Stratosphere Temperature Watch 2013/2014

[Mapantz]

I just want to say thanks to all those who input in to this special thread. 

 

Quick question..

 

Obviously not all warmings or even sudden ones are guaranteed to bring prolonged cold to the UK?! The last four Winter seasons, we've seen three SSW's (please correct if wrong) - I've managed to see some snowfall from this, even if it has melted the same day! 

Does anyone have any statistics on warmings from 1994 - 2009? The reason I ask is because I barely saw a flake settling in my part of the country in that time, surely there were SSW's or large wave breaks?

 

Regards.

[johnholmes]

this link shows where the basic 30mb temperature is-the lowest I have seen it in 6 or 7 years watching it. As they say the only way is up!

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

[karyo]

this link shows where the basic 30mb temperature is-the lowest I have seen it in 6 or 7 years watching it. As they say the only way is up!

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

This looks rather depressing!

 

On top of that the 18z GFS shows a much stronger vortex than previous runs!

 

Karyo

[bluearmy]

This looks rather depressing!On top of that the 18z GFS shows a much stronger vortex than previous runs!Karyo

One run Karyo, following a run of consistent ones. Keep your powder dry till tomorrow.EDIT: you can come out from behind th sofa now Karyo! Infact, the 00z looks progressive if anything. Word from Ian is that Exeter's 'cold' possibility is not strat led so interesting that the extended ECM ens clustering at week 2 has some viable cold patterns. Nick f alluded to this on the MOD thread a couple days ago.Btw, flux alert on Berlin although want to see more than one forecast. Looks a tad odd? Edited December 30, 2013 by bluearmy

[KTtom]

Good morning . I'm not as educated as you guy's on this subject, but surely this is the chart of the winter so far and will have major implications later in the month?

 

Edited December 30, 2013 by KTtom

[karyo]

Yes, the warming is thankfully back on and where we want it this morning!

But we need to see consistency. Yesterday, we had a brilliant 6z gfs, followed by a slightly less promising 12z and a bad 18z.

 

Karyo

[johnholmes]

One run Karyo, following a run of consistent ones. Keep your powder dry till tomorrow.EDIT: you can come out from behind th sofa now Karyo! Infact, the 00z looks progressive if anything. Word from Ian is that Exeter's 'cold' possibility is not strat led so interesting that the extended ECM ens clustering at week 2 has some viable cold patterns. Nick f alluded to this on the MOD thread a couple days ago.Btw, flux alert on Berlin although want to see more than one forecast. Looks a tad odd?

 

but the basic chart I showed was not a one off

[karyo]

but the basic chart I showed was not a one off

Yes, that chart shows that the temperatures over the pole have continued to drop despite the Asian warming. If the 0z gfs is correct, even those temperatures should start to recover by the 2nd week of January.

 

Karyo

[snowking]

Very encouraging output from the GFS and ECMWF this morning.

 

Just as Wave 1 is forecast to tone down a little:

 

 

Wave 2 strengthens once again:

 

 

For those asking the other day what the difference between a wave 1 and wave 2 attack actually looked like, well here's a pretty clear wave 2 forecast from day 10 at 10mb:

 

 

 

You can see pressure being placed on the vortex from two different areas (hence wave 2) and squeezing the vortex in the middle in to that sort of monkey-nut type shape:

 

 

(for those unsure of what a monkey nut is)

 

 

This is why wave 2 activity is more likely to lead to a split in the vortex as the two waves attempt to slice through the middle of the vortex, where as wave 1 often leads to a displaced vortex because pressure is being placed on it from just 1 side - like pushing a box across the floor.

 

The most encouraging thing, whilst timing may differ somewhat, is that both the GFS and ECMWF are showing similar setups towards days 10-15. Taking 30mb as an example:

 

 

Very encouraging overall, though as BA says above we now need to see this become a consistent forecast.

 

SK

Edited December 30, 2013 by snowking

[MattH]

Well hello....

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f240.gif - Renewed wave 2 activity from the ECM by day 10 and at a somewhat lower level as well

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha1_f240.gif - Wave 1 still loitering about above 10hPa in particular

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_u_f240.gif - Compared with the >90m/s values of late, that's definitely a reduction, clearly NOT a SSW though for the record.

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/fluxes.gif - Something a little odd going on with the EPV direction, still not directed at the pole.

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf30f240.gif - Signs at various levels above 30hPa of a possible split. Think this tallies in with yesterdays 06Z GFS run I think it was. I'm skeptical over this mind at that range given the strength of the vortex, but if a split can be achieved now what a massive bonus that would be, especially if additional "attacks" of wave 1 and 2 continue through January.

 

Interesting times....

 

Matt.

[Cecil Hogmanay Melchett]

Well hello....

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f240.gif - Renewed wave 2 activity from the ECM by day 10 and at a somewhat lower level as well

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha1_f240.gif - Wave 1 still loitering about above 10hPa in particular

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_u_f240.gif - Compared with the >90m/s values of late, that's definitely a reduction, clearly NOT a SSW though for the record.

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/fluxes.gif - Something a little odd going on with the EPV direction, still not directed at the pole.

 

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf30f240.gif - Signs at various levels above 30hPa of a possible split. Think this tallies in with yesterdays 06Z GFS run I think it was. I'm skeptical over this mind at that range given the strength of the vortex, but if a split can be achieved now what a massive bonus that would be, especially if additional "attacks" of wave 1 and 2 continue through January.

 

Interesting times....

 

Matt.

Cheers matt,

Im sure all the coldies are praying that something gives soon with this vortex.If there was ever a doubt about the relationship between a cold strat and a deep entrenched PV i think December has blown that doubt out of the water!

[Duane S.]

Snowking and Matt summing up this morning's Berlin forecasts very concisely! An intense vortex under attack, more wave attacks very likely into January with increasing support of a warming of sorts as well. It will make for some fascinating Stratosphere chart watching over the next few weeks I reckon.

 

The EPV forecast of D9 and 10 looks a bit bizarre though?

 

If not erroneous, what would be the net result of that? Shame it didn't move 90 degrees 'clockwise'...

[lorenzo]

Here is some re-analysis of previous SSWs - the central dates are from the Martineau site for convenience, also where you can view  the linked animations, rather than go back to historic years have just picked from 2006 onwards wrt thoughts that this is where climatology shifts and recent winters have been 'different'.

 

The Idea for the zonal wind time latitude series came from GP post in last years thread where he compared the zonal wind profile against 1968,  the heights to look at pre-cursors. The date display on the zonal wind is a little weird to read, starts with year / month / then days are in chunks of 10. i.e 00 / 10 / 20 / 30.

 

December 2013 for comparison with this season vs. previous.

 

17/01/2013 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2013_01_17.gif

 

17/01/2012 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2012_01_17.gif

 

30/01/2010 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2010_01_30.gif

 

28/01/2009 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2009_01_28.gif

 

24/02/2008 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2008_02_24.gif

 

26/02/2007 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2007_02_26.gif

 

24/01/2006 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2006_01_24.gif

 

[sebastiaan1973]

@ Lorenzo, is it in  your opinion coincidence we have since 2006 (except 1 year) every year a SSW?

Once again quite an impressive warming on both sides.

 

[cooling climate]

The warming shown on the strat charts taken from instant weather maps for

the 1mb level on the 06z GFS run now show the warming right over the pole.

[lorenzo]

Different posters have put up the 500hPa anomaly plots for the last 5 years then also compared with the previous decade and there are clear differences in the established patterns. Whether these can directly be attributed to increased SSW I really don't know, I guess we will need to look back at that once there is a larger dataset.  I was really just thinking about what I had saw in these plots combined with the fact that we are having colder and snowier winters of late. The following post has some more reading re: links into Arctic Sea Ice as does the most recent Cohen paper on Warm Ocean / Cold Continents.

 

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/12/24/arctic-warming-jet-stream-coupling-may-portend-another-winter-of-extreme-storms-and-cold-air-outbreaks/

[Snowy L]

One run Karyo, following a run of consistent ones. Keep your powder dry till tomorrow.EDIT: you can come out from behind th sofa now Karyo! Infact, the 00z looks progressive if anything. Word from Ian is that Exeter's 'cold' possibility is not strat led so interesting that the extended ECM ens clustering at week 2 has some viable cold patterns. Nick f alluded to this on the MOD thread a couple days ago.Btw, flux alert on Berlin although want to see more than one forecast. Looks a tad odd?

Just a guess but could the cold signal be because of tropospheric precursors to an SSW? If I remember right a strong scandi/siberian high, which is what we are seeing on the charts, is a known precursor for both wave-1 and wave-2 lead SSWs, particularly wave-1.

Edited December 30, 2013 by Snowy L

[Recretos]

After long 6 days, the Telecom people finally came around and repaired my modem. I had internet on my smartphone, but I was already over the data transfer limit.

 

I will get straight to the point since I am low on time. SK and Matt have nicely summed the EC forecast, so I will be a bit unconventional again and just quickly present some basic plots. 

 

The most aggressive output is from the GEFS Control run this morning. Even the bias corrected version isn't that bad. It is pressuring quite hard, which can also be noted on the zonal mean zonal wind graph. 

 

 

 

  

 

GFS 6z isnt bad either. Greatly reduced polar night jet, with negative zonal mean zonal wind slowly approaching that notorious 60N threshold level.

 

 

 

Vortex is almost beyond the point of return at 1mb in the 6z GFS. Emphasis on the "almost".

 

 

On 10mb it is also struggling but after all that is going to hit it up to that point, I guess that it wont take that much more before it says "thats it, im out". Tho this is just a forecast, as I always try to emphasise.

 

 

Nice graphics from @Lorenzo' previous post. I will try to gather the data, and make precursor pattern climatologies. Tho we have seen quite a few of them already, I will try to make it with my "new graphics" and we can perhaps store them somewhere on the netweather,tv domain for future reference. This would take much less effort than the GWO composites, since the amount of data-to-gather is like 1000x smaller.

 

Best regards.

Edited December 30, 2013 by Recretos

[lorenzo]

Re: Ed mentioning the VI period ending, that brown blob at the top of this chart is receding..

 

Think the MJO is the guilty party in relation to the GEFS Control Run, high amplitude phase 6.

 

 

Out of kilter with the other projections.

 

GWO cycles round to frictional > Mountain Torque after 10 days...

 

Will we get the EAMT ?

 

 

 

 

 

[Catacol]

Here is some re-analysis of previous SSWs - the central dates are from the Martineau site for convenience, also where you can view  the linked animations, rather than go back to historic years have just picked from 2006 onwards wrt thoughts that this is where climatology shifts and recent winters have been 'different'.

 

The Idea for the zonal wind time latitude series came from GP post in last years thread where he compared the zonal wind profile against 1968,  the heights to look at pre-cursors. The date display on the zonal wind is a little weird to read, starts with year / month / then days are in chunks of 10. i.e 00 / 10 / 20 / 30.

 

December 2013 for comparison with this season vs. previous.

December 2013.gifZonal Wind 2013.gif

 

17/01/2013 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2013_01_17.gif

SSW 17th January 2013.gifSSW 17th January 2013 Zonal Wind.gif

 

17/01/2012 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2012_01_17.gif

SSW 17th January 2012.gifSSW 17th January 2012 Zonal Wind.gif

 

30/01/2010 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2010_01_30.gif

SSW 30th January 2010.gifSSW 30th January 2010 Zonal Wind.gif

 

28/01/2009 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2009_01_28.gif

SSW 28th January 2009.gifSSW 28th January 2009 Zonal Wind.gif

 

24/02/2008 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2008_02_24.gif

SSW 23rd February 2008.gifSSW 23rd February 2008 Zonal Wind.gif

 

26/02/2007 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2007_02_26.gif

SSW 26th February 2007.gifSSW 26th February 2007 Zonal Wind.gif

 

24/01/2006 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2006_01_24.gif

SSW 24th January 2006.gifSSW 24th January 2006 Zonal Wind.gif

 

Struggling to see a pattern here. Every example looks different to me - so what's the conclusion?

 

The concept of tropospheric precursors to warming events still fascinates me but I am yet to find a clear and concise analysis of them. There is a definite gap in the market.

Edited December 30, 2013 by Catacol_Highlander

[snowking]

As ever a terrific post from Recretos showing us even more data pointing in a similar direction.

 

Just to show those who are perhaps new to stratospheric monitoring why we are excited about what is forecast (worth bearing in mind this is still quite a long range forecast) to be happening 30 miles above our heads. At the moment we can see from the Northern Hemisphere 500mb plot that we have two main segments to the polar vortex (the larger purple blobs), one over Siberia and the one I have circled that's proving crucial to our current setup over E Canada/W Greenland:

 

 

If we look even out to T+384 at the lowest level of the stratosphere, 100mb, it becomes apparent why this current pattern is with us. Whilst we have a split in the energy of the vortex, one of the core areas of energy is still over that E Canada/W Greenland area, as shown below:

 

 

But if we look higher up the stratosphere, at say 10mb these areas of the vortex are in slightly different positions, moving away from Greenland:

 

 

And then looking right up to the top of the stratosphere, it moves even further away:

 

 

So that's all well and good but why does it look exciting? Well what's actually (hopefully!) happening is the pattern from the top of the stratosphere is downwelling (moving down the atmosphere). If it were to continue to downwell in to the troposphere then we would see the remaining vortex energy to our North-West retreating Westwards away from Greenland and potentially opening that area up to some higher heights and ridging. This is still all a long way away but that's what we are now looking for as a minimum. A more optimistic view would be that we see the total disintegration of the vortex from the top downwards.

 

We are already seeing this downwelling occur in the latter stages of model runs as the split occurs at 1mb and translates down to 10mb further down the line, along with the position of each of the segments of the vortex. If that can carry all the way down to the surface, then things are looking much better as we head in to the second half of January and more especially February.

 

SK

[marksp]

thank you snowking for an excellent post, this thread is fascinating and your explanation was a great way to show what could happen.

 

cheers  

[johnholmes]

sorry to clutter the thread when simply commenting on this. A nice explanation of what is showing and what may happen-thanks for that SK, it should be very helpful to those either new to this branch of meteorology or still confused by it, me being in the latter area!

[Norway Nut]

As ever a terrific post from Recretos showing us even more data pointing in a similar direction.

 

Just to show those who are perhaps new to stratospheric monitoring why we are excited about what is forecast (worth bearing in mind this is still quite a long range forecast) to be happening 30 miles above our heads. At the moment we can see from the Northern Hemisphere 500mb plot that we have two main segments to the polar vortex (the larger purple blobs), one over Siberia and the one I have circled that's proving crucial to our current setup over E Canada/W Greenland:

 

500mbvortex.png

 

If we look even out to T+384 at the lowest level of the stratosphere, 100mb, it becomes apparent why this current pattern is with us. Whilst we have a split in the energy of the vortex, one of the core areas of energy is still over that E Canada/W Greenland area, as shown below:

 

100mbvortex.png

 

But if we look higher up the stratosphere, at say 10mb these areas of the vortex are in slightly different positions, moving away from Greenland:

 

10mbvortex.png

 

And then looking right up to the top of the stratosphere, it moves even further away:

 

1mbvortex.png

 

So that's all well and good but why does it look exciting? Well what's actually (hopefully!) happening is the pattern from the top of the stratosphere is downwelling (moving down the atmosphere). If it were to continue to downwell in to the troposphere then we would see the remaining vortex energy to our North-West retreating Westwards away from Greenland and potentially opening that area up to some higher heights and ridging. This is still all a long way away but that's what we are now looking for as a minimum. A more optimistic view would be that we see the total disintegration of the vortex from the top downwards.

 

We are already seeing this downwelling occur in the latter stages of model runs as the split occurs at 1mb and translates down to 10mb further down the line, along with the position of each of the segments of the vortex. If that can carry all the way down to the surface, then things are looking much better as we head in to the second half of January and more especially February.

 

SK

Ok, in simple terms the Strat vortex is like what you see when you let the water go down the plug hole. You will notice that the vortex is never straight up and down ( well rarely) and in the bath the exit hole is fixed.  Now in the strat vortex, am I right in saying that you are expecting the vortex to straighten out because the top of the vortex is not over the bottom of the vortex and that the top of the vortex drives the bottom and not vice versa?

[Interitus]

The warming shown on the strat charts taken from instant weather maps for

the 1mb level on the 06z GFS run now show the warming right over the pole.

1mb 30.12.13.gif

 

Well if the last couple of GFS runs come to fruition we have a full-on warming into the third week of January leading to a classic vortex split which should translate into affecting troposphere AO about a week later i.e last week of January and into start of February with maybe a typical 'horseshoe' shape pressure pattern of low pressure round the pole with high pressure from the north Atlantic to the pole as mentioned by SK.

 

Struggling to see a pattern here. Every example looks different to me - so what's the conclusion?

 

The concept of tropospheric precursors to warming events still fascinates me but I am yet to find a clear and concise analysis of them. There is a definite gap in the market.

 

There are quite a few papers that look at some tropospheric precursors, but as they typically build on analogues they do tend to be quite vague when trying to forecast from actual conditions.

What is interesting and may be indicative is trying to figure out if a 'tipping point' can be derived from stratospheric data and the relationship between phases of vortex intensification and subsequent vortex instability when a warming and vortex weakening occurs. From looking at the data as the vortex increases in strength and after a short lag period (~roughly a week) the waves also tend to increase in strength, which in turn can further strengthen or decrease windspeed and so on. This feedback normally cycles until a point where the vortex is in a position that leads to its own demise.

Just a quick look at the wave activity we are seeing on the Berlin ECMWF charts - the average 60°N 10mb total geopotential wave (wave 1 + 2) for January is about 1695, so the forecasts are not much above average. If we look at the MERRA data for January SSW - reversed 60°N 10mb zonal wind then the average 14 day GP wave prior to these events is 1837 so we are looking to be around the ballpark figure.

However, the figures vary such that low wind speeds tend to have a lower average wave, but then also seem only to require a lower wave to collapse. So the lowest was 1512 in 2006 but the highest windspeed in the previous fortnight was only 17 m/s, whereas 2009 had an average wave of 2179 but the highest wind in the previous 14 days was a very healthy 67 m/s.

It's not as simple as purely looking at extreme wave values as they don't always lead to SSW, but they do tend to be followed by weakened vortices. The second highest combined values peaking at 2882 were in January 1986 with wind speeds peaking above 59 m/s but resulted in no SSW so wouldn't feature in a rudimentary analysis. There was though a warming and large reduction in strength throughout the vortex which was followed by a tropospheric AO of -2.9 in February with the 5th lowest CET of -1.1°C

Edited December 30, 2013 by Interitus