE

low solar, higher ozone, active MJO and favorable QBO where as

this year the atmosphere is moving into a more favorable phase

where stratosphere warming and then blocking will appear in a

relatively short time frame.

By the way very good discussion you've been having CH over on the

American board.

Hi CC or whoever, which US board is this on?

Cheers!

[sebastiaan1973]

I presume this board http://www.americanwx.com/bb/index.php/forum/20-weather-forecasting-and-discussion/