Stratosphere Temperature Watch 2011/2012

[johnholmes]

Indeed. The ecm 32 dayer, which was considered very accurate with regard to the blocking events of the previous two years, was very misleading this year. I recall Matt Hugo referencing it in his tweets, because blocking to the northwest was depicted by it on several occasions.

Ian Brown rightly receives criticism for some of his posts on here, but in saying that he was right when he mentioned several weeks ago that the vortex split this winter might not be favourable for blocking over the UK and Ireland. He cautioned people not to get carried away at the time. So This winter has shown me it's best not to get carried away by t-240 stratosphere profile charts from now on. Also that a split vortex does not guarantee blocking will occur in the right area for us to benefit from, even if some of the models suggest so in late FI.

good to see folk accepting that NO forecast tool is infallible and neither is any forecaster but careful use of ALL the available data necessary for the forecast time scale being issued does make for a higher probability of the forecast being more accurate than one based on one parameter or indeed on output from one model.

Edited February 15, 2012 by johnholmes

[chionomaniac]

Thanks for the positive feedback all. It has been a very interesting year to monitor and as ever I certainly come out of the season with more knowledge than I entered. This year has been the clearest cut so far to demonstrate the how the stratosphere can influence tropospheric weather patterns and it is good to see that those who may not have acknowledged that previously are slowly coming around to realising the important role the stratosphere plays.

Having monitored for a few years now, it appears that the best type of blocking events are created with local wave breaking into the Arctic stratosphere, rather than the remote wave breaking that we have patiently waited for this winter. Even though we did not see a SSW this season, I suspect that the warming was strong enough to have created one, if the EP flux had been more poleward at the critical time. Even without this flux being on board, we still experienced enough propagation of the negative mean zonal winds to allow HLB's to occur in the second half of winter - it was just that the displacement left the resultant vortex position in the worst possible place for a Greenland block - there is always next winter!

Having said that, there will still be opportunities for possible early spring blocking before or if the mean zonal winds increase - but this may depend on a full revolution of the MJO first!

[damianslaw]

Thanks for the positive feedback all. It has been a very interesting year to monitor and as ever I certainly come out of the season with more knowledge than I entered. This year has been the clearest cut so far to demonstrate the how the stratosphere can influence tropospheric weather patterns and it is good to see that those who may not have acknowledged that previously are slowly coming around to realising the important role the stratosphere plays.

Having monitored for a few years now, it appears that the best type of blocking events are created with local wave breaking into the Arctic stratosphere, rather than the remote wave breaking that we have patiently waited for this winter. Even though we did not see a SSW this season, I suspect that the warming was strong enough to have created one, if the EP flux had been more poleward at the critical time. Even without this flux being on board, we still experienced enough propagation of the negative mean zonal winds to allow HLB's to occur in the second half of winter - it was just that the displacement left the resultant vortex position in the worst possible place for a Greenland block - there is always next winter!

Having said that, there will still be opportunities for possible early spring blocking before or if the mean zonal winds increase - but this may depend on a full revolution of the MJO first!

We have been preety lucky in how the strat and PV have behaved in the last 2-3 winters, but our luck ran out this winter.. all the same it has been good following the strat profile and seeing how it has affected northern hemisphere.

Hoping next year we see a much more favourable warmer strat to start the season and perhaps a more neutral NAO/AO and no strong la nina or el nino - alot to ask for, but it is highly unlikely the PV will be half as strong as it was during the first half of this winter and not stuck to greenland like glue as it has been all winter, also I do feel we will be starting the season with a much warmer strat - nothing too warm mind as this is likely to quickly revert to something much colder - the reverse of this winter and what happened in jan 2011. Would be good to know of those winters which started with a relatively warm strat and how the rest of the winter panned out..

[A Winter's Tale]

I believe that it's important that we follow the nature of the stratosphere and the weather in the UK during the rest of this year for next winter's forecasts. A very interesting time coming up.

[Duane S.]

Yep, best thread of the winter again by a country mile.

I think the key to greater understanding (possibly the holy grail) is knowing in certain atmospheric states what role these many different factors play. It seems that what might be a primary driver in some states, appears to become a 'mere' response in other states.

I think that the sheer enormity of the polar vortex that set up so early on meant that, as in the case with this winter, the likelehood of any long last cold spell was reduced right from the off. Case in point, we saw early last winter when after a small early warming led to the vortex being repeatedly ripped apart, displaced and split with relative ease for the next couple of months. Yet much greater warming events this year have indeed played their part in moving the beast but as soon as the intensisty of the warmings tapered off the vortex is back, on other occasions such a warming would likely have left a 'wake' in the atmosphere of much more HLB and a critcally wounded vortex to see us through the rest of the Feb and into March.

[MattH]

Just a final post from me for this particular season but want to echo the sentiments of others in terms of highlighting how interesting and of use this particular thread is both to professionals and amateurs alike. I, personally, haven't been as involved as I would have liked in recent weeks but as ever from a forecasters point of view the 'here and now' weather takes over at times and the cold synoptic's of recent weeks became dominant over continuing to look at the strat conditions for further down the line, if that makes sense.

Clearly a thanks goes to those primarily involved and taking their time to supply the information and analysis, particular praise goes towards Chino etc in terms of the knowledge he brings to this particular subject and how through his posts and links to papers others have learnt and advanced on this developing and exciting area of meteorology.

I'm sure I posted weeks back that I hoped this winter would deliver 'both sides of the coin' and fortunately it has done. What this has produced is a clear example of how important stratospheric changes can be through the course of the winter. Clearly December was an horrendous month for those wanting colder weather but the changes were picked up in late December and we have seen how those changes which were highlighted and discussed have changed the weather down at surface levels at the back end of the winter.

I certainly look forward to heading back over to this thread (or a new one) towards September and October and get involved again. The way these weeks and months fly by it probably won't seem like that long!...or perhaps that's old age having creeping in

Regards to all...Matt.

NB: Sort of plug but anyone wanting to follow the on-going synoptic's and possibilities in the coming months can follow me on twitter @matthugo81

[Glacier Point]

Want to try something here. Based upon the projection of the tropical waves, mountain torques and warming of the stratosphere, to attempt to predict either a strong warming event of potentially early final warming.

This is highly speculative and is really pushing the envelope so hopefully readers will enter into the spirit and we won't see 'this destroys my faith in teleconnections' type response if it goes pear shaped.

The MJO is currently in phase 1 which translates to the western Indian Ocean and Sea of Arabia.

Forecasts indicate with some agreement a high amplitude and eastward propgating wave to develop in the next 15 days. Here is the ECM ensemble forecast which is representative of GFS and UKMO.

I've talked this winter about the similarities with years with strong MJO events in October. For similar years, there is a suggestion of a strong MJO wave to re-emerge in the late winter / early spring period. 1985 is a particulalry good example which saw a monster wave develop all the way through phases 1 through 5 (Indian Ocean and western Pacific).

Sea surface temperatures ahead of the MJO are anomalously warm across the far western Pacific (phase 4 and 5 domain). This may help the development of deep tropical convection.

As the MJO wave moves through the Indian Ocean, it can trigger strong posiitve mountain torques over the Himalayas. Currently very negative, these mountain torques reversing could potentially trigger remote wave breaking and disruption of the polar vortex.

So key timelines to watch for:

- MJO moving through phase 3/4 and developing high amplitude - - 1st March

- Strong positive mountain torques and rapid increase in tendency in relative angular momentum -- 1st - 10th March

- Rapid increase in high and middle stratosphere temperatures -- 12th through 22nd March

- Blocking signatures in the troposphere developing -- 22nd March through 11th April.

[lorenzo]

GP you should stick this in a blog less it get lost as winter tapers out... with this winter not sending a clear Nina signal this will be an interesting evolution to watch.

I am going to be on the lookout for papers on how mountain torques dissipate this year, the gap in Weickmann and Berrys analysis, not sure if this is anywhere near the models yet...

Looking at winter this year from memory the strong Aleutian low was present as a 'classic' warming trigger the HP cell over siberia on occasion developed HP cells at random too - for me these are areas to watch..

[dallas]

GP, I'm guessing that simular events produced something very wintery in 85 then?

[chionomaniac]

It's good to put your thoughts out like this GP and I will follow with interest. I note we are already seeing an increase in stratospheric wave number 1 activity around day 10. What do you think is responsible for this?

Edited February 17, 2012 by chionomaniac

[Weather-history]

- Blocking signatures in the troposphere developing -- 22nd March through 11th April.

Guess when Easter is this year.....

[Don]

Guess when Easter is this year.....

A white Easter this year? Would be a welcome relief IMO after this poor winter, although I appreciate many would rather have springlike weather by then. However, it looks like we're in for some springlike weather next week.

Edited February 17, 2012 by Don

[TEITS]

A white Easter this year? Would be a welcome relief IMO after this poor winter, although I appreciate many would rather have springlike weather by then. However, it looks like we're in for some springlike weather next week.

Must admit im now following this thread to see how much rainfall is likely through spring. What the drought stricken areas don't want is any form of blocking developing.

[BLAST FROM THE PAST]

This trial by GP looks a good thing to watch.....I am far from against teles and again on record I have said GP's LRF is about the best around but Feb has brought RJS right back in it neck and neck IMO. Now re March/April......

MARCH is expected to start out mild but become a "backward" sort of early spring month with returns to wintry patterns later on. The below normal trend may deepen into early April. The warmth of April 2011 may be in contrast to a cold April in 2012 with May the warm month this time.

Quote from RJS LRF and seems to sing from same hymn sheet as GP. Now for those that want to know or see what happened in analogue year 1985...I'll post some charts.......late winter weather with proper winter cold around for Spring...

http://www.wetterzen...00119850316.gif

http://www.wetterzen...00119850318.gif

http://www.wetterzen...00119850319.gif

http://www.wetterzen...00119850321.gif

http://www.wetterzen...00119850323.gif

http://www.wetterzen...00119850324.gif

http://www.wetterzen...00119850327.gif

http://www.wetterzen...00119850409.gif

Block to our east transfers to become an Arctic GHP that would be begged for in Dec/January/Feb hence my 'ironic' if it happens posts re if great blocking were to develop in March [as it is a v good possibilty]. What follows is extract from Britweather re March 1985

1985 Mild early in the month with some rain. There was a cold, snowy spell midmonth, and particuarly snowy over the north at the end of the month. The temperature fell to -15C at Aviemore on the 18th.The maximum was only -2C at Lerwick on the 28th. There was a mild end to the month.

CET of 4.1c

April 85 came in above average but had a colder latter half.

I would like to add though that the AZH has been very 'interfering' this winter and I can't remember seeing that as normally the AZH does become a friend when blocking to the east backs west...this year it utterly spoilt what were incredible cold prospects to our E and NE....astonishing cold and snow...and it could scupper further cold chances...ahh well.

BFTP

Edited February 17, 2012 by BLAST FROM THE PAST

[Eugene]

Thanks GP, very interesting thoughts and backs up my thoughts of some cold blocking patterns in spring in particular April.

Must admit im now following this thread to see how much rainfall is likely through spring. What the drought stricken areas don't want is any form of blocking developing.

April is one of the driest months of the year on average and spring is a dry season so i think you're out of luck, also with GP's thoughts the probability of a colder than average season and drier than average season seems like a high probability, personally looking forward to some nice cool dry weather in the spring to go on long walks in a dry countryside, some hard night time frosts should help and a stronger sun

[Summer Sun]

Must admit im now following this thread to see how much rainfall is likely through spring. What the drought stricken areas don't want is any form of blocking developing.

The met office have said there was only a 15 per cent chance of getting “well-above average†rainfall in the next 10 weeks. Its looking odds on now for drought warnings to be in place at some point this spring I think.

[Cloud 10]

ECM and GFS both forecasting a warming event at the top of the stratosphere in about 7-10 days time,so

interesting to see how (or if) this makes it to the lower levels.

[damianslaw]

A white Easter this year? Would be a welcome relief IMO after this poor winter, although I appreciate many would rather have springlike weather by then. However, it looks like we're in for some springlike weather next week.

Statistically we are more likely to see a white easter than a white christmas especially in the north and more so the earlier the easter - but this year it is quite late again - nowhere near as late as last year but not early which reduces the chances of snow a little bit. However, we have had a long long run of well above average temps since early september - with only the period 28 Jan - 11 Feb being below.. we are overdue a return to at least average temps if not below average temps and also a colder than normal April - been ages since we have seen a cold April - so yes I think there is a high chance of a cold spring overall - but hopefully the cold runs out of steam by early May. We have seen some very warm weather in recent Aprils i.e. 2007 and 2011 which I alwasy say never bodes well for the summer - so we really don't want any warmth in April.

[NoSnowJo]

Paul and Ian will probably go mad but I just want to say what a fantastic thread this is as a newbie I find it fascinating And a neutral thread not mild or cold just facts, keep up the great work folks as chio has said the weather is a amazing subject whether cold,mild or warm the weather Im the uk is fascinating and keeps us Guessing

[Gavin P]

Must admit im now following this thread to see how much rainfall is likely through spring. What the drought stricken areas don't want is any form of blocking developing.

Blocking doesn't necessarily mean dry. Remember what happened in April 1998;

http://www.wetterzentrale.de/archive/ra/1998/Rrea00119980409.gif

As always it depends where the blocking is and how the jet stream responds to that blocking.

[chionomaniac]

We are seeing a forecast warming of the upper stratosphere, which, even though it has cooled since January, it has never reached the depths of December. The forecast warming is not a strong as that seen last month and we will have to see how far it propagates to the middle stratosphere. currently, projections suggest only a minor warming.

With the lower vortex remaining weak, I do not feel that it would take too much upper distubances to create a split. By the time that would possibly occur we will be well out of winter, but it could lead to colder spring outbreaks. It will be interesting to watch what happens in relation to GP's thoughts. It is these types of chain events that shows the tropospheric/ stratospheric interactions that is becoming more accepted as important drivers of the weather patterns experienced.

Here is a link to a recent met office article explaining how the stratosphere influenced the westward shift of the Siberian high.

http://metofficenews.wordpress.com/2012/02/09/whats-bringing-the-cold-weather-to-europe-and-the-uk/

[johnholmes]

We are seeing a forecast warming of the upper stratosphere, which, even though it has cooled since January, it has never reached the depths of December. The forecast warming is not a strong as that seen last month and we will have to see how far it propagates to the middle stratosphere. currently, projections suggest only a minor warming.

With the lower vortex remaining weak, I do not feel that it would take too much upper distubances to create a split. By the time that would possibly occur we will be well out of winter, but it could lead to colder spring outbreaks. It will be interesting to watch what happens in relation to GP's thoughts. It is these types of chain events that shows the tropospheric/ stratospheric interactions that is becoming more accepted as important drivers of the weather patterns experienced.

Here is a link to a recent met office article explaining how the stratosphere influenced the westward shift of the Siberian high.

http://metofficenews...ope-and-the-uk/

good to see our Met O are using up to date ideas for longer term work. Its some decades ago but the monthly outlook they tried for several years in the mid 70's to 80's off and on, used nothing more than changes in the jet stream beneath the Tropopause. No one EVER mentioned, probably because we never even knew then, about what effects the Stratosphere might have on weather at the surface of the earth.

A clear example of the strides forward in understanding the weather, a long way to go but its still a very big stride forward over the last 30 years or so, much of it in the last 10 years.

[Weather-history]

Statistically we are more likely to see a white easter than a white christmas especially in the north and more so the earlier the easter - but this year it is quite late again -.

Not that late, its about average actually, Easter statistically falls around the first week or second week of April more often than outside these dates.

[syed2878]

my thanks goes to chio, gp and some of the other posters. I shal be folowing this thread with interest for next winter and the weather before that. A request to chio or any of u guys if u can give me links to papers where i can read mor about the strat. The papers i red so far from here gave me alot of understanding. syed2878@gmail.com thanks again guys.

[Catacol]

Forgive my very long term inspired question, but if I understand GP correctly he felt as far back as October that he had a sense of the winter to come. Has anyone ever taken a domino approach to this? In other words if the Oct wave and following winter gives rise to the probability (if GP is proven correct [again] ) of a major strat warming in March on the back of another wave then how far down the line can we go? What does this suggest in terms of pattern for the summer, and is it possible even then to give a call on the following autumn and winter?

A daft question I expect... but there must be grogs out there with more time and expertise than I have got who have looked at this. How close are experts to being able to give a 12 month approximate forecast, or do the variables just get too complex to deal with?

Edited February 18, 2012 by Catacol_Highlander