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Posted
  • Location: st albans
  • Location: st albans
    On 30/01/2021 at 12:50, wellington boot said:

    Can you tell me why the red lines change between the charts? I understood these marked long term average, low and high, but they appear to change.

    Is it the red lines changing or the scale moving  ??

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    It has been interesting to see ECM strat disruption undermodelled this season so far. The wave 1 warming we have been going through was upgraded at short range, and again we have an upgrade in wave 2

    This might be a good time to remind everyone that the Stratosphere charts on Meteociel will not show you whether there is a split in the polar vortex or not - the polar vortex is not just a chunk of c

    As always, a great animation of the SPV from Andrej.  

    Posted Images

    Posted
  • Location: Nr. Tunbridge Wells (150m/450ft asl)
  • Location: Nr. Tunbridge Wells (150m/450ft asl)
    3 hours ago, bluearmy said:

    Is it the red lines changing or the scale moving  ??

    I considered that - definitely changing. Look at one of the posts where charts over several days are posted together. There are very obvious features in the long term average line (if that is what it is...) as well as the min and max lines, that simply disappear or change noticeably from one chart to the next, at the same date.

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    Posted
  • Location: North West of Ireland
  • Location: North West of Ireland
    4 hours ago, bluearmy said:

    The SPV remains with a split forecast (vortices e of greeny  and far ne Siberia)

    not the best for us and perhaps where the prediction of a strong Atlantic is based in the extended ??

     In previous UK Met updates unsettled weather for later February was suggested, so this maybe is what mogrep was seeing. The EC46 will likely change in week 3 now. In any case try to enjoy the cold spell if it comes, rather than focusing on its demise.

    Edited by Bricriu
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    Posted
  • Location: Netherlands
  • Location: Netherlands
    9 hours ago, bluearmy said:

    The SPV remains with a split forecast (vortices e of greeny  and far ne Siberia)

    not the best for us and perhaps where the prediction of a strong Atlantic is based in the extended ??

    I guess it does.

    gensnh-31-1-300.png

    EtJWCcvXcAcyUCY.jpg

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    Posted
  • Location: Isle of Wight
  • Weather Preferences: Snow, Thunderstorms, frost.
  • Location: Isle of Wight

    Hopefully it will be a while in reality before any mobile westerly works its way down to the trop.

     

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    Just now, Griff said:

    I guess it's all academic now? 

    Latest ecm zonal, with reversal 👍

    20210201200922-39e70515ae9a9cc7f3a764cb9b0baa31d31661b6.png

    Zonals here ta

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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    1 hour ago, Griff said:

    Zonals here ta

    Looks like a fast recovery there but the influence of the SSW could continue for now?

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    2 minutes ago, Don said:

    Looks like a fast recovery there but the influence of the SSW could continue for now?

    Uncertainty regarding strat and trop coupling, and also length of delay etc. 

    I would imagine it wouldn't be instantaneous? 🤷‍♂️ 

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    Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
    7 hours ago, Don said:

    Looks like a fast recovery there but the influence of the SSW could continue for now?

    A return to westerlies in the strat could well flush the easterlies down to the trop more, but it will take time, the effects of the SSW will probably still be felt in the trop into March, in my opinion.  However, what that means for the UK is far from clear.

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    Posted
  • Location: Poole, BH14
  • Location: Poole, BH14

    People would do well to watch Mark's latest video and the reason why models are having a hard time right now. Specifically GFS. #maybe 😬

     

    Not sure why this got moved here during new model thread given its model related.

    Edited by Rapodo
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    Posted
  • Location: Hoyland,barnsley,south yorkshire(100m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(100m asl)

    I am surprised no one posted the JMA strat graphs,..another warming on the way?

    pole10_nh.thumb.gif.b40666783a01c44987e637a381c94334.gifpole30_nh.thumb.gif.320d43b9b860c77848db6208099d5cee.gif

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    Posted
  • Location: Dublin
  • Location: Dublin
    On 03/02/2021 at 00:02, Allseasons-si said:

    I am surprised no one posted the JMA strat graphs,..another warming on the way?

    pole10_nh.thumb.gif.b40666783a01c44987e637a381c94334.gifpole30_nh.thumb.gif.320d43b9b860c77848db6208099d5cee.gif

    I did see @Petagna (Marco Petagna, Uk Met office) comment on this yesterday:

    "The latest round of warming in stratosphere above N Pole appears to be coming to end at 10hpa.

    Notable extension of warmth observed down to the 30hpa #pressure level this time.

    The E'ly #SPV stratospheric polar vortex looks set to revert W today..strong vortex recovery in sight"

    Joe

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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    50 minutes ago, jcw said:

    I did see @Petagna (Marco Petagna, Uk Met office) comment on this yesterday:

    "The latest round of warming in stratosphere above N Pole appears to be coming to end at 10hpa.

    Notable extension of warmth observed down to the 30hpa #pressure level this time.

    The E'ly #SPV stratospheric polar vortex looks set to revert W today..strong vortex recovery in sight"

    Joe

    I wonder how long surface conditions will continue to be affected, March perhaps? 

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    Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
    On 04/02/2021 at 15:24, Don said:

    I wonder how long surface conditions will continue to be affected, March perhaps? 

    I reckon about two full months from the original SSW, @Don so might play out until to early to mid march? 

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire

    A case of the proverbial... 

    See you next Tuesday... To the return of the strong SPV... 

    20210208201443-cbe2d3882f3fd54f452bb582825e985bf69932de.png

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    Posted
  • Location: st albans
  • Location: st albans
    25 minutes ago, Griff said:

    A case of the proverbial... 

    See you next Tuesday... To the return of the strong SPV... 

    20210208201443-cbe2d3882f3fd54f452bb582825e985bf69932de.png

    Interesting to see another dip next week any the recovery to some strength for early March perhaps leads us to an early start to spring with the Azores ridging northeast by late March if that stronger upper vortex descends 

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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    1 hour ago, bluearmy said:

    Interesting to see another dip next week any the recovery to some strength for early March perhaps leads us to an early start to spring with the Azores ridging northeast by late March if that stronger upper vortex descends 

    Perhaps still enough for a cold first half to March would you think as Mike stated in his post above?

    Edited by Don
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    Posted
  • Location: st albans
  • Location: st albans
    Just now, Don said:

    Perhaps still enough for a cold first half to March would you think?

    I expect a couple, more downwelling waves before winter is done with 

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    On 08/02/2021 at 20:16, Griff said:

    A case of the proverbial... 

    See you next Tuesday... To the return of the strong SPV... 

    20210208201443-cbe2d3882f3fd54f452bb582825e985bf69932de.png

    ECM zonal latest... 

    20210211201913-ad7e6122979fff28f473e1323a2e5d24d228e36b.png

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    • 2 months later...
    Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

    Looks like the vortex is finally on its way out for this season. ECM has the reversal to summer conditions taking place on average around the 4th May

    Untitled.thumb.png.dc688a6a211d2d2b688592bc77eb3014.png

    GEFS look like they are getting there but not quite in range yet to definitely get an idea

    image.thumb.png.12a6ace740c9ca5555aaa7798f6973ac.png

    CFS look to be similar to ECM in early May for the reversal to summer conditions

    image.thumb.png.b1d43391cf7c9b8037bb6fee31386d8f.png

    Overall a much weaker 2020/21 polar vortex compared with the "Polar Vortex of Doom" from the year before and at one point we looked to be doing the opposite to the previous winter at the same point but February really spoilt that when we went stronger than average although no where near as strong as February 2020

    QBO

    I haven't featured the QBO on here for some time so I thought I would have a look and summarize what is going on with the QBO

    image.thumb.png.742cff34248d27eb10ca027552ff16c6.png

    Based on this chart the EQBO has made some progress since the last time I featured the QBO before the winter started and it looks as though at 30hpa we have almost got rid of the WQBO now. I would expect we will soon be in the EQBO at 30hpa based on this chart

    Untitled.thumb.png.c06ad5615de391c028ebc242500c58c1.png

    Although progress is relatively slow it would seem the EQBO is on its way this time around and with no anomalous easterly forming at around 40hpa this time in the middle of the WQBO it would seem we have had no disruption event this time around so baring no other unforeseen hiccup we should be in the EQBO before the summer at 30hpa in reality

    Untitled.thumb.png.f85e2559c30f707092a64ea9e853f5ad.png

    This chart shows in a different way the progress of the QBO and how we are in the top left region which is the east descending phase part of the plot. At one stage during February it looked like there was going to be a potential failure when seeing that line heading back towards the WQBO section but in March we reversed that trend and started heading down and left again as expected so possible EQBO failure hiccup gone for now

    image.thumb.png.7190f58fa559bd40c3c439e78923389a.png

    This was the state of zonal winds yesterday between the surface and 1hpa. Generally dominated by westerlies except really the EQBO region near the equator between 4hpa and 30hpa and the weakening WQBO between 30hpa and 100hpa.

    image.thumb.png.b51ad00409bfb5341b14158dffa90fb0.png

    In 10 days time you can see a further weakening of the WQBO below 30hpa and the EQBO getting just that bit closer to 30hpa too. A clear descent of the EQBO overall can also be seen too. The other major changes you may have noticed is the strengthening of westerlies in the southern hemisphere and a continuation of the decay of the polar vortex in the northern hemisphere and at 1hpa it looks like the summer reversal is imminent.

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    • 2 weeks later...
    • 4 weeks later...
    Posted
  • Location: Poole, Dorset 42m ASL
  • Location: Poole, Dorset 42m ASL
    On 25/04/2021 at 09:52, sebastiaan1973 said:

     

    An interesting read, thanks for sharing..

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    • 3 weeks later...
    Posted
  • Location: Efford, Plymouth
  • Weather Preferences: Misty Autumn Mornings, Thunderstorms and snow
  • Location: Efford, Plymouth

    Morning all.

    Do we know what the QBO figure was for May or has it not been released yet? Just hoping it's gone down towards a negative number.

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    • 2 weeks later...
    Posted
  • Location: Scunthorpe
  • Location: Scunthorpe
    On 02/06/2021 at 10:22, philglossop said:

    Morning all.

    Do we know what the QBO figure was for May or has it not been released yet? Just hoping it's gone down towards a negative number.

    +0.31 so still just a very weak WQBO but I imagine June should come out negative based on this

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    Posted
  • Location: Netherlands
  • Location: Netherlands

    The influence of the quasi-biennial oscillation on the Madden–Julian oscillation | Nature Reviews Earth & Environment

    https://www.nature.com/articles/s43017-021-00173-9

    Abstract

    The stratospheric quasi-biennial oscillation (QBO) and the tropospheric Madden–Julian oscillation (MJO) are strongly linked in boreal winter. In this Review, we synthesize observational and modelling evidence for this QBOMJO connection and discuss its effects on MJO teleconnections and subseasonal-to-seasonal predictions. After 1980, observations indicate that, during winters when lower-stratospheric QBO winds are easterly, the MJO is ~40% stronger and persists roughly 10 days longer compared with when QBO winds are westerly. Global subseasonal forecast models, in turn, show a 1-week improvement (or 25% enhancement) in MJO prediction skill in QBO easterly versus QBO westerly phases. Despite the robustness of the observed QBOMJO link and its global impacts via atmospheric teleconnections, the mechanisms that drive the connection are uncertain. Theories largely centre on QBO-related temperature stratification effects and subsequent impacts on deep convection, although other hypotheses propose that cloud radiative effects or QBO impacts on wave propagation might be important. Most numerical models, however, are unable to reproduce the observed QBOMJO relationship, suggesting biases, deficiencies or omission of key physical processes in the models. While future work must strive to better understand all aspects of the QBOMJO link, focus is needed on establishing a working mechanism and capturing the connection in models.

     

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