Jump to content
Cold?
Local
Radar
Snow?

Stratosphere and Polar Vortex Watch


Recommended Posts

Spotted a post you think may be an issue? Please help the team by reporting it.
  • Replies 3.9k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

Posted Images

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.

    • Like 1
    Link to post
    Share on other sites
    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.
    • Like 7
    Link to post
    Share on other sites
    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

    • Like 5
    • Thanks 1
    Link to post
    Share on other sites
    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    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 !

    • Like 2
    Link to post
    Share on other sites
    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!

    • Like 6
    Link to post
    Share on other sites
    Posted
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
  • Weather Preferences: clear skies , hard frost , snow !
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
    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...

     

     

    • Like 2
    Link to post
    Share on other sites
    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.
    • Like 6
    Link to post
    Share on other sites
    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.

    Link to post
    Share on other sites
    Posted
  • Location: Clayton-le-Woods, Chorley, Lancs
  • Weather Preferences: Snow
  • Location: Clayton-le-Woods, Chorley, Lancs

     

    • Like 1
    Link to post
    Share on other sites
    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
    • Like 8
    Link to post
    Share on other sites
    Posted
  • Location: New Ash green 150M / 500 FT
  • Location: New Ash green 150M / 500 FT

    ^^^ 00Z GFS ENS had earliest split at 264

    ENS suite for 00z now up to 18/64 for a split @day 16

    BF72B802-3E12-4DBA-A95E-9D77FA25EB1F.thumb.png.269373a9448033d0f1012e54f9a8ed6d.png

    • Like 3
    Link to post
    Share on other sites
    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?

    Link to post
    Share on other sites
    Guest
    This topic is now closed to further replies.
    • UK Storm and Severe Convective Forecast

      UK Severe Convective & Storm Forecast - Issued 2021-05-13 09:41:14 Valid: 13/05/2021 0600 - 14/05/2021 0600 THUNDERSTORM WATCH - WEDS 13TH MAY 2021 Click here for the full forecast

      Nick F
      Nick F
      Latest weather updates from Netweather 1

      Cool & showery theme to continue for the foreseeable as low pressure sticks close by

      Showers or longer spells of rain to end the week and through the weekend. Some sunny spells too, but staying on the cool side, with temperatures generally remaining below average. Staying unsettled next week too. Read the full update here

      Netweather forecasts
      Netweather forecasts
      Latest weather updates from Netweather

      Weekend plans: Day trips and evenings out

      Little change by this weekend with further heavy showers. There will be some warm sunshine in between but temperatures remain in the teens with more of a breeze. Still cool for sitting out. Read more here

      Jo Farrow
      Jo Farrow
      Latest weather updates from Netweather
    • Recently Browsing   0 members

      No registered users viewing this page.

    ×
    ×
    • Create New...