Stratosphere Temperature Watch 2011/2012

[Gavin P]

Probable further strengthening of the polar westerlies in the Pacific and Atlantic in time looks on the cards, and the trend for the shift of the core of the PV towards west of Greenland dropping into Canada looks rock solid to me (as per October winter discussion and winter forecast).

Does dropping the PV into Canda eventually teleconnect to allowing the ridge to build over Scandinavia?

Edited December 1, 2011 by Gavin P

[Glacier Point]

.. eventually yes Gav altough probably a bit too much inertia for it to fully develop until January.

[kold weather]

Looking at the 100hPa stratospheric charts this morning, subtle changes are likely.

From a period of cold zonality the heart of the polar vortex shifts slightly to the west of Greenland. This will leave us more open to milder zonality with the possibility of a warm ridge extension from the Azores over SE areas.

Thats exactly what I've been expecting, if you look through the model thread I've been saying the possible return of a 'Euro' high. Not quite the same set-up aloft but the broad things will be in place. Need to hope like the 06z GFS suggests that it can get far enough north and clear to give us some decent inversions.

[Gavin P]

.. eventually yes Gav altough probably a bit too much inertia for it to fully develop until January.

Thanks.

[chionomaniac]

Thats exactly what I've been expecting, if you look through the model thread I've been saying the possible return of a 'Euro' high. Not quite the same set-up aloft but the broad things will be in place. Need to hope like the 06z GFS suggests that it can get far enough north and clear to give us some decent inversions.

I know that this is what you have suggested, so well picked up - (though it hasn't occurred yet!)

[MattH]

Heck of a run from the GEM this morning, unlikely mind given the environmental conditions at higher latitudes...

http://www.wetterzentrale.de/pics/Rgem1681.gif

http://www.wetterzentrale.de/pics/Rgem1921.gif

http://www.wetterzentrale.de/pics/Rgem2161.gif

http://www.wetterzentrale.de/pics/Rgem2401.gif

Somehow it splits the PV into two primary areas, one across NE Canada and the other across Scandinavia. This then allows for the 'mobile train' to be shut off and as a result ridging within the North Atlantic is sustained in a far greater way than any of the other models show.

A very interesting set of charts and a shame there is no other support for it, as it would introduce a much greater threat of more sustained colder weather across the UK and essentially signal at least a temporary break in the zonal pattern, but again given stratrospheric temperatures and the likes, the PV is extremely strong at the moment and I don't think it will be "broke" as easily as the GEM is showing.

Slim risk, but for us coldies a nice set of charts to see none-the-less.

[Great Plum]

That is a wonderful GEM run...

In all seriousness though, there have been a couple of runs now from a number of models suggesting what the GEM shows... With the current conditions, this just can't happen can it?

[karyo]

The warming that appeared at the 10hpa level yesterday is today also showing at the 30hpa to a lesser extend. However, it's very brief and the temperature drops down to the well below average levels.

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php

Still nice to see no matter how brief.

Karyo

Edited December 2, 2011 by karyo

[chionomaniac]

Heck of a run from the GEM this morning, unlikely mind given the environmental conditions at higher latitudes...

http://www.wetterzen...cs/Rgem1681.gif

http://www.wetterzen...cs/Rgem1921.gif

http://www.wetterzen...cs/Rgem2161.gif

http://www.wetterzen...cs/Rgem2401.gif

Somehow it splits the PV into two primary areas, one across NE Canada and the other across Scandinavia. This then allows for the 'mobile train' to be shut off and as a result ridging within the North Atlantic is sustained in a far greater way than any of the other models show.

A very interesting set of charts and a shame there is no other support for it, as it would introduce a much greater threat of more sustained colder weather across the UK and essentially signal at least a temporary break in the zonal pattern, but again given stratrospheric temperatures and the likes, the PV is extremely strong at the moment and I don't think it will be "broke" as easily as the GEM is showing.

Slim risk, but for us coldies a nice set of charts to see none-the-less.

I just don't know what stratospheric input and weighting the GEM charts have.

All I know is that if the GFS and ECM strat charts are to be believed then there is very little chance of a anything other than an Intermediate Atlantic ridge temporarily extending into Greenland, and that should be quickly squashed by the vortex.

The potential vorticity chart at 380 K from the ecm below shows the area that any pressure rise is indicated - more towards Scandi.

One can see how this is formulated by running through the pv charts (these charts at this level are subject to daily fluctuations).

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ecpv.php?alert=1&level=380&forecast=all&lng=eng

The 100hPa chart at T+240 looks like there is a rock solid barrier to Greenland height rises with the emphasis on the centre of the vortex shifting slightly west of Greenland.

Without support from these charts I cannot see any permanent Greenland height rises coming off.

There is also no evidence of major wave breaking to assist this possibility.

c

[snowmadchrisuk]

Just to add to my previous post another good chart this morning comes from the No Gaps .. Cannon Model I know but you never know .

If this came off the 528 dam would cover the whole UK

[geoffw]

how likely is it a SSW will occur this year?

[MattH]

I just don't know what stratospheric input and weighting the GEM charts have.

All I know is that if the GFS and ECM strat charts are to be believed then there is very little chance of a anything other than an Intermediate Atlantic ridge temporarily extending into Greenland, and that should be quickly squashed by the vortex.

The potential vorticity chart at 380 K from the ecm below shows the area that any pressure rise is indicated - more towards Scandi.

One can see how this is formulated by running through the pv charts (these charts at this level are subject to daily fluctuations).

http://wekuw.met.fu-...ast=all&lng=eng

The 100hPa chart at T+240 looks like there is a rock solid barrier to Greenland height rises with the emphasis on the centre of the vortex shifting slightly west of Greenland.

Without support from these charts I cannot see any permanent Greenland height rises coming off.

There is also no evidence of major wave breaking to assist this possibility.

c

Without sounding like stealing your thunder, this is exactly what I meant, but didn't have the time to advance in as much detail as you have and usually do...

The scenario is far from unexpected and clearly as been discussed in detail here nothing has and will likely change now for the majority of December. Granted as with the coming 7 days if you get a sharp enough trough to the E of the UK or perhaps right over the UK and slight ridging to the W then temporary colder incursions are possible, but the likes of anything substantial look highly unlikely for December. The latest EC 32 is far from inspiring either and essentially paints a "standard" December month...

I've spoke with good'ol Terry Scholey today as well and he's steadfast in thinking that whilst the long term remains highly uncertain, he also feels that the middle and latter half of the winter could well the the coldest, but La Nina may well be an offset. Overall a very difficult winter to forecast and I still believe that a rapid and dramatic change will materialise into January either to be honest. Perhaps you would imagine after such intense cold over the pole things would eventually change and whilst no doubt this is a possibility, not matter how small the odds, it may well not either, especially if the QBO remains easterly through the majority of the winter...

Overall IMO 2011 has to go and will no doubt go down as one of the most boring years weather wise without question. Perhaps others may disagree given regional variability but from January to December there's been a distinct lack of "nothingness" this year to be honest and the again I do believe we have been spoilt almost given the last 2 winters to start with...

Matt.

[BLAST FROM THE PAST]

Hi Matt

I think a fair assessment. I think an overall close to average Dec which in my book will give something for everyone and won't be a plain 'flat pattern' . I personally have eyes on Jan rather than Feb but hopefully a good cross over will occur too. La Nina killed last winter off so one to watch.

BFTP

[snowlover2009]

Am I right in hearing a scandi high above, possibly developing when the PV shifts to the Canada, which can only mean heights towards Greenland or potential of heights to build more frequently or easily. But first we have to get through December? The favourite month for cold with the season of good will etc Of course the current charts suggest cold and snow, but not the proper blocked scenarios we have seen in recent years etc.

[MattH]

In conjunction with yesterday's brilliant 00Z GEM model and also some of the EC ENS members, the 00Z UKMO model is of interest this morning;

http://www.meteociel.eu/ukmo/run/UN120-21.GIF?03-06

http://www.meteociel.eu/ukmo/run/UN144-21.GIF?03-06

Some interesting developments there...

M.

[chionomaniac]

I have seen a few references in the model thread to warm ups of the stratosphere. I can see no warming forecast other than normal fluctuations that one would expect with cold or slightly less cold areas circulating the vortex.

[Cloud 10]

Hopefully,the only way is up!

Monitoring of the Stratospheric Circulation

[geoffw]

i ask AGAIN how likely is a SSW this winter?

[chionomaniac]

i ask AGAIN how likely is a SSW this winter?

No need to shout Geoff!!!

It is difficult to put a figure on how likely a SSW is this year, but there are certain conditions that make SSWs more likely to occur than not in some years compared to others. A lot of them are in place so I would say that a SSW is 60/70% likely.

[geoffw]

thanks

[Kentish Kiwi]

Hopefully,the only way is up!

Monitoring of the Stratospheric Circulation

Doesn't look like it!

[chionomaniac]

Still no significant change in the stratosphere with the temperature in the mid stratosphere running far below average.

There are signs that the heart of the stratospheric vortex may be about to relocate to the Pacific sector following a period in the Atlantic sector.

Both the ECM and GFS suggest this by day 10 at both the 30 hPa and 100 hPa levels.

This tends to occur as part of the normal vortex reactions to wave changes and it is interesting that it is in these phases that if the vortex was weaker or the stratosphere warmer that a splitting would most likely occur. That is very unlikely presently.

If the stretching of the vortex is part of a relocation phase to the Pacific sector it will be interesting to see what could be allowed in the terms of height rises in the Atlantic sector. Too early to say presently.

[stuart mac]

The Stratosphere seems to be around record lows - is there any historic data showing a trend when the stratosphere has been this low?

[phil nw.]

Still no significant change in the stratosphere with the temperature in the mid stratosphere running far below average.

There are signs that the heart of the stratospheric vortex may be about to relocate to the Pacific sector following a period in the Atlantic sector.

Both the ECM and GFS suggest this by day 10 at both the 30 hPa and 100 hPa levels.

This tends to occur as part of the normal vortex reactions to wave changes and it is interesting that it is in these phases that if the vortex was weaker or the stratosphere warmer that a splitting would most likely occur. That is very unlikely presently.

If the stretching of the vortex is part of a relocation phase to the Pacific sector it will be interesting to see what could be allowed in the terms of height rises in the Atlantic sector. Too early to say presently.

I reckon it will tug the jet a little north on the Atlantic side C--likely we will go milder Zonal for a bit if pattern is flat,maybe High pressure closer to the South than currently..

The saviour for coldies is if the jet buckles and allows ridging in the right places-can`t see any northern blocking yet though.

Edited December 5, 2011 by phil n.warks.

[sebastiaan1973]

-9.09 in november at 30hpa, 8.5 at 50hpa

http://www.cpc.ncep.noaa.gov/data/indices/qbo.u50.index

Edited December 6, 2011 by sebastiaan1973