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Stratosphere and Polar Vortex Watch


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Posted
  • Location: New Ash green 150M / 500 FT
  • Location: New Ash green 150M / 500 FT
    4 hours ago, Kirkcaldy Weather said:

     

    If you look at the NAM index tweeted & compare it with the tweet from simon lee you can see that the GFS was a massive outlier against the GEFS mean - so that means the above chart will only represent the operational viewpoint.

    There is no chart constructed for the NAM for the GEFS mean -

    There are the elliptical diagnostics that will show each member - which would probably be a better indicator....

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    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

    Following on from the Simon Lee tweet, here is the GFS vs GEFS 12z ZMZW. Spot the GFS -

    gfsvsgefs19112112.thumb.png.533019f5f4c81b0641e6b5bcd31c6195.png

    And the 18z -

    gfsvsgefs19112118.thumb.png.055a9314f43b09c0b9125144014d3a01.png

    GFS not quite as strong towards the end but the ensembles shifting en masse towards the op.

    Notable that under the suggested SPARC/SNAP criteria for assessing NWP skill, the GFS forecast wouldn't even register as a weak vortex -

    snap.thumb.png.507b25855e467eadc6711ff5bc40e744.png

    courtesy A. Charlton-Perez

     

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    Posted
  • Location: st albans
  • Location: st albans

    Following on from @interitus above, the 00z gefs have min mean flow around 15m/s 

    certainly weaker than average but certainly not the drop most were anticipating ..... my thoughts revert back to Andrej’s comments a few days ago that the actual charts are more informative than the mean graphical representation???

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    Posted
  • Location: Camborne
  • Location: Camborne

    A quick glance at the 100, 50 and 30mb gph charts with the gfs at t192 suggests to my untutored eye, significant warming at 30mb, a tight vortex at 50mb and a reflection of the trop 500mb level at 100mb

    2019112100_f192_30.nonenonehghtnonenone_nhem.gfs003.thumb.gif.15fd858440bad17f5478bad0c1963bfb.gif2019112100_f192_50.nonenonehghtnonenone_nhem.gfs003.thumb.gif.d015f77cfbc336af31b65fb6e941e118.gif2019112100_f192_100.nonenonehghtnonenone_nhem.gfs003.thumb.gif.4e14e6bb542c2503017b5b8bee57e015.gif

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    5 minutes ago, knocker said:

    A quick glance at the 100, 50 and 30mb gph charts with the gfs at t192 suggests to my untutored eye, significant warming at 30mb, a tight vortex at 50mb and a reflection of the trop 500mb level at 100mb

    2019112100_f192_30.nonenonehghtnonenone_nhem.gfs003.thumb.gif.15fd858440bad17f5478bad0c1963bfb.gif2019112100_f192_50.nonenonehghtnonenone_nhem.gfs003.thumb.gif.d015f77cfbc336af31b65fb6e941e118.gif2019112100_f192_100.nonenonehghtnonenone_nhem.gfs003.thumb.gif.4e14e6bb542c2503017b5b8bee57e015.gif

    For ease of viewing they've halved the isopleths for the 30mb chart by doubling the contour interval so a misleading comparison.

    The take-out from those charts may be how closely co-located the vortex centres are - little vortex tilt/baroclinicity and warming at that time.

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    Posted
  • Location: Camborne
  • Location: Camborne
    2 minutes ago, Interitus said:

    For ease of viewing they've halved the isopleths for the 30mb chart by doubling the contour interval so a misleading comparison.

    The take-out from those charts may be how closely co-located the vortex centres are - little vortex tilt/baroclinicity and warming at that time.

    Yes I should have mentioned that.

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    Posted
  • Location: Camborne
  • Location: Camborne
    2 minutes ago, Interitus said:

    And I perhaps should have called them isohypse ?

    Funny you should mention that as my finger was just poised ?

    Edited by knocker
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    Posted
  • Location: The Netherlands
  • Location: The Netherlands

    There appears to be a pretty close relationship between max wave1 in November and NAO in December

    https://publish.twitter.com/?query=https%3A%2F%2Ftwitter.com%2Fantmasiello%2Fstatus%2F1197347865481404417&widget=Tweet

    Knipsel.thumb.PNG.8f3dd5a66a0ef4fd24c64f9962c99d19.PNG

    Maximum wave 1 this November off the chart:

    Knipsel3.thumb.PNG.414c37a80c5df7a298faf4350f77403e.PNG

    Seeing some real continuation of the wave1 pattern in the upper layers of the stratosphere as new Eddy heat flux is generated over Russia.

    Knipsel2.thumb.PNG.984272c1968a9b680c8c61a2dc48c402.PNG

    Also because of the favorable conditions of the troposphere for blocking because of the solar minimum, we may expect a siginificant blocking signal next month over the Atlantic.

    I am wondering if the displacement of the SPV will be enough for an official SSW, later next month. 

     

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    2 hours ago, Paul123 said:

     

    I am wondering if the displacement of the SPV will be enough for an official SSW, later next month. 

     

    Got a feeling it will, it looks vulnerable to further attacks, certainly relative to the usual looking vortex in early December.

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    Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL
    17 minutes ago, Interitus said:

    GFS/GEFS zonal wind difference continues on 06z, though the ensembles have some support from the 00z GEOS

    gfsvsgefs19112106.thumb.png.e7ce0d76bcb8746c36956a1610a374a9.png

    What is the x-axis scale on that chart? I initially assumed hours, but that can't be right. Is each tick 6 hours?

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    Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
    6 hours ago, s4lancia said:

    Yep, a bit of a reversal (or not as the case may be) from a couple of days back.

    Monday

    u_60N_10hpa_gefs.thumb.png.9c1be5c2e76a1cdb10891d4347e05ea1.png

     

    Today

    u_60N_10hpa_gefs.thumb.png.ad22f31c8a419c5492fe1764f5587f46.png

     

    GEFS always overshoots the decrease a lot at the end of a run, it also overshoots the increases at the end of the run but not that much. In previous years in reality the speeds always oscillate up or down 

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    1 hour ago, Yarmy said:

    What is the x-axis scale on that chart? I initially assumed hours, but that can't be right. Is each tick 6 hours?

    Yes, 6-hourly forecast times, just an unformatted rough and ready plot!

    Edited by Interitus
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    Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

    i didnt think decembers of 69, 76, or 83 were particuarly cold...

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    4 minutes ago, mushymanrob said:

    i didnt think decembers of 69, 76, or 83 were particuarly cold...

    They might have been in America though.

    EDIT : who knows anyway, he might be referring to cold ENSO episodes or something else.

    Edited by feb1991blizzard
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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    6 minutes ago, Summer Sun said:

     

    Yes, feet firmly on the floor for a while yet.

    Edited by Don
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