Stratosphere Temperature Watch 2015/2016

[Walsall Wood Snow]

2 hours ago, CreweCold said:

Does any of the more learned on here know how any warming is likely to manifest i.e would we be looking at a fairly rapid trop response or are we going to be waiting around? I only ask because I don't fancy using up the best (first half) part of January waiting for any effects to be felt. February cold is never the same in my opinion.

February can be a severely cold month though. What about February 1947 which was one of the most famously cold months of the 20th century. Also February 1986 which was the last sub zero CET month before December 2010 and also February 1991 which was very cold and snowy in the first half at least. Not to mention that we can get deep cold post February like in March 2013 and that was late March. In fact i've heard statistically February is the coldest month of the year on average if not joint coldest or at least second coldest after January but probably little warmer than its preceding month.

Edited December 11, 2015 by Walsall Wood Snow

[Ruben Amsterdam]

In Holland we have the famous Elfstedentocht, a 200km ice skating tour/competition. It has been held 15 times since 1904, most often in February but only once in December (1933). So yes, February can produce extreme cold when the continent is snow covered and SSTs are at their lowest...

[Nouska]

55 minutes ago, Walsall Wood Snow said:

February can be a severely cold month though. What about February 1947 which was one of the most famously cold months of the 20th century. Also February 1986 which was the last sub zero CET month before December 2010 and also February 1991 which was very cold and snowy in the first half at least. Not to mention that we can get deep cold post February like in March 2013 and that was late March. In fact i've heard statistically February is the coldest month of the year on average if not joint coldest or at least second coldest after January but probably little warmer than its preceding month.

February 1947 . . . . now, that would have been an exciting time to be watching stratospheric developments.

[Nick F]

6 hours ago, CreweCold said:

Does any of the more learned on here know how any warming is likely to manifest i.e would we be looking at a fairly rapid trop response or are we going to be waiting around? I only ask because I don't fancy using up the best (first half) part of January waiting for any effects to be felt. February cold is never the same in my opinion.

Some previous strat warming events saw the tropospheric pattern change (i.e. blocking) before the official stratospheric vortex split or displacement. The 1986-87 winter featured a strong El Nino, the strat vortex displacement didn't officially occur until Jan 25th '87' but the infamous brutal cold easterly started early on in the month. Check out this strat loop here:

http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1987_01_25

Current ECMWF and GFS runs both indicating impressive  strat warming over eastern Siberia from about day 5 onwards, which could help nudge the strong PV at least in the meantime. Also I'm encouraged by the increasing wave number 1 EP flux by Berlin strat forecasts by day 10, also wave number 2 EP flux evident via Euro ridging ... which should continue to put pressure on the vortex.

I guess with the strong El Niño with typical Dec climo it brings and the more amplified MJO signal now forecast, the pattern for the rest of this month may remain unfavourable for blocking. But the consistent wave flux signals from the models suggest energy transfer to the strat will continue unabated and will hopefully lead to a weakening in the New Year ... fingers crossed not too much of a wait!

Edited December 12, 2015 by Nick F

[Cheshire Freeze]

2 minutes ago, Nick F said:

Some previous strat warming events saw the tropospheric pattern change (i.e. blocking) before the official stratospheric vortex split or displacement. The 1986-87 winter featured a strong El Nino, the strat vortex displacement didn't officially occur until Jan 25th '87' but the infamous brutal cold easterly started early on in the month. Check out this strat loop here:

http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1987_01_25

Current ECMWF and GFS runs both indicating impressive  strat warming over eastern Siberia from about day 5 onwards, which could help dudge the strong PV at least in the meantime. Also I'm encouraged by the increasing wave number 1 EP flux from model forecasts by Berlin strat forecasts by day 10, also wave number 2 EP flux evident via Euro ridging ... which should continue to put pressure on the vortex.

I guess with the strong El Niño with typical Dec climb it brings and the more amplified MJO signal now forecast, the pattern for the rest of this month may remain unfavourable for blocking. But the consistent wave flux signals from the models suggest energy transfer to the strat will continue unabated and will hopefully lead to a weakening in the New a Year ... fingers crossed not much of a wait!

Thanks Nick, couldn't have hoped for a better response than this. Strat mechanisms are not my forte.

[Costa Del Fal]

16 minutes ago, Nick F said:

 

Current ECMWF and GFS runs both indicating impressive  strat warming over eastern Siberia from about day 5 onwards, which could help dudge the strong PV at least in the meantime. Also I'm encouraged by the increasing wave number 1 EP flux by Berlin strat forecasts by day 10, also wave number 2 EP flux evident via Euro ridging ... which should continue to put pressure on the vortex.

 

Hi Nick, I am looking to improve my knowledge and understanding of the stratosphere and the forecasting tools available for this. Could you pass on the sources you use, especially in terms of wave forecasts as you mention above? 

Cheers.

[Nick F]

13 minutes ago, Costa Del Fal said:

Hi Nick, I am looking to improve my knowledge and understanding of the stratosphere and the forecasting tools available for this. Could you pass on the sources you use, especially in terms of wave forecasts as you mention above? 

Cheers.

The Berlin stratosphere diagnostic tools using ECM data are freely available and have wave flux forecasts but you have to register to access them,  they email to say you have been granted access within a few days if I remember rightly, link here:

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

Andreas Dornbrack's site is very good:

http://www.pa.op.dlr.de/arctic/ecmwf.php

Netweather extra GFS chart viewer has stratospheric temp charts for 10/30/100 hPA. Or there is the NOAA Climate Prediction Centre strat forecasts and analyses here

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/

Tokyo Climate Centre another reasonable source:

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

 

 

 

 

[Costa Del Fal]

Cheers Nick. In short for now, no surprise to see such zonality and low arctic height profiles with the strat at 30hPa well below normal temperature wise for this stage of the season!

Edited December 11, 2015 by Costa Del Fal

[lorenzo]

Going to add to this list too...

 I know when the models come out everyone will have wetterzentrale or meteociel open, both seem to deliver the latest model runs immediately, netwx has the best rendering of the 10 and 30 strat plots around. Then you have instant maps which are worth a look, but compare how sparse the depiction is.

On meteociel, very familiar with everyone for NH H5 look,  looking at wave impacts try it on 1.5 PVU tropopause level provides a great view of things, especially where animated.

Further to that are the NASA vorticity animations similar to dornback site mentioned above.

http://acdb-ext.gsfc.nasa.gov/Data_services/arctic/

Guide to Isentropic heights and  PV Levels as per ECMWF dataset here

Can't stress enough how useful the animated plots are from nasa - especially when watching wave breaks at different levels in the atmosphere, on occasion you see poetry.

Edit - it is remiss of me not to mention Andrew's contribution, once you get used to the bunch of charts linked above and here you will see just how well he takes things to a new level.

 

 

Edited December 11, 2015 by lorenzo

[Nick F]

6 minutes ago, lorenzo said:

On meteociel, very familiar with everyone for NH H5 look,  looking at wave impacts try it on 1.5 PVU tropopause level provides a great view of things, especially where animated.

 

Yes, that animation illustrates well the poleward wave energy produced by the Euro ridge ... 

[sebastiaan1973]

I spoke today to someone of MeteoGroep (group) Netherlands. They expect a warm januar and possibilities in februar for cold weather. In their opinion the  chance for a minor SSW is high.

 

 

[bluearmy]

High up in the strat, gfs  00z op brings the Pacific ridge into the western states which forces the trough axis East. That would tend towards a colder pattern for Europe if replicated lower down. 

[Ruben Amsterdam]

What to say? GFS is forecasting some sort of minor event now within the +240hr range. At the same time, it appears that this will not at all be enough to bring the vortex down. Any thoughts/calculations on how this will affect zonal wind speeds and whether we can expect any tropospheric responses? 

[snowking]

I haven't got time unfortunately for anything too in depth Ruben but should that pattern downwell in tandem with the 10mb pattern one would expect an uptick in the jet energy on this side of the Northern Hemisphere, at least temporarily, whilst the vortex gets displaced towards the Atlantic sector.

Beyond that it's all just down to whether we can get any secondary wave attacks before the PV relocates to its spiritual home over the pole.

 

SK

[bluearmy]

9 hours ago, bluearmy said:

High up in the strat, gfs  00z op brings the Pacific ridge into the western states which forces the trough axis East. That would tend towards a colder pattern for Europe if replicated lower down. 

The 06z and 12z didn't repeat this

note that temp at 1mb gets to plus 10c below T200

those forecasts which were at two weeks look likely to verify but they aren't going to induce anything drastic on the short term

[Nick F]

The CFSv2 10hPa weekly forecasts last few runs out to 10th Jan suggest an elongation and gradual shift of the stratospheric vortex towards Scandinavia looking at the loop below - need to click play:

http://www.tropicaltidbits.com/analysis/models/?model=cfs-avg&region=nhem&pkg=Tz10_7d&runtime=2015121312&fh=666&xpos=0&ypos=277

 

Edited December 13, 2015 by Nick F

[Duane S.]

Very decent wave 2 forecast this morning from the ECM...

 

[Ruben Amsterdam]

Wave-2? Didn't see that one coming... More interesting things this morning: quite a significant difference between EC and GFS at 1 hPa +240hrs. GFS forecasting height increases in the Japanese sector, EC in the European (hence the wave-2 I think). EC does show the "Japanese" high in the levels below (2,3,5 hPa), is it hinting on something starting from the top? I must say the +21C in the EC forecast is quite impressive. 

 

Edited December 14, 2015 by Ruben Amsterdam

[lorenzo]

After a weekend of looking at some pretty uninspiring output - the wave 2 is impressive, as are the temps at 1hPa.

Looking at PV plots at roughly, 10, 30 and 50 hPa the elongation of the vortex is clear at the top of the strat, something of an attempt at a split visible here at D10, but not quite there on the height plots yet.

Aggregate Heat Flux 

Wave 1 continuing it's background work, as noted the wave 2 very progressive on this run, from  the freezer to something a lot more purposeful.

This flux clearly visible on the graph plots, combined with an uptick in u wind at top level, some reduction at 10hPa and EP vectors developing.

Following from an interesting week of debate on twitter, Cohen mentioned an update to his AER blog perhaps today. A step forward also for Wave Activity Flux highlighted in his model here.

At least something to keep an eye on after a weekend of boring output and some winter misery setting in regarding the Xmas period on the models.

The 600K Potential Vorticity chart above for me highlights the work to be done still whether that Wave 2 can get through the heart of the thing remains to be seen, this may be a nudge, it may be a softening blow, it may be the one that tees up the vortex for the next round of MT influence, would love the latter but remain cautious.

[chionomaniac]

2 hours ago, s4lancia said:

Very decent wave 2 forecast this morning from the ECM...

 

At first glance with the ECM Berlin data it appears that the wave 2 is far stronger than the wave 1, but that is not the case at all. The scales surprisingly and confusingly are different so that the wave strengths are the same for both. I put this in the lower end of moderate category. The wave 1 shows through most because it has the wave 2 element on top of the wave 1 reinforcing it.

[Ruben Amsterdam]

8 hours ago, chionomaniac said:

At first glance with the ECM Berlin data it appears that the wave 2 is far stronger than the wave 1, but that is not the case at all. The scales surprisingly and confusingly are different so that the wave strengths are the same for both. I put this in the lower end of moderate category. The wave 1 shows through most because it has the wave 2 element on top of the wave 1 reinforcing it.

I remember reading here one day that wave-2 geopotentials can be more disruptive at lower m' values? Hence maybe the different color scales: 1200 m' is more impressive for wave-2 than it is for wave-1.

Speaking of wave-2, just checked the 2008/09 thread and check out the EPV and heat flux on some of these historical forecasts!

[Cloud 10]

Nice to take a trip down memory lane occasionally,and maybe we will be seeing stuff like this verifying come early-mid January.

 

 

 

Edited December 14, 2015 by Cloud 10

[feb1991blizzard]

19 minutes ago, Cloud 10 said:

Nice to take a trip down memory lane occasionally,and maybe we will be seeing stuff like this verifying come early-mid January.

 

 

 

Or this!!!!!   -   The best you can get, a wave 2 split slicing vertically (on map) through Greenland.

[Grimsby Snow Lover]

Could someone explain what the wave 2 activity posted above would mean for our winter weather. I'm  a complete novice when it comes to the strat. 

Edited December 14, 2015 by Grimsby Snow Lover

[Snowy L]

Latest Cohen

https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

Still expects a significant weakening of the vortex in January.