Stratosphere Temperature Watch

[Anti-Mild]

Interesting stuff there Tamara, and potentially good news for those of us hoping for a weak PV this coming winter. True the Siberian snow cover was poor towards the start of October, but it has since grown significantly and is in much better shape than the corresponding date in 2008.

As has been stated elsewhere on this forum, a lot of factors seem to be in the right place, and if ENSO wasn't an issue I would expect Winter 2009/10 to be a cracker, but El Nino is one hell of a fly in the winter ointment!

It seems bizarre that the nature of our winter is dependent on how warm a particular area of ocean surface gets!

Edited November 1, 2009 by Anti-Mild

[Guest North Sea Snow Convection]

Interesting stuff there Tamara, and potentially good news for those of us hoping for a weak PV this coming winter. True the Siberian snow cover was poor towards the start of October, but it has since grown significantly and is in much better shape than the corresponding date in 2008.

As has been stated elsewhere on this forum, a lot of factors seem to be in the right place, and if ENSO wasn't an issue I would expect Winter 2009/10 to be a cracker, but El Nino is one hell of a fly in the winter ointment!

It seems bizarre that the nature of our winter is dependent on how warm a particular area of ocean surface gets!

If stratospheric temps can keep normal (or above) as we go towards winter, keeping the lid on the strength of the vortex, and the evolving -NAO signature can keep developing then there is every chance of the pressure pattern favouring a continuing development of snow cover and increasing cold pooling to the north east. That would take us into winter ready for the sort of warming event and -AO set-up that these developments (as suggested above) in conjunction with the easterly QBO and solar min that are conduisive for a good warm stratosphere - and hence plenty of cold air available to be advected westwards to the BI

As you say though, the one thing that could spoil things (in spite of all those factors) is the strength and position of the nino. An unfavourable outcome here would mean that the Pacific signal would trump the favourable atlantic and blocking trying to assert to the north east will be unable to back west. We could still get a -NAO but with the jet too strong we could have lows sitting too close in the atlantic steering weather fronts and tropical maritime air at us from the south west and the cold air bottled up over western russia, northern scandinavia and central and eastern europe.

That is the worst outcome though, and plenty of time to go yet

Edited November 1, 2009 by North Sea Snow Convection

[Anti-Mild]

If stratospheric temps can keep normal (or above) as we go towards winter, keeping the lid on the strength of the vortex, and the evolving -NAO signature can keep developing then there is every chance of the pressure pattern favouring a continuing development of snow cover and increasing cold pooling to the north east.

And if the PV is suppressed this may allow greater a greater degree of Westerly extent of the good ole Siberian High, which should cool the continent down, and perhaps enhance snow cover even more, possibly further strengthening a negative AO signal, further weakening the PV, etc.....

As you say, only time will tell. I sure as hell will not attempt a forecast for this winter! Since I joined Netweather almost 5 years ago, and before that the BBC Weather forums, this is the toughest winter to call as it almost all hinges on one highly unpredictable element.

[johnholmes]

I am no expert as I've made clear, but remember one thing-all the predictions on what may happen are just that; forecasts/predictions; every single piece of the jigsaw needs to be in place before a 'cold' winter can occur and remember February 2009.

To me, amateur that I am in lrf matters, there do seem more rather than less signs pointing towards temperatures being at or rather below the winter average. As to precip I really have no idea, nor I suspect does anyone else, possibly even in the major forecast centres, although with all the additional data they collate and their huge number crunchers then their prospects are, and should be, rather better than most others.

[Fozfoster]

Hi c, good to have STW back.

[chionomaniac]

Hi c, good to have STW back.

Cheers foz,

Doors open today at the ECM.

http://strat-www.met.fu-berlin.de/cgi-bin/diagnostics?1

Here is the first chart that I am putting up.

This chart is a cross section of the NH atmosphere from the equator to North Pole. It shows the average winds across the northern hemisphere through all layers of the atmosphere. The blues indicate net easterly flow, the orange net westerly flow. The chart illustrates perfectly the easterly QBO wind. This is seen as as the area of easterly winds (blue) at the equator to 30ºN from around 50 hPa up to 7 hPa. This influences the whole Northern Hemisphere (and southern). The other thing to note is the area of easterly (blue) at tropospheric level (1000 hPa - 200 hPa) between 80ºN and 90ºN (NP). This suggests that the polar vortex is not sitting concentrically around the North Pole.

c

Edit where is chart?????

Found it!

Edited November 2, 2009 by chionomaniac

[chionomaniac]

At this time of year the northern hemisphere stratosphere is cooling rapidly. As this occurs the polar vortex starts to form. This normally occurs as two separate vortices, one over Siberia and one over Canada, that merge over the North Pole with the Siberian vortex being the dominant one. During this early winter phase one type of warming can occur known as a Canadian Warming (CW). It seems in this case a stratospheric Aleutian high can slightly displace the core of the vortex towards Siberia, leading to a weakening of the vortex and slight net warming.

There is some evidence to suggest that this could occur when looking at the forecasts.

Firstly lets look at the temperature profiles at the 50hPa level for T+00 and T+192

T+00

T+192

And the ECM vortex forecast at 30 hPa

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=30&forecast=all

Note the increase in temperatures and reduction in wind speed as the vortex gets slightly displaced

And the ECM graph forecasts for temperature and mean zonal wind

Anything that can disrupt the vortex and prevent the vortex gaining strength even at this early stage is a good thing in my opinion, so a promising start.

I have also looked back over the years and the mean zonal wind speed on easterly QBO years rarely reaches 30m/s at 30hPa during the winter, whereas it rarely doesn't not reach 30m/s during westerly QBO years.

c

[Shunter]

I think your right.However the Warmer waters appear to have extended a little further East recently.

This link shows latest

http://www.cpc.ncep....s-fcsts-web.pdf

Although it`s due to update this coming week.

It has updated now ( 2nd November ) with signals for strengthening in the coming months.

[Altohumorous]

Thanks Ch,

That'll keep me busy for a while.

I find this whole site amazing, a level of knowledge and resources that is fantastic. I think we are all lucky that the internet allows the sharing of such knowledge in a way that even 20 years ago was impossible.

And what it shows me is that the more we know, the less we understand.

Well said!

Thanks Chionomaniac, very interesting and informative. Now if only I can find the correlation between these factors and the sneezing dolphins off the southwest coast, this time next year we could all be millionaires!

[Guest North Sea Snow Convection]

Zonal winds at all levels of the stratosphere are clearly westerly atm - but they are not unduly strong, and the current prediction at the 30mb level is for them to reduce a little further over the next week.

Also we can see no current organisation of the vortex over the North Pole and towards Greenland

Edited November 5, 2009 by North Sea Snow Convection

[johnholmes]

Tamara-may I ask where that chart is from please-is it an open link for anyone-if so can you post it up please?

thanks

[Guest North Sea Snow Convection]

Sorry John, I have problems posting links atm due to a computer glitch, but that comes from the ECM stratosphere/berlin link that ch provided in his introductory post to the thread. Just click on the forecast diagnostics and the range of temperatur/zonal wind anomaly forecasts are available for the next 8 days. Covers all levels of the stratosphere

[johnholmes]

okay tks, I'll go look

[BrickFielder]

http://strat-www.met.fu-berlin.de/cgi-bin/winterdiagnostics

[chionomaniac]

Latest ECM 30 hPa temperature forecast looks promising with a rising temperature still forecast.

Looking at the 100hPa forecast (at T+192) the shape of the lower stratospheric vortex is consistent with pressure rises towards Greenland. It will be interesting to watch from this end whether that occurs.

c

[chionomaniac]

I have just had a look at the GFS forecasts and that is quite a warming forecast at the 30 hPa level. The warming normally precedes the vortex reduction.

T+00

T+240

Canadian Warming???????

[Anti-Mild]

I have just had a look at the GFS forecasts and that is quite a warming forecast at the 30 hPa level. The warming normally precedes the vortex reduction.

T+00

T+240

Canadian Warming???????

This warming seems to be reflected in the time series of 30hPa at the North Pole:

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

It looks encouraging but the same time series showed an anomalously warm stratosphere through much of Autumn 2007, until it suddenly and dramatically flipped to cold almost exactly on the 1st of December

[chionomaniac]

This warming seems to be reflected in the time series of 30hPa at the North Pole:

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

It looks encouraging but the same time series showed an anomalously warm stratosphere through much of Autumn 2007, until it suddenly and dramatically flipped to cold almost exactly on the 1st of December

Hi AM

I have no doubt that the stratosphere will cool dramatically at some point during the winter. The cooling of December 2007 was dramatic but far less than December 2006 a westerly QBO year. We have greater amounts of ozone transported to the pole than 2007, the tropical stratosphere is colder than 2007 - though it is warming and needs to be monitored - and the series of mini autumnal warmings have kept the polar stratosphere warmer than 2007.

We can only be encouraged by what we are seeing presently, however, as you say, when the vortex settles directly over the pole come December, a far different scenario may present itself.

The 10 day forecast at 30 hPa looks very good for a CW - look at the mean zonal winds down to 3.27m/s - close to reversal

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/kiruna09/index.html

c

Edited November 7, 2009 by chionomaniac

[chionomaniac]

The warming seen at the 30hPa level seen presently is very much in line with the east QBO/ low solar minimum thoughts. It will be interesting though to see what occurs at the heart of winter and to see if above average temperatures can be sustained then.

The GFS is still sticking to its guns with a considerable Canadian based warming suggested.

When one looks in the context of what has occurred before we see that the current temperatures at this level are almost as high as has been recorded for this time of year.

If this warming continues as forecast then I expect to see record warmth recorded for this time of year.

Tropically the colder than average stratosphere has shown signs of warming but is still well below average for this time of year. The colder the tropical stratosphere in relation to the polar stratosphere then the smaller the temperature differential between the two and less 'fuel' for the vortex. I don't know how this may affect the Brewer Dobson circulation - GP?

The ECM is still sticking with the idea of this warming but the mean zonal wind reduction at 60ºN is less exaggerated than yesterday.

http://strat-www.met.fu-berlin.de/cgi-bin/times?plot=fluxes&alert=1

Already we have a very interesting start to the stratospheric winter season, which will hopefully hold far more interest in the months to come.

c

[Guest North Sea Snow Convection]

The upper level of the stratosphere at 10mb level is now predicted to warm quite noticeably over the coming days

It can also be seen that the above average temps at the 30mb level persist

[jethro]

Here's an article which I thought may interest some of you:

http://climatechange1.wordpress.com/2009/11/08/the-climate-engine/

It has potential for climate change discussions, can I please ask that those discussions take place here:

[karyo]

The upper level of the stratosphere at 10mb level is now predicted to warm quite noticeably over the coming days

It can also be seen that the above average temps at the 30mb level persist

This looks promising Tamara! This is a significant warming for the time of year (if it hopefully materialises) and quite different to previous Novembers when the stratosphere was generally average to cool.

A good sign at this early stage!

Karyo

[Guest North Sea Snow Convection]

This looks promising Tamara! This is a significant warming for the time of year (if it hopefully materialises) and quite different to previous Novembers when the stratosphere was generally average to cool.

A good sign at this early stage!

Karyo

Yes, looks like a Canadian warming event is on the way This has been showing on both the GFS and ECM 30mb plots for several days now and now also shows over the same area location for the 10mb level.

The warming looks like it is going to be evident down to the lowest levels of the stratosphere as well, so disruption to the vortex is likely for at least a time. As is often the case with Canadian warmings, which tend to be less extensive with shorter vortex disruption than the more major SSW's that occur later in the winter.

Nonetheless a nice start to the winter stratosphere season so far

Zonal wind forecasts are very subdued too.

Edited November 10, 2009 by North Sea Snow Convection

[Solar Cycles]

Here's an article which I thought may interest some of you:

http://climatechange...climate-engine/

It has potential for climate change discussions, can I please ask that those discussions take place here:

http://forum.netweat...6entry1610996

A very interesting read jethro, would like to contribute in the climate forum. But alas I'm still red carded, when does that end by the way?

[Guest North Sea Snow Convection]

Temps still predicted to go well above average at the 10mb level and still the relative warmth at the 30mb level is sustained.

Of course, as I should have mentioned yesterday this doesn't necessarily mean a cold pattern for the UK - but nevertheless, a signicantly warm stratosphere for the time of year cannot be a bad thing at all.

Still time of course for the proper annual cool off right back down, but with the east QBO and solar min on our side, then the potential for good things this winter is very much there in respect of the stratopshere and the implications for the polar vortex and opportunities for blocking.

Edited November 11, 2009 by North Sea Snow Convection