Stratosphere Temperature Watch

[Guest mycroft]

Yes. You will remember it well. January 2009 leading to the early Feb easterly.

thank you for your reply,if it's happened once then it could happen again?

Edited January 20, 2011 by mycroft

[Swave Snow]

thank you for your reply,if it's happened once then it could happen again?

I HOPE SO and better this time if Piers Corbyn is right and Will Hand and BFTP you never know.

[Mark Bayley]

What do we have here... Thats sort of warming I was hoping for! (If it comes off of course, and then if it does theres no guarantee it would deliver something good for us!)

Edited January 21, 2011 by Mark Bayley

[Glacier Point]

Now this is worth following. By day 10 a 50C rise in temps at 10hPa. By the way, does anyone have the Feb 2009 warming archived to compare date and magnitude ?

Projected rise in temperatures is over the other side of the Pole and a displacement of the vortex currently projected so it may not be totally beneficial in terms of bringing cold to NW Europe but could evolve from here.

[chionomaniac]

Now this is worth following. By day 10 a 50C rise in temps at 10hPa. By the way, does anyone have the Feb 2009 warming archived to compare date and magnitude ?

Projected rise in temperatures is over the other side of the Pole and a displacement of the vortex currently projected so it may not be totally beneficial in terms of bringing cold to NW Europe but could evolve from here.

I may have on an old lap top at home.

But don't forget that was a split SSW. If this goes the distance then I favour a displacement due to the wave 1 activity increase this time.

[BLAST FROM THE PAST]

AN SSW is unlikely as there is only ever been one recording of a SSW in a solar min and -QBO winter.

Looking at the 100hPa level the signal is mixed to what happens with the limpet high around the UK. The forecasts suggest that this will still be close to the UK. The 10% chance of the high travelling east has faded.

c

Re the first, isn't a westerly QBO a positive QBO?

Re the second I think the motion is retrogression so HP to move west. Any heights to develop to our NE will be a new HP or part of the Russian HP backing west joining the current HP.

This is a very interesting potential development timing wise?

BFTP

Edited January 21, 2011 by BLAST FROM THE PAST

[beng]

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2009.gif

This gives an idea of what happened in 2009. It was initiall focused between 2 and 10hPa - and reached a peak of over 32c above the norm. I'd be a bit worried though it this one is centred on the other side of the pole.

Edited January 21, 2011 by beng

[chionomaniac]

Re the first, isn't a westerly QBO a positive QBO?

Re the second I think the motion is retrogression so HP to move west. Any heights to develop to our NE will be a new HP or part of the Russian HP backing west joining the current HP.

This is a very interesting potential development timing wise?

BFTP

Yes it is - my mistake - Tiredness! ( Good to see someone reads my posts!)

[chionomaniac]

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2009.gif

This gives an idea of what happened in 2009. It was initiall focused between 2 and 10hPa - and reached a peak of over 32c above the norm. I'd be a bit worried though it this one is centred on the other side of the pole.

If we remember the 2009 warming then it was the one that gave the split to the vortex which created the easterly in early Feb. However from that moment on we were thwarted by an weak upper segment of split vortex that built around Newfoundland and prevented Northern Blocking. This was was thought to be influenced by the La Nina after analysis later on. One of the striking things seen that February was the marked reduction of jet stream winds but no favourable northern blocking!

Latest Gfs charts show considerable pressure on the vortex starting from the top.

We also are seeing the considerable warming forecast at 10 hPa to propagate to 30hPa level- we have not seen that yet this winter.

And dare I suggest a split possible at the 100 hPa level - though not a favourable one at present.

[BLAST FROM THE PAST]

Yes it is - my mistake - Tiredness! ( Good to see someone reads my posts!)

I'm trying to find it but I saw somewhere over Christmas that a moderate to strong La Nina and a weak westerly QBO will in Feb correlate to a general flow bewteen E and N. HP to our northern quadrant and troughing in Southern Scandinavia/Germany region. I can't find it now but I was stunned by that and how it matches my 'view' of Feb.

Anyone help on that?

C, I have a little feeling that I may be one of only two? :smiliz64:

BFTP

[chionomaniac]

Now this is worth following. By day 10 a 50C rise in temps at 10hPa. By the way, does anyone have the Feb 2009 warming archived to compare date and magnitude ?

Projected rise in temperatures is over the other side of the Pole and a displacement of the vortex currently projected so it may not be totally beneficial in terms of bringing cold to NW Europe but could evolve from here.

Sadly, Stewart I gave up saving charts to hard drive around the middle of December that year as it took too long. However I did save these from the end of the season.

c

[nick sussex]

Chiono have you seen this site?

http://www.appmath.columbia.edu/ssws/index.php

It gives a list of SSW events from 1958 to 2002 and you have loads of data and animations that go with it.

Edited January 21, 2011 by nick sussex

[chionomaniac]

Chiono have you seen this site?

http://www.appmath.columbia.edu/ssws/index.php

It gives a list of SSW events from 1958 to 2002 and you have loads of data and animations that go with it.

Yes and I love it sad that I am, Nick! I would like to see more recent SSW's on it but a lot of these have been discussed in the middle atmospheric conferences. I have been through all the SSW's on this site to compare to the last few years projections, If we get close to another I will go through again and try and compare to a previous year.

[Thundery wintry showers]

I note with interest that some of the SSWs did not give rise to particularly cold, snowy or blocked weather across the UK- e.g. 18 Jan 1971, 21 Feb 1989, 15 Dec 1998, 30 Dec 2001, 17 Feb 2002. At the other extreme we have the likes of 28 Jan 1963, 4 Dec 1981 and 1 Jan 1985 which emphatically did.

There's also some mixed ones in there. I remember the unproductive blocked spell following the SSW of 26 Feb 1999- the following fortnight had very extensive northern blocking but a low pressure sat out in the North Sea and kept feeding heavily modified air "up and around" from the SE, limiting the UK to just localised snowfalls.

[chionomaniac]

I note with interest that some of the SSWs did not give rise to particularly cold, snowy or blocked weather across the UK- e.g. 18 Jan 1971, 21 Feb 1989, 15 Dec 1998, 30 Dec 2001, 17 Feb 2002. At the other extreme we have the likes of 28 Jan 1963, 4 Dec 1981 and 1 Jan 1985 which emphatically did.

There's also some mixed ones in there. I remember the unproductive blocked spell following the SSW of 26 Feb 1999- the following fortnight had very extensive northern blocking but a low pressure sat out in the North Sea and kept feeding heavily modified air "up and around" from the SE, limiting the UK to just localised snowfalls.

This goes to show how unpredictable SSW's can be to producing cold in one particular location or to more southern latitudes at all. Studies have shown that on average SSW's will lead to colder weather being seen at latitudes further south but that this is never guaranteed.

TWS, do you know if northern blocking was prevalent in the earlier years where the UK did not benefit ( but that other areas did)? Ie did the Arctic leak cold but not to the UK?

Cheers

c

Edited January 21, 2011 by chionomaniac

[Thundery wintry showers]

I'll have a quick browse through the archives. One downside of the WZ archive is that it doesn't include the other half of the globe, so on occasions when I don't see any high latitude blocking, there could still be some on the other side of the North Pole (as happened earlier this month). Another problem is that when we do get blocking following a SSW event it's hard to tell how much of the blocking is caused by the SSW.

Anyway, the SSWs on that list were followed by the following patterns:

• 31 Jan 1958- increasingly persistent Greenland blocking, prolonged UK cold snowy spell from 24 Feb-22 Mar
  
• 15 Jan 1960- again increasingly persistent Greenland blocking, "west based -ve NAO" snowy interlude from 11 Feb-24 Feb
  
• 28 Jan 1963- continuation of Greenland blocking
  
• 16 Dec 1965- no high latitude blocking, but an upper mid-Atlantic ridge in late December brought Arctic air south
  
• 23 Feb 1966- no high latitude blocking on our side of the pole
  
• 7 Jan 1968- lots of high pressure over Canada, cold northerlies over Europe via Atlantic ridge for about a week afterwards then mild
  
• 28 Nov 1968- a lot of blocking over Scandinavia, cold continental air held out to the east
  
• 13 Mar 1969- extensive northern blocking, cold & cloudy with E winds
  
• 1 Jan 1970- frequent northern blocking and southward input of Arctic air, though only affecting the UK in the first week
  
• 18 Jan 1971- briefly blocked late Jan/early Feb but otherwise a zonal pattern
  
• 19 Mar 1971- very extensive N blocking late March-early April, but Arctic air mostly sent elsewhere
  
• 31 Jan 1973- mid-Atlantic high with periodic northerly outbreaks
  
• 9 Jan 1977- very extensive northern blocking, cold & snowy in the UK early in the period
  
• 22 Feb 1979- mostly zonal until 2nd week March, then turned very blocked indeed, snowy in the UK
  
• 29 Feb 1980- blocked to the NE early to mid March, this block then spread to the NW giving cold spell to the UK
  
• 4 Mar 1981- frequent blocking around Canada/W Greenland, cold air sent out into the Atlantic
  
• 4 Dec 1981- frequent N blocking and exceptional cold December for the UK
  
• 24 Feb 1984- extensive N blocking gradually formed towards mid-March
  
• 1 Jan 1985- extensive N blocking, cold snowy month for UK
  
• 23 Jan 1987- quite blocked in N Atlantic until early February then no blocks on our side of the pole, mid Atlantic block mid Feb
  
• 7 Dec 1987- blocked over Canada for a time but otherwise no pronounced high latitude blocks
  
• 14 Mar 1988- fairly extensive N blocking towards the end of March though not cold in the UK
  
• 21 Feb 1989- no N blocking (although 23-27 Feb 1989 gave the only widespread UK snowfalls of the 1988/89 winter quarter via cold zonality)
  
• 15 Dec 1998- no N blocking
  
• 26 Feb 1999- extensive N blocking for 2 weeks but no major end result for the UK
  
• 20 Mar 2000- persistent Greenland blocking immediately afterwards
  
• 11 Feb 2001- persistent Greenland blocking started around 22 Feb
  
• 30 Dec 2001- no N blocking
  
• 17 Feb 2002- no N blocking, although a few brief attempts at cold zonality over the UK
  

In summary there is a definite bias towards more northern blocking following these SSW events, but there are a good half-dozen which failed to produce any northern blocking of note on our side of the North Pole as well as failing to bring any cold snowy weather of note to the UK.

[chionomaniac]

Thanks Ian. That's great.

At some point I will try and analyse these events stratospheric wise to see which events were the best propagators down to the troposphere. It may be best to look at the events that didn't produce northern blocking first and work out if there was a common theme.

[Weather-history]

Chiono have you seen this site?

http://www.appmath.columbia.edu/ssws/index.php

It gives a list of SSW events from 1958 to 2002 and you have loads of data and animations that go with it.

The 7th December 1987 one is very interesting as the inverse seems to have happened. Blocking was already prevalent and lead to a coldish first half to that December but the SSW seems not to have reinforced the block but instead it sank southwards and it became very mild. Look at the charts, you would have never suspected a SSW event had happened.

Edited January 21, 2011 by Mr_Data

[Weather-history]

This goes to show how unpredictable SSW's can be to producing cold in one particular location or to more southern latitudes at all. Studies have shown that on average SSW's will lead to colder weather being seen at latitudes further south but that this is never guaranteed.

What happens if cold is already present, when a SSW event happens? Maybe that is a question that needs also answering. We are assuming that SSW could turn a mild/average pattern into a cold one. Is it possible that the inverse could happen?

Look at the 9th January 1977 event, the UK was essentially in a cold weather pattern , the December was cold, there was a Greenland high present when the SSW happened. The pattern changed about a week after the SSW event and the second half of that winter was essentially mild.

[chionomaniac]

What happens if cold is already present, when a SSW event happens? Maybe that is a question that needs also answering. We are assuming that SSW could turn a mild/average pattern into a cold one. Is it possible that the inverse could happen?

Look at the 9th January 1977 event, the UK was essentially in a cold weather pattern , the December was cold, there was a Greenland high present when the SSW happened. The pattern changed about a week after the SSW event and the second half of that winter was essentially mild.

It is a good question Mr D. It is already recognised as well that there are a series of blocking precursor conditions that are seen prior to SSW's. So in fact SSW's are more likely to be seen in blocked winters than not. In fact these blocking episodes have been well documented and assist in the wave breaking into the stratosphere that cause the warming that leads to a SSW. So there can be a thought that blocking can lead to more blocking later down the line through the assistance of a stratospheric feedback mechanism.

Having said that it is not always the case as 1977 shows.

[Thundery wintry showers]

Look at the 9th January 1977 event, the UK was essentially in a cold weather pattern , the December was cold, there was a Greenland high present when the SSW happened. The pattern changed about a week after the SSW event and the second half of that winter was essentially mild.

Although the cold and snow over the UK declined about a week later, the northern blocking remained pretty extensive for a long while afterwards- just not in such favourable positions to bring cold and snow to Britain:

http://www.wetterzentrale.de/archive/ra/1977/Rrea00119770129.gif

However the point certainly holds for the later examples on 22 February 1979 and 23 January 1987- both of those saw extensive northern blocking vanish about a week after the SSW event.

Edited January 22, 2011 by Thundery wintry showers

[chionomaniac]

The warming forecast from the ECM has reduced a little in intensity this morning. No sign of a SSW just yet.

[Glacier Point]

The disturbances associated with the rise in temperatures over the other side of the Hemisphere appear to be adversely impacting the polar vortex..

ECM middle stratosphere modelling for the polar vortex day 10:

If ever there was a signal for continued ridges at mid latitudes, that is it.

[UV-RAY]

It is a good question Mr D. It is already recognised as well that there are a series of blocking precursor conditions that are seen prior to SSW's. So in fact SSW's are more likely to be seen in blocked winters than not. In fact these blocking episodes have been well documented and assist in the wave breaking into the stratosphere that cause the warming that leads to a SSW. So there can be a thought that blocking can lead to more blocking later down the line through the assistance of a stratospheric feedback mechanism.

Having said that it is not always the case as 1977 shows.

What I would like to know is, which comes first the blocking or the SSW. Too my untrained eye, it appears we need blocking in place for a SSW event to take place?

[cooling climate]

The disturbances associated with the rise in temperatures over the other side of the Hemisphere appear to be adversely impacting the polar vortex..

ECM middle stratosphere modelling for the polar vortex day 10:

If ever there was a signal for continued ridges at mid latitudes, that is it.

Wind that on two or three days and I think it would look a lot more conducive for a more - AO

and blocking to the north, northwest with the vortex back over on the eastern side.