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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: st albans
  • Location: st albans
11 hours ago, Bullseye said:

Reversal of zonal winds on the most recent 12z ECM. Was also close or just hitting reversal this morning. One to monitor over coming day or two, as a little of surprise (in good way).

Where are  you seeing this ?  Looks relaxed up there for the time of year but nothing notable .......

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Posted
  • Location: North East
  • Weather Preferences: Thunder , Lightning , Snow , Blizzards
  • Location: North East
50 minutes ago, bluearmy said:

Where are  you seeing this ?  Looks relaxed up there for the time of year but nothing notable .......

Yeah it’s gone on further runs 

 

startzonal12z.gif.7b95617eb59ceeb809f536

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Posted
  • Location: st albans
  • Location: st albans
21 minutes ago, Raythan said:

Yeah it’s gone on further runs 

 

startzonal12z.gif.7b95617eb59ceeb809f536

Not sure where accuweather get their data from but that’s not showing what’s happening - it also doesn’t show 60N which is where the reversal needs to occur (technically speaking) but ignoring that, the reversal wave it shows just doesn’t exist ........ it says mean zonal wind speed and it seems to have the area around 30/40N correct below 100hpa, but above that and further north it’s plain wrong  - add to that this just isn’t feasible anyway ! 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
4 hours ago, ICE COLD said:

Do we get a reversal on this mornings ECM 00z run @Bullseye ? Thanks . 

No - ypu wont just get a reversal pop up in 240 hours without it being signalled on the GFS and the ensemble suites first, there hasn't even been a reversal on the GFS within 384 yest (and the GFS is very aggressive with these warmings), the timeframe that a reversal is likely isn't even within 384 yet.

 

EDIT : while we are on the subject, has anyone got the latest 10mb EPS mean T360 height and temperature charts please.

Edited by feb1991blizzard
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Posted
  • Location: st albans
  • Location: st albans
5 minutes ago, feb1991blizzard said:

No - ypu wont just get a reversal pop up in 240 hours without it being signalled on the GFS and the ensemble suites first, there hasn't even been a reversal on the GFS within 384 yest (and the GFS is very aggressive with these warmings), the timeframe that a reversal is likely isn't even within 384 yet.

 

EDIT : while we are on the subject, has anyone got the latest 10mb EPS mean T360 height and temperature charts please.

I think that’s very restricted !  Ventriice sometimes tweets it .......

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Posted
  • Location: Hertfordshire
  • Weather Preferences: SNOW AND FREEZING TEMPS
  • Location: Hertfordshire
48 minutes ago, feb1991blizzard said:

No - ypu wont just get a reversal pop up in 240 hours without it being signalled on the GFS and the ensemble suites first, there hasn't even been a reversal on the GFS within 384 yest (and the GFS is very aggressive with these warmings), the timeframe that a reversal is likely isn't even within 384 yet.

 

EDIT : while we are on the subject, has anyone got the latest 10mb EPS mean T360 height and temperature charts please.

Cheers feb . Yes was a bit confused when I see that post . I thought why is everyone not buzzing if there’s a reversal showing . If we do get a ssw how long after it will the zonal winds take to reverse ? 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
1 minute ago, ICE COLD said:

Cheers feb . Yes was a bit confused when I see that post . I thought why is everyone not buzzing if there’s a reversal showing . If we do get a ssw how long after it will the zonal winds take to reverse ? 

A reversal of the zonal winds at 10mb is the definition (there are new definitions but that's what we have always gone on in the past), how long will it take to bring the Easterlies down to the trop and surface and affect our part of the world though? Sometimes very soon afterwards, sometimes a week or 2, sometimes never at all, if we get one within about 200 hours and its a favourable displacement, just keep watching the charts and hoping, and the analysis from the experts on here.

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

I still think this graph from the ECM-Berlin site is as good as anything for a quick glance.

fluxes.thumb.gif.e0e314874ecfc57532070bbece6d5672.gif

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

when we see the forecast dip on those top 2 readings towards the dotted zero line then it's time to get interested.Yes it's a day behind by the time we see them but it is a simple quick way to monitor the zonal wind speeds.

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

Am I right in anticipating that the huge wave 1 warming has more exciting potential impacts than usual due to the strong wave 2 preceding its that stretches the vortex and, via structural weakening, makes it more vulnerable to penetration and capitulation - even after some reconsolidation?

This being the important distinguishing factor between minor displacements (usually poor outcome for NW Europe) and major ones with extreme weakening of the remnant vortex making its position less of a factor to be concerned about?

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Posted
  • Location: st albans
  • Location: st albans

Back end of gfs op showing temps at the top of the strat which would likely see an ssw occurring not too long after - wonder if we will see that repeat over the next few runs .....

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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
3 hours ago, Singularity said:

Am I right in anticipating that the huge wave 1 warming has more exciting potential impacts than usual due to the strong wave 2 preceding its that stretches the vortex and, via structural weakening, makes it more vulnerable to penetration and capitulation - even after some reconsolidation?

This being the important distinguishing factor between minor displacements (usually poor outcome for NW Europe) and major ones with extreme weakening of the remnant vortex making its position less of a factor to be concerned about?

Hehe maybe. I suspect there are a lot of variables in that analysis that would need unravelling - Interitus might give that a go - but I love the conceptual simplicity of what you are saying, In theory, and given correct angle of attack relative to the shape of the vortex stretch it certainly feels possible. Next 2 weeks gonna be big watching. Where is @chionomaniac these days? I’d be interested to hear his strat exoertise right now.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
2 minutes ago, Catacol said:

Hehe maybe. I suspect there are a lot of variables in that analysis that would need unravelling - Interitus might give that a go - but I love the conceptual simplicity of what you are saying, In theory, and given correct angle of attack relative to the shape of the vortex stretch it certainly feels possible. Next 2 weeks gonna be big watching. Where is @chionomaniac these days? I’d be interested to hear his strat exoertise right now.

This might seem a dumb question, Catacol (it probably is!) but is your favourable 'vortex stretch[ing]' behind the gradual eastward migration, around the Arctic, of sub-25C uppers?:help:

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL

People seem to be getting concerned about the proposed warming kicking the PV back to the Atlantic sector..

Sounds logical but im pretty sure the SSW in Feb was in a similar kind of area (siberia) to what we are looking at now..

 

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx
3 minutes ago, Optimus Prime said:

A brief one from Mr.Bastardi over on Twitter;

 

Sorry, that tells me nothing.

Just going out to my car, should be interesting .. you get my point.

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Posted
  • Location: The Netherlands
  • Location: The Netherlands

At day 12, the GFS is showing the polar vortex to be displaced towards Eurasia. At the same time, this brings temperatures of around -80 degrees to Western and Northwestern Europe at 10 hPa (about 30 km altitude). From what I have read these conditions are favorable for Polar Stratospheric Clouds, so this may be something to watch for in just under two weeks if the GFS turns out to be accurately forecasting the cold stratospheric temperatures.

psc.thumb.png.e661e158a6f7c594ccd101967e3b55e9.png

The area highlighted shows the cold spot that could be favorable for the formation of Polar Stratospheric Clouds. Source: stratobserve.com

 

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Posted
  • Location: st albans
  • Location: st albans
13 hours ago, lorenzo said:

Sorry, that tells me nothing.

Just going out to my car, should be interesting .. you get my point.

Why is going to your car ‘interesting’ tony ?  I would have thought it was fairly standard ......whereas a 50c warming at 10hpa is of note 

joe B is not a strat expert .... he relies on joe D for that. He simply sees a warmer strat leads to blocking below in the trop 

btw, the 00z gfs looks like it reverses at the very top ????

Edited by bluearmy
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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL

The warming looks great to our NE - but do we not need the warming to hit the Greenland region?

I must admit im even more of a novice wrt the strat but looking at the archive for Febs SSW the Greeny 10 Hpa showed the PV sent packing here as well..

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1 hour ago, bluearmy said:

btw, the 00z gfs looks like it reverses at the very top ????

Yes, the GFS 0.25° really goes for it, u1060 of just 3.3 m/s -

347339133_u-component_of_wind_isobaricinGFS_Global_0p25deg_20181210_0000.thumb.png.4f6161b3caddd752bfc1972c7815d673.png

The FV3 (0.25°) not quite as progressive, some reversal at the top but not at 60°, u1060 of 15.9 m/s (blank areas due to Panoply's handling of missing values at 15 and 40mb)

692664091_ugrdprsingfs_0p25_preparafv3_00z.png18121000.thumb.png.de45f0f5c56a34e31ad6c7dee15574c8.png

Also noticeable on the GFS is a roaring subtropical jet at that time.

 

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