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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Livingston (ish)
  • Location: Livingston (ish)
11 hours ago, SteveB said:

Thanks Snowking, was kind of what I thought reading what was said in this thread and on twitter.

Whole Winter is looking promising, what could possibly go wrong.

You had to say that, didn't you? You just had to say that! If the rest of the winter ends up warmish and wet I'll know who to blame and I'll be hunting you! Within an hour I fully expect a monster of a PV to set up bang on the pole and a return of last year's Azore's slug.

Having said that, yes it does seem promising. I'm surprised how quiet this thread has been. If the trop and strat finally manage to couple, what changes might that bring?

 

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21 minutes ago, Fiona Robertson said:

If the trop and strat finally manage to couple

 

Lol, they are coupled!

Geopotential wave 1 from troposphere is creating a prominent stratospheric Aleutian high pressure, displacing the stratosphere vortex. In return, it appears that there may be wave reflection back to the troposphere linking the the stratospheric high with troposphere ridge on Pacific coast of North America - watch the Hannah Attard animation of 10mb and 500mb geopotential heights here - http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

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Posted
  • Location: Livingston (ish)
  • Location: Livingston (ish)
1 hour ago, Interitus said:

Lol, they are coupled!

Geopotential wave 1 from troposphere is creating a prominent stratospheric Aleutian high pressure, displacing the stratosphere vortex. In return, it appears that there may be wave reflection back to the troposphere linking the the stratospheric high with troposphere ridge on Pacific coast of North America - watch the Hannah Attard animation of 10mb and 500mb geopotential heights here - http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

So they finally got their act together...

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Posted
  • Location: St Albans, 95m asl
  • Location: St Albans, 95m asl
7 hours ago, Interitus said:

 

There has been much research in the 12 years since this was published, advancing many of the ideas which are described therein, but a definitive description of coupling processes still doesn't appear to be complete.

Yeah that's a fair point and I think in all the years this thread has been going we have mostly talked about coupling in the context of stratospheric influence on the troposphere (probably because that's what we've mostly been interested in) - so perhaps we need to start talking in terms of ascending and descending 'coupling'

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On 12/7/2017 at 17:19, snowking said:

Yeah that's a fair point and I think in all the years this thread has been going we have mostly talked about coupling in the context of stratospheric influence on the troposphere (probably because that's what we've mostly been interested in) - so perhaps we need to start talking in terms of ascending and descending 'coupling'

Not just this, the 'descending coupling' is more than the Baldwin & Dunkerton downwelling of zonal wind anomalies. As Shaw & Perlwitz note in The Life Cycle of Northern Hemisphere Downward Wave Coupling between the Stratosphere and Troposphere (2013) -

Quote

Overall, the results suggest that stratosphere–troposphere coupling events should be defined using both wave coupling and zonal-mean indices and the impacts in the troposphere should be considered on weather and climate time scales (weekly to interannual). The implications of the connection between downward wave coupling and the NAO phase suggests that general circulation models that do not include a proper representation of stratosphere troposphere dynamical coupling associated with wave reflection

http://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-12-00251.1

This paper highlights many of the other studies into the trop/strat links via hydrostatic adjustment and potential vorticity anomalies which affect the trop-strat and vice versa over the course of days rather than just weeks or seasonally.

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast

Gfs now hinting at a ssw, around Christmas eve, but still a long way out and last year gfs had a tendency to keep on postponing the ssw, for weeks 

Screenshot_20171209-150034.png

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Posted
  • Location: st albans
  • Location: st albans
40 minutes ago, ArHu3 said:

Gfs now hinting at a ssw, around Christmas eve, but still a long way out and last year gfs had a tendency to keep on postponing the ssw, for weeks 

Screenshot_20171209-150034.png

That's not an SSW .............

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
15 minutes ago, bluearmy said:

That's not an SSW .............

I know we need to see the zonal winds decrease /reverse but I don't have access to that data. 

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx

Consistent W1 forecast keeping things interesting and diluting full blown VI, interesting look on 475K also continues - solutions had toyed with something of a regroup but now back to that core over this side of the hemisphere. u acceleration appears to peak across the next 7 days ahead of limited consensus on what happens thereafter.

The 100hPa plots to my eye create a template for continuing amplification also, MJO effects to be considered also. Fun times this winter !

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
On 12/7/2017 at 10:58, Interitus said:

Lol, they are coupled!

Geopotential wave 1 from troposphere is creating a prominent stratospheric Aleutian high pressure, displacing the stratosphere vortex. In return, it appears that there may be wave reflection back to the troposphere linking the the stratospheric high with troposphere ridge on Pacific coast of North America - watch the Hannah Attard animation of 10mb and 500mb geopotential heights here - http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

I think that I would say that this season has seen an upwelling couple - ie the troposphere is engaging and coupling the lower/ middle strat, rather than a downwell coupling where the upper strat (1hPA) is dominant and this influences all levels below it. 

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx

Still seeing an avenue for the Scandi High developing - eventually..

Couple of plots from Berlin, some u tightening at the top of the strat, looks very condensed up there.

Couple of the W1 - peaking at around 1500m mid run.

And, finally Santa has two GEFS elfs going for a very merry chrisswtmas for strat geeks..

ecmwfpv475f240.thumb.gif.2543582dea9410cc7aac55ce29acb67b.gifecmwf10f240.thumb.gif.f68f5d26bdfc972fafc2e37ea2e72795.gif

ecmwfzm_ha1_f192.thumb.gif.98905e4c38f8a6e0d6efb0f95b14abd0.gif168.thumb.png.a87f9ee93af0c9ceed679ec66875c8f4.png

ecmwfzm_u_f240.thumb.gif.99876ac97cf283a22b70493a6f60cb80.gifu_60N_10hpa_gefs.thumb.png.9635cc40bbae8174ab00a51867b65169.png

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Yes this could be a very interesting period coming up as we approach christmas with strat developments, perhaps some significant warming - and a switch come the New Year, something akin to 2013 perhaps but a week or so earlier - will counter the miserable MOD thread over the week ahead - as I suspect the models will ramp up the atlantic whilst not latching onto changes in the strat.

Height rises to the NE as we enter the last week of December perhaps?

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey
2 hours ago, damianslaw said:

Yes this could be a very interesting period coming up as we approach christmas with strat developments, perhaps some significant warming - and a switch come the New Year, something akin to 2013 perhaps but a week or so earlier - will counter the miserable MOD thread over the week ahead - as I suspect the models will ramp up the atlantic whilst not latching onto changes in the strat.

Height rises to the NE as we enter the last week of December perhaps?

Re last paragragh, I definitely go along with that.  How much influence in our back yard is what I’m currently toying with.

Re warmings, are there smaller scale ones that have quick effects or is it only longer large ones that make a difference

BFTP

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Posted
  • Location: st albans
  • Location: st albans

Not a fan of fi gfs strat data but these 16 day op and ens charts are where I think we could be headed with the Pacific ridge splitting the vortex and upwelling 

IMG_0676.thumb.PNG.42a341aa94a84bc60eaca0350ac84e65.PNG IMG_0677.thumb.PNG.d54dd9f87be7d649caac3d08b0930fc9.PNG

Edited by bluearmy
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Posted
  • Location: Norway
  • Location: Norway
On 10-12-2017 at 11:02, lorenzo said:

Still seeing an avenue for the Scandi High developing - eventually..

Couple of plots from Berlin, some u tightening at the top of the strat, looks very condensed up there.

Couple of the W1 - peaking at around 1500m mid run.

And, finally Santa has two GEFS elfs going for a very merry chrisswtmas for strat geeks..

ecmwfpv475f240.thumb.gif.2543582dea9410cc7aac55ce29acb67b.gifecmwf10f240.thumb.gif.f68f5d26bdfc972fafc2e37ea2e72795.gif

ecmwfzm_ha1_f192.thumb.gif.98905e4c38f8a6e0d6efb0f95b14abd0.gif168.thumb.png.a87f9ee93af0c9ceed679ec66875c8f4.png

ecmwfzm_u_f240.thumb.gif.99876ac97cf283a22b70493a6f60cb80.gifu_60N_10hpa_gefs.thumb.png.9635cc40bbae8174ab00a51867b65169.png

True 

87.gif

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Posted
  • Location: Reigate, Surrey
  • Location: Reigate, Surrey
10 hours ago, bluearmy said:

Not a fan of fi gfs strat data but these 16 day op and ens charts are where I think we could be headed with the Pacific ridge splitting the vortex and upwelling 

IMG_0676.thumb.PNG.42a341aa94a84bc60eaca0350ac84e65.PNG IMG_0677.thumb.PNG.d54dd9f87be7d649caac3d08b0930fc9.PNG

Not quite sure how that'll translate at the surface, but doesn't look great for us I suspect (split vortex but with one segment keeping westerlies going across the Atlantic) - please tell me I'm wrong! :-)

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Posted
  • Location: st albans
  • Location: st albans
2 hours ago, Interitus said:

Or on the other hand, maybe...

5a2f9047245e2_umedel6017121200.thumb.png.02a76e2c2403665c3b414eaba5e14a63.png

 

Is that derived from the 00z gefs ?  That run looks to reduce the wave 1 displacement markedly end week 2 and I would be waiting for more runs as this breaks recent continuity  

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
5 hours ago, Interitus said:

Or on the other hand, maybe...

5a2f9047245e2_umedel6017121200.thumb.png.02a76e2c2403665c3b414eaba5e14a63.png

 

Could do with an interpretation of that Interitus - I see a clear uptick in zonal wind speeds in the upper strat downwelling... but how does it relate to a split signalled at 50hpa from a pacific ridge? Your reply is all a bit cryptic for me.... does the mean zonal wind chart contradict the split entirely?

Edited by Catacol
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Posted
  • Location: st albans
  • Location: st albans
12 minutes ago, Catacol said:

Could do with an interpretation of that Interitus - I see a clear uptick in zonal wind speeds in the upper strat downwelling... but how does it relate to a split signalled at 50hpa from a pacific ridge? Your reply is all a bit cryptic for me.... does the mean zonal wind chart contradict the split entirely?

I assume he is pointing out that the 00z gfs was drifting well away from that split scenario 

fortunately the 06z has come back somewhat from that direction of travel 

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3 hours ago, bluearmy said:

I assume he is pointing out that the 00z gfs was drifting well away from that split scenario 

fortunately the 06z has come back somewhat from that direction of travel 

Indeed, but not the 12z.

At this point the strat forecasts are flip flopping with every trop outlook, seen in the ensembles too with a 50m/s spread in zonal wind, here from the 0z, not reliable one way or the other -

u10serie17121200.thumb.png.bd76cb4e9fb3e58d705a235298983841.png

Edited by Interitus
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Posted
  • Location: st albans
  • Location: st albans

Was about to post the drift back on the 12z but Inertius has done it with a graph too

would love to get sight  of the strat eps to see if they are looking more mobile as the ecm op looks similar to the gefs at day 10 

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Posted
  • Location: st albans
  • Location: st albans

GEFS continues with the trend to take the vortex closer to the pole on a trip back to Canada from Siberia end week 2.

given the strength of the wave 1 on berlin at day 10, its a surprise that the displacement signal wains thereafter

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