Stratosphere and Polar Vortex Watch

[Dennis]

Im very interested how the pv will act this winterseason

[Dennis]

 

[sebastiaan1973]

 

[lorenzo]

Good tweet above from Anthony. The papers linked include the Matthewman one which is essential reading imo, also exciting to think ahead for final third of December with another impactful event in the post so to speak.

Such a good watch just now and I think the killer question is around just how much resilience the vortex has this winter.

To my eye it absorbed the W2 from the Scandinavian block readily, however the compounded impact of the current wave 1 looks notable. Plus, this should be followed by well mapped impacts as noted via AAM and MJO cycles and further torque events. With hints of further W2 visible across many layers. Will it absorb these or has there been enough preconditioning of the vortex to allow what lies ahead to deal a killer blow for end Dec.

From looking through previous animations to my eye the most dramatic changes feature some form of block in the Scandinavian/Greenland locale, almost the last piece of the puzzle' that finally creates capitulation.

All this versus the canonical vortex intensification phase makes this season intriguing..

Also, if not end of December period will this mean its game over in the hunt for technical SSW this season....

[knocker]

 

Edited December 1, 2018 by knocker

[lorenzo]

Couple of charts to support the above chain of events leading to the will it / won't it conundrum....also some detail on heat flux and what this tells us about the December evolution ahead..

Wave 2 forecasts starting to look progressive now - getting very interesting the GEOS Nasa plot really cranks things up.. right up to the 90% mark in fact. W1 peak also shown on the 10hPa MERRA plot.

Heat flux over a longer view and a plot from twitter looking at different categories of vortex evolution based on probabilities derived from Heat Flux activity - look how close the December event ranks vs the Major SSW event - really couldn't be closer.. Link to tweet below.

Berlin Plots ( for old times sake..)

W1 peaks at approx Day 6 and the W2 that follows..

And finally a look at the vorticity plots - plenty of lively action ahead and some neat dynamics on show..

With the probability plot as per above mapped from canonical behaviour / regimes it genuinely is too close to call.. Will the W2 appreciate over time as it approaches verification again... will the much vaunted blocking regime establish, and hold,  to create some real trouble for the vortex.. going to be a good watch!

 

 

 

Edited December 1, 2018 by lorenzo

[Katrine Basso]

At 237 hours

 

[iceman1991]

So guys is there a ssw on the way mid December or end ??

[northwestsnow]

13 minutes ago, iceman1991 said:

So guys is there a ssw on the way mid December or end ??

An intriguing question for sure..

What is abundantly clear is the PV is under attack!

[bluearmy]

34 minutes ago, iceman1991 said:

So guys is there a ssw on the way mid December or end ??

Or not at all ..............

Seems more than feasible that an ssw isn’t required this winter to bring nw Europe some deep cold 

 

[Wilxy]

42 minutes ago, iceman1991 said:

So guys is there a ssw on the way mid December or end ??

There is a warming currently forecast on the Canadian side but what interests me is the possibility of another warming soon after on the Eurasian side as shown on the GFS OP and Parallel. Of coarse its far out so still possible it may not happen or the warming won't be as strong as currently shown but either way its a interesting time. 

[ArHu3]

25 minutes ago, bluearmy said:

Or not at all ..............

Seems more than feasible that an ssw isn’t required this winter to bring nw Europe some deep cold 

 

I'm not so convinced anymore a ssw is a precursor to cold, looking at the dates of known ssws, they mostly seem to occur after cold periods and after many ssws we didn't get a new cold event here in Western Europe 

 

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.earth-syst-sci-data.net/9/63/2017/essd-9-63-2017.pdf&ved=2ahUKEwjnqa2-ioHfAhWH66QKHU6ADfIQFjAAegQIBhAB&usg=AOvVaw2c8j-xVmsFCgg4w3OeL3qf

[ArHu3]

Just stumbled on this tweet, it seems my above feelings were right, a displacement leads to warmth in Europe, we need a split or no ssw at all

 

 

 

Edited December 2, 2018 by ArHu3

[bluearmy]

‘It’s not always that simple’ .........

btw, gefs getting v toasty nw late on ...... vortex v displaced to Siberia and ridge over Canada 

[Rayth]

12 minutes ago, bluearmy said:

‘It’s not always that simple’ .........

btw, gefs getting v toasty nw late on ...... vortex v displaced to Siberia and ridge over Canada 

If it was to move and heights were to rise in its place , would that cause more warming / distress in the strat ?

[bluearmy]

6 minutes ago, Raythan said:

If it was to move and heights were to rise in its place , would that cause more warming / distress in the strat ?

Any amplification in th trop will lead to more stress on the strat ........

[Spah1]

 

[jethro]

May I ask a numpty question …..been reading the Solar thread and it seems the unusually quiet Sun is having quite an impact on the thermosphere, producing cooling. What (if any) impact will this have on the stratosphere?

[Dennis]

Nice strato signs ahead to bring more winter signs in dec

Edited December 3, 2018 by Dennis

[Methuselah]

1 hour ago, jethro said:

May I ask a numpty question …..been reading the Solar thread and it seems the unusually quiet Sun is having quite an impact on the thermosphere, producing cooling. What (if any) impact will this have on the stratosphere?

Thank you, Jethro. That's a question I would have asked, myself, had I not been afraid of feeling a right twit!

[Glacier Point]

FWIW, UK Met model showing a full on warming event for end of the year, as is CFS (which has continued to do so for the last few weeks).

That's not wholly surprising given long lead thoughts of stratospheric behaviour and this plot which, if verified, would be signalling a stratospheric warming within 9 days:

[ArHu3]

20 minutes ago, Glacier Point said:

FWIW, UK Met model showing a full on warming event for end of the year, as is CFS (which has continued to do so for the last few weeks).

That's not wholly surprising given long lead thoughts of stratospheric behaviour and this plot which, if verified, would be signalling a stratospheric warming within 9 days:

This is a displacement right? From what I understood is that these displacements are generally very unfavorable for cold in western Europe

[Snowman.]

18 minutes ago, ArHu3 said:

This is a displacement right? From what I understood is that these displacements are generally very unfavorable for cold in western Europe

Depends where the displacement is, with the above chart you can see the vortex push right over to Siberia due to the Wave being more of Canadian warming which if memory serves me correctly lead Dec 2010.

This is beginning to show in the GFS, retrogression of our Scandi block to somewhere more Greenland bound as the PV looks likely to set-up shop NE leading to a potential of a more northern cold blast. There's a lot of water to flow under the bridge first but the GFS is playing with it so clearly some kind of signal is at play.

But I agree that a split is much better for us rather than just a displacement.

Edited December 3, 2018 by Snowman.

[Snowman.]

Continuing on the Wave 1 shown at T0 is your standard Wave 1 which pushes the PV closer to our north.

https://www.instantweathermaps.com/GFS/2018120306/NH_HGT_10mb_000.gif

Similar to that of December 2015 which wasn't very pleasant in terms of weather for us here. PV while under some stress was just displaced into our vicinity which caused some horribly stormy weather.

Edited December 3, 2018 by Snowman.

[Glacier Point]

Displacement forecast for mid December, but expectation would be for full on warming event to occur towards the end of the month. MJO wave passage through the Indian Ocean will likely delivery the knock out punch.