Stratosphere and Polar Vortex Watch

[Kirkcaldy Weather]

 

[JeffC]

38 minutes ago, Kirkcaldy Weather said:

 

as visualised here also..

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[Kirkcaldy Weather]

 

[frederiksen90]

Compare to 2009: https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2009.gif

Here, PV is markedly strengthened in October with downward movement. At the same time, increasing tropospheric blocking prevents a coupling, which then significantly reduces PV. Today we seem to have seen the peak of PV in October? Now, is increasing tropospheric blocking by forcing PV into a displacement / weakening in November? https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2019.png

After all, does it seem clear that the downward negative anomalies will stop and perhaps disappear completely in November and be replaced by positive anomalies? : D I really think the dynamic seasonal models are having problems this year and they don't understand why the troposphere is blocked and what creates a constant -NAO. Solar minimum? It continues in the opposite direction for the first 7-10 days.

[Catacol]

2 hours ago, frederiksen90 said:

Compare to 2009: https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2009.gif

Here, PV is markedly strengthened in October with downward movement. At the same time, increasing tropospheric blocking prevents a coupling, which then significantly reduces PV. Today we seem to have seen the peak of PV in October? Now, is increasing tropospheric blocking by forcing PV into a displacement / weakening in November? https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2019.png

After all, does it seem clear that the downward negative anomalies will stop and perhaps disappear completely in November and be replaced by positive anomalies? : D I really think the dynamic seasonal models are having problems this year and they don't understand why the troposphere is blocked and what creates a constant -NAO. Solar minimum? It continues in the opposite direction for the first 7-10 days.

It certainly makes the November Glosea update interesting to contemplate... though by Nov 14 perhaps we will have coupling imminent or underway. It’s tempting to get ahead of current conditions and I agree that broadly speaking the North Atlantic SLP profile is working out differently than long range forecasts suggested but it is still only Oct 29. Realistically we are 7/8 weeks away still from true winter potential in the south of England, High ground snow lovers - enjoy your smug response to that statement...

[knocker]

Strat/Trop coupling? Moving to a +NAO?

Edited October 29, 2019 by knocker

[Catacol]

34 minutes ago, knocker said:

Strat/Trop coupling? Moving to a +NAO?

Certainly a +NAO phase on the way as forecast. The longevity (or not) of the phase will be the interesting bit, and if heights stay strong to our N and E then it is money in the bank over the longer term for potential vortex instability later. I’m not normally interested much in November - 2010 I remember got interesting quite quickly, and curiously also last year given signals that grew... though in the end the final product was a poor winter for cold. This year? We will see. Wet and wild for a bit won’t fill me with much good cheer but if signs of wave 2 warming begin to appear as a counter to the fairly grim long range model forecasts then perhaps some people on here can get some enjoyment out of the season.

Coupling? Not yet. Hopefully not at all!

[feb1991blizzard]

54 minutes ago, knocker said:

Strat/Trop coupling? Moving to a +NAO?

Still maintaining that Scandi high / deep Iberian troughing signal though.

[Sceptical]

Potential spanner in the works.

Realistic expectations..

 

[Mike Poole]

Interesting view of the uncertainty re the strat in these charts from stratobserve.com 

This is based on the GFS and GEFS 0z run, here T192:

Vortex looks squeezed a bit and along the same sort of axis, and from higher heights (red) showing in the same area on all plots.  T384:

The clarity is gone by this point, ellipses are various shapes and the consistent forcing on the vortex isn't there. Well it's T384 - but if there was anything significant on the horizon strat-wise you would see it at this timescale as things are less uncertain up there!  But this is all interesting stuff to keep our eye on as the winter season approaches...

[Catacol]

1 hour ago, Sceptical said:

Potential spanner in the works.

Realistic expectations..

 

What are the works - and what is the spanner?

[Met4Cast]

There continues to be little sign of the strengthening vortex downwelling into the troposphere at the moment with increasing -ve anomalies appearing lower down

The CFS is going full on strat vortex melt down through mid-late November, I'm not sure I've ever seen it be so certain of a SSW?

The model does have a -VE bias so it's likely being a little too optimistic but I'd rather see forecasts like this appearing over a continued strengthening strat forecast.

[Kirkcaldy Weather]

 

[mb018538]

On 30/10/2019 at 09:53, Met4Cast said:

There continues to be little sign of the strengthening vortex downwelling into the troposphere at the moment with increasing -ve anomalies appearing lower down

The CFS is going full on strat vortex melt down through mid-late November, I'm not sure I've ever seen it be so certain of a SSW?

The model does have a -VE bias so it's likely being a little too optimistic but I'd rather see forecasts like this appearing over a continued strengthening strat forecast.

As Simon Lee mentioned :
 

Very strong bias for weak PV. Best to not get over-hyped with this particular forecast.

[Met4Cast]

45 minutes ago, mb018538 said:

As Simon Lee mentioned :
 

Very strong bias for weak PV. Best to not get over-hyped with this particular forecast.

I literally mentioned this in my post 

[Catacol]

46 minutes ago, mb018538 said:

As Simon Lee mentioned :
 

Very strong bias for weak PV. Best to not get over-hyped with this particular forecast.

Even given bias, what is interesting to me is that, once again today, all members of this GFS/CFS suite are pointing to a below average vortex strength by second half of December. The hope is that this is the product of wave 2 forcing, and perhaps setting the vortex up for a major hit in the New Year. Usual caveats....long way off.....snapshot analysis....but catching the eye nonetheless.

Edited October 31, 2019 by Catacol

[ArHu3]

For the past 4 years we have seen record weak polar vortices for November and first half of December only to suddenly pick up strength and start raging until February. I'd rather see a strong vortex early on because what goes up must go down and from the bottom the only way is up. 

[knocker]

 

[bluearmy]

‘Berlin’ data commences tomorrow I think ...

[Duane S.]

Pinch of salt as always, but high up warmings still being toyed with by the GFS.

Even if what is showing were to come to fruition in 16 about days time, it is not particularly potent and not showing as filtering down beyond the very highest levels, so not a lot of cop right now at face value.

But from small acorns maybe...?

[Interitus]

3 hours ago, ArHu3 said:

For the past 4 years we have seen record weak polar vortices for November and first half of December only to suddenly pick up strength and start raging until February. 

Except last year when the vortex was average until SSW at start of New Year. And 2015 when the vortex was strong throughout Autumn and early winter. But, yeah.

[Catacol]

14 minutes ago, Interitus said:

Except last year when the vortex was average until SSW at start of New Year. And 2015 when the vortex was strong throughout Autumn and early winter. But, yeah.

Any thoughts this year Interitus? You have been mostly quiet. Too early to make any general observations?

Edited October 31, 2019 by Catacol

[Kirkcaldy Weather]

 

[Kirkcaldy Weather]

First few of the ensembles to show the yellow colours appearing, also others still showing possible elongating and stretching of the PV. As I said in my post in the mod thread a few days ago every little helps, lets see if it develops into anything substantial..

  

[SMU]

If thats day 16 with the usual errors late November ( maybe early December ) looks like some sort of landing zone-

With that in mind it further increases the probability of a below ave December... 

Would be good - Oct / Nov - & poss Dec below ave !!