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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
8 hours ago, Katrine Basso said:

There was a SSW in January of 2009.

And 2008 back end of winter was cold if I remember rightly first decent snowfall here in the sunny Costa del south coast.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
2 hours ago, Singularity said:

ecmwfzm_ta2_f240.gifecmwfzm_ha2_f240.gif

Trending stronger again after that step-down a few days ago. With so much of it internal to the stratosphere (i.e. top-down) I trust ECM/EPS to handle this far more effectively than GFS/GEFS.

Shifts in tropical forcing projections are starting to add more of a wave-2 contribution from the troposphere - hence some additional activity in the mid-levels now showing too.

 

The vortex gets hammered from one region below and two regions above, then another region from below joins the party.

That's why I'd be shocked not to see a technical SSW out of this... and of a split variety no less.

Yes ECM now showing downwelling of reversal down to 5hPa by 26th S.Comparing todays gefs graph with this ecm data from yesterday they are not far apart with the expected reversal at 10hPa just after Christmas.


ecmwfzm_u_f240.thumb.gif.cf503408cf2be17b83a62f08b83f50b3.gifu_60N_10hpa_gefs.thumb.png.4d3c36f9037c3ecd8b769718ff6e0c9c.png


Day 10(now 9) on the 100hPa chart underlines the Atlantic ridging around Christmas.

310055260_ecmwf100f240(1).thumb.gif.d9d209a56de4c7ae06ca02232867fcbc.gif

Of course the unknown is how quickly the drop off in zonal winds filters down to the lowest layers but we should see some real interest in January if these forecasts are correct.

 

Edited by phil nw.
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Posted
  • Location: st albans
  • Location: st albans
42 minutes ago, Interitus said:

Strongest reversal yet for the GFS op on the 0z at -8.5 m/s.

Parallel still not as interested, minimum +2.3 m/s, fascinating.

Yesterday’s ec op 12z was 3.97m/s at day 10. This mornings run continues to sink and stretch the spv so I expect tomorrows Berlin update will show a technical ssw by day 10

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
Just now, Interitus said:

Obliteration of the strat on the GFS 06z - reversal from 264 hrs (29/12 06z) down to -18.7 m/s at t372

Excellent news thanks Interitus

Lets hope that trend continues now !

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

I studied ‘65 as the ‘ultimate displacement’ event.

Still think we’re headed for a split this time though, and sooner rather than later, as the tropical puzzle piece further improves its shape beyond current modelling. It’s been great watching the models adjust as has been anticipated for what feels like an age!

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Posted
  • Location: Cobham Surrey
  • Weather Preferences: clear skies , hard frost , snow !
  • Location: Cobham Surrey
1 hour ago, Interitus said:

Obliteration of the strat on the GFS 06z - reversal from 264 hrs (29/12 06z) down to -18.7 m/s at t372

your my level head @Interitus this seems positive news...

 

 

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Yes it's all looking on course for a Christmas time hit at the top of the vortex as already posted.What we see on day 1 comparing to forecasted day 10 is dramatic as the heat flux  filters down from the top and those oranges turn to blue indicating the zonal winds are reversing.

ecmwfzm_u_a12.thumb.gif.4e2a968cab97821974ab629116816207.gif1826681320_ecmwfzm_u_f240(1).thumb.gif.be808543ade626aa2f6bfd24758b0e15.gif

I like these graphs as they give a simple overview of the expected slowing and then reversing of the zonal winds  at different levels along with wave amplitude and effect on temperature through the vortex.


fluxes.thumb.gif.0f8f58af7f1320b771eb4ba9bc9c612a.giftemps.thumb.gif.71d271321052e951619276469dced8cf.gif

By day 10 on yesterday's forecast at 10 hPa we can already see the squeeze on the vortex  from the warmings suggesting the first stage of displacement is underway.

ecmwf10f240.thumb.gif.611b669cbcfdbab5ea5ea59856978b79.gif

Looking at the day 15 GFS06z forecast we can see this progressing well

NH_HGT_10mb_000.thumb.gif.30b68affea927147a6d378f64bd24549.gif

All this time zonal winds lower down will be decreasing so the effects on our 500h Pa pattern will become more evident in NPW in the coming days .I would expect further weakening of the jet and signs of mid-latitude ridges extending further north into higher latitudes.

 

 

Edited by phil nw.
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Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire

Quite enjoying watching this early SSW evolve and develop. Should be some interesting festive model watching coming up.

Keep up the good work in this thread guys and girls.

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Posted
  • Location: st albans
  • Location: st albans

Hot off the press ..... ec op 12z is different .... split at 10hpa begins at T210 and this downwells to 30hpa by day 10

E5889639-A5AF-43C8-B29C-EFA4A337FE78.thumb.jpeg.59df684d95a714c2bf24ecb69f001fd9.jpeg        3880B625-E51E-424F-956D-062762E0D9F5.thumb.jpeg.087d953db783c455696421eb58b82d9e.jpeg

Note the placement of that ridging ....... I wonder If that’s where it will settle in the trop a week or so  later .....

Edited by bluearmy
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Posted
  • Location: Longton, Stoke-on-Trent.
  • Location: Longton, Stoke-on-Trent.
12 minutes ago, Glacier Point said:

EPS lending support, split signature day 11

Is a split backed up by the various signals or is it likely to ‘only’ be a displacement in your opinion, GP?

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