Stratosphere and Polar Vortex Watch

[chionomaniac]

20 hours ago, knocker said:

Just to clarify a point chio when you say reflective of the southerly displaced jet stream are you talking of the Subtropical jet because 30n is just about where it sits or the Polar jet a long way south?

Diagram courtesy Atmosphere, Weather & Climate by Barry and Chorley

 

yes sorry, i was rushing!

[bluearmy]

Berlin charts again reveal the upper/mid zonal flow easing off re working it’s way down towards the lower strat into week 2.

[Allseasons-Si]

Can anyone on here explain this,and what would it mean for our part of the world(if it came off),thanks.

 

[northwestsnow]

1 hour ago, Allseasons-si said:

Can anyone on here explain this,and what would it mean for our part of the world(if it came off),thanks.

 

Thats good news if it happens .

[Interitus]

 

10 hours ago, Allseasons-si said:

Can anyone on here explain this,and what would it mean for our part of the world(if it came off),thanks.

 

Primarily it is a reflection of the tropospheric vortex switching from the Canadian side of the Arctic to the Siberian.

The real stratospheric action is higher up where GFS forecasts have been hinting at some wave 1 forcing, for example -

 

[northwestsnow]

 

 

GFS @72 hours

 

 

 

 

GFS 00z @384 hours- coldest air over scandy- not sure of the implications if there any for the UK.

Edited November 17, 2017 by northwestsnow

[Paul_1978]

And that would be a good thing @Interitus?

[Blessed Weather]

The latest update from Berlin (17 Nov) shows the Zonal Mean Zonal Wind of the strat vortex at 10hPa 60N is forecast to reduce from 34 m/s today to 28 m/s by Day 10 as the stronger flow that was filtering down to the lower strat retreats back up. But bearing in mind that the record low zonal wind speed for this stage of the season was 5.4 m/s in Nov 2009 I suspect this will not be enough to stop the strat and trop vortex coupling in the short-term? If so, it’s good to see possible wave forcing appearing in the forecasts to hopefully aid disruption.

 

Berlin charts for today, day 5 and day 10 with 10hPa 60N marked with a cross.

[karyo]

45 minutes ago, Blessed Weather said:

The latest update from Berlin (17 Nov) shows the Zonal Mean Zonal Wind of the strat vortex at 10hPa 60N is forecast to reduce from 34 m/s today to 28 m/s by Day 10 as the stronger flow that was filtering down to the lower strat retreats back up. But bearing in mind that the record low zonal wind speed for this stage of the season was 5.4 m/s in Nov 2009 I suspect this will not be enough to stop the strat and trop vortex coupling in the short-term? If so, it’s good to see possible wave forcing appearing in the forecasts to hopefully aid disruption.

 

 

 

Berlin charts for today, day 5 and day 10 with 10hPa 60N marked with a cross.

 

 

 

Thank you for making it so clear! I always find it difficult to read those charts. 

[Northern Sky]

3 hours ago, Paul_1978 said:

And that would be a good thing @Interitus?

Just my take on it and it may well be wrong but the tropospheric vortex moving to the Siberian side of the Arctic allows for the possibility of height rises in it's usual home - ie Greenland, thus giving us a better chance of cold. Of course as we have seen it also raises the chance of a west based -NAO which is not good for us.

At the moment we are seeing a disconnect between the stratospheric and tropospheric vortex but it seems likely that this won't last. The wave 1 activity Ineritus mentions in the stratosphere could result in a displacement of the vortex - it could bump it away from Greenland, which might be a good thing if the tropospheric and stratospheric vortex has become coupled.

Of course there are lots of if's and maybes and perhaps a displacement caused by warming could bump the vortex somewhere unfavourable for us?

Wouldn't be the first time I've got it all wrong but thought I'd have a go and very happy to be corrected by those more knowledgable.

[bluearmy]

I am still troubled that posters feel that the stronger zonal flow will downwell to the lower strat and upper trop area at a latitude which affects our chances for cold negatively. all I see is any strength in the zonal flow being at a latitude south of our location. If you are looking for snowfall then you need some strength in the jet to bring systems up against any blocking. Of course the apparent disconnect between the upper strat and low down may continue anyway.

that wave activity high up was showing a few days ago - good to see its strengthening - hopefully it will verify. 

[sebastiaan1973]

I think everybody noticed the predicted transition of the polar vortex to the east part of Siberia. Which would enhance the North pacific jet.

 

[Singularity]

So if I'm reading the above right, the interaction of the approaching polar vortex with the preceding blocking highs across N. Asia is primarily or entirely responsible for the vertical wave activity flux and subsequent warming in the upper stratosphere? 

Busy with other matters today so leaning on others to do some of the thinking for me - I hope you don't mind  - cheers!

[summer blizzard]

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/wind/u60n_10_2017_merra2.pdf

A simple look at NASA should tell us not to be concerned about the stratosphere at this stage. We are more or less proceeding at an average pace and actually better positioned now than say the winters of 09 or 13 which saw near record zonal winds headed to their peak. Equally zonal winds in the winter of 06 never really got off the mark and we missed the boat in terms of severe weather for the most part. 

As things stand we'd expect the stratosphere and troposphere to couple (though as alluded to, it's not hurrying up - probably average pace though) however the hope should be that with a less aggressive background, we may be able to see a weakening of zonal winds in the mid-December to mid-January period. 

[Blessed Weather]

I wasn't sure where to post this, so forgive me if it's not appropriate here, but here's the latest thoughts from MO man John Hammond, posted today, as he discusses "Battleground Britain" and the influence of stratospheric winds on current weather patterns. Extracts:

We’re set to see some dramatic contrasts in the weather as November draws to a close. Cold and warm air will be vying for supremacy across our shores, generating some ‘interesting’ weather, to say the least.

Scientists are looking for signs at the very top of the atmosphere. The relationship between stratospheric winds and our weather patterns at ground level is still only beginning to be understood. But it’s known that sometimes these two atmospheric zones ‘hook up’ and blow in tandem. Other times, as at present, they seem strangely disconnected.

If strong westerly winds in the stratosphere start to drill down through the atmosphere, our jet stream will become super-charged. What does that mean? In all likelihood, a more clear-cut mild, wet and windy period of westerly winds would result.

However there are currently no clear indications of a ‘hook-up’ between the top and bottom of the atmosphere. My hunch is therefore for a continuation of the current meanderings of warm and cold air, which the computer models will continue to struggle with.

Full article: https://weathertrending.com/2017/11/17/horizon-battleground-britain/

[Catacol]

23 hours ago, Singularity said:

So if I'm reading the above right, the interaction of the approaching polar vortex with the preceding blocking highs across N. Asia is primarily or entirely responsible for the vertical wave activity flux and subsequent warming in the upper stratosphere? 

Busy with other matters today so leaning on others to do some of the thinking for me - I hope you don't mind  - cheers!

That’s my reading of it. Low pressure moving to the west of the Himalayas while high pressure moves further east causing transfer of energy to the atmosphere via mountain torque and consequent vertical wave activity.

[Catacol]

15 hours ago, summer blizzard said:

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/wind/u60n_10_2017_merra2.pdf

A simple look at NASA should tell us not to be concerned about the stratosphere at this stage. We are more or less proceeding at an average pace and actually better positioned now than say the winters of 09 or 13 which saw near record zonal winds headed to their peak. Equally zonal winds in the winter of 06 never really got off the mark and we missed the boat in terms of severe weather for the most part. 

As things stand we'd expect the stratosphere and troposphere to couple (though as alluded to, it's not hurrying up - probably average pace though) however the hope should be that with a less aggressive background, we may be able to see a weakening of zonal winds in the mid-December to mid-January period. 

Yes - and the longer the “hurrying up” is delayed the better it will be when the next cycle of Pacific forcing begins. 

It’s only Nov 18 and it feels like winter has been underway for eons - so much discussion and focus! It really is early days and sooooo much patience is required.

[ArHu3]

16 hours ago, summer blizzard said:

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/wind/u60n_10_2017_merra2.pdf

A simple look at NASA should tell us not to be concerned about the stratosphere at this stage. We are more or less proceeding at an average pace and actually better positioned now than say the winters of 09 or 13 which saw near record zonal winds headed to their peak. Equally zonal winds in the winter of 06 never really got off the mark and we missed the boat in terms of severe weather for the most part. 

As things stand we'd expect the stratosphere and troposphere to couple (though as alluded to, it's not hurrying up - probably average pace though) however the hope should be that with a less aggressive background, we may be able to see a weakening of zonal winds in the mid-December to mid-January period. 

And last year, around this time,  we nearly hit below 2 standard deviations weak polar vortex and that got us very little winter too

[Mattias]

In the short term forecast, looking att zonal mean zonal winds and EP-fluxes, there seems to be some downward wave reflection from the lower strat with EP-flux convergence and deceleration of the zonal winds north of 60N in the troposphere. Maybe that could be contributing to the building of the greenland blocking during the next couple of days?

Thats my interpretation, but since I am no expert it might be wrong. Further out in the forecast the downward reflection in the lower strat disappears and some gfs runs have shown some signals of weakening of the upper strat, but yet not much to feel very excited about. 

[lorenzo]

Some more plots and charts to complement the previous commentary.

Wave driving and flux activity showing as nothing out of the ordinary here.. Berlin view kind of dampens the JMA Eliassen flux view from last week.

At the top of the house we can see the action alluded to at 1Hpa - by 7 it's a robust picture

475K view looks busy at Day 10 and to my eye shows a vortex getting lively..

u wind predicted to get it's act together across the range too even with the slow down of 8 ms-2 in the immediacy across 10hPa.

The aggregate Nasa Newman plot suggests not far off a column connect. Interesting regime ahead. What would be cool is a visualization of the definitive eQBO layers and progression for tilt of the vortex vs. the Vortex Intensification period that is in the post, that may give some tells. Good to see Anthony's take on the pacific nuances also - definitely keep an eye on this insight.

 

[lorenzo]

Sorry double post - another thought... Has anyone caught a good definitive paper on the cause of the QBO disconnect? I know that this was initially loosely ascribed to strength of El Nino, however given the fact it was the first time this regular rhythm had experienced such a disruption, am not entirely convinced this is solely the driver of such an event.

From a weather perspective I have been too busy at work since Nov 2016 to stay close to all the academia - what is of interest though is the ongoing research with CMIP6 and definition of EPF - Energetic Particle Forcing. Attached image from this paper https://www.frontiersin.org/articles/10.3389/fphy.2014.00025/full#B32

 

In July this year EPF was mapped across all it's spectrums for influence on the stratosphere and climate modes, even extending the view into the mesosphere, something Anthony and I had puzzled over last winter wrt changes in Hadley cells and stream function.

Great that in July this is incorporated into the model to take a view on the true solar influence and moves the conversation from Flux / Sunspots to the particle physics driving subtle changes. Early days here and difficult to map to sensible weather / analogs / stratospheric definitive. However good that this is staged for future examination / re-analysis. A real step forward from increasing the lid of modelling to include a completely new dynamic...

 

[bluearmy]

operational ecm has a distorted vortex at 30 hpa by day 10 

the general movement of upper vortex to the Asian side is well agreed with gefs. would be nice to finally get a connect from top to bottom with the jigsaw pieces in the right places !!

day ten ec op output notoriously unreliable ........

[Interitus]

11 hours ago, lorenzo said:

From a weather perspective I have been too busy at work since Nov 2016 to stay close to all the academia - what is of interest though is the ongoing research with CMIP6 and definition of EPF - Energetic Particle Forcing. Attached image from this paper https://www.frontiersin.org/articles/10.3389/fphy.2014.00025/full#B32

 

In July this year EPF was mapped across all it's spectrums for influence on the stratosphere and climate modes, even extending the view into the mesosphere, something Anthony and I had puzzled over last winter wrt changes in Hadley cells and stream function.

Great that in July this is incorporated into the model to take a view on the true solar influence and moves the conversation from Flux / Sunspots to the particle physics driving subtle changes. Early days here and difficult to map to sensible weather / analogs / stratospheric definitive. However good that this is staged for future examination / re-analysis. A real step forward from increasing the lid of modelling to include a completely new dynamic...

 

Interesting stuff, but important to note they exclude SSW years. This was so they could determine season long effects of the different solar forcings, but as they identify differences in vortex strength as early as October and November it maybe could have included whether there was any significance for SSW.

[Dennis]

30Hpa warming (wave) 

[bluearmy]

Dennis highlights a bit of surfing day 9 at 30hpa. Later on higher up there is evidence of that forecasted 'warming' noted a couple days ago at the top of the strat getting down as far as 10hpa over e Asia. Long way off still.