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Stratosphere and Polar Vortex Watch


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Posted
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
  • Weather Preferences: clear skies , hard frost , snow !
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
    20 minutes ago, Mike Poole said:

    I think we're beyond that point...

    I get the divergence from the off, if we get a displacement or a displacement followed by vortex split but are we also saying that the SSW is 100% going to happen ? Has a predicted SSW from this time out always materialised ? Genuinely curious ..

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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

    Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
    13 minutes ago, Badgers01 said:

    I get the divergence from the off, if we get a displacement or a displacement followed by vortex split but are we also saying that the SSW is 100% going to happen ? Has a predicted SSW from this time out always materialised ? Genuinely curious ..

    When all models and and all ensemble members are showing it, (the technical SSW (wind reversal at 10 hpa, 60N) it will happen, yes.  Phantom signals in individual runs may of course occur as it's 16 days out, but we are not in that territory, this event is now in the reliable timeframe, it will happen.

    Edited by Mike Poole
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    Posted
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
  • Weather Preferences: clear skies , hard frost , snow !
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
    8 minutes ago, Mike Poole said:

    When all model..

    cheers for the reply , going to be so interesting watching this play out !

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    Posted
  • Location: st albans
  • Location: st albans

    We are fortunate that someone recently tweeted an image of the glosea run from 3 dec for 6 Jan at 10hpa

    BE58065F-BB96-45BA-8B77-A13E36BCEEE9.thumb.jpeg.a76b8810609d803cb4be8661ce290769.jpeg

     

    Looking at the 06z gfs op picture for the end of the year higher up (which one would expect to down well over a few days)

    67C32192-0844-4BBB-955A-0DDE453355B6.thumb.jpeg.bbd3af00a871b28d807577d8ddc7d56f.jpeg

     

     

    Edited by bluearmy
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    Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
    5 minutes ago, lorenzo said:

    Couple of plots to represent the warming vs. the much posted Meteociel 10hPa view.

    From Zacs site a monster 6 SD warming, and clear torching of the strat on the seasonal evolution plots.

     

    gfs_nh-ehflx_20181214.thumb.png.45d03673cacb28b30d4a030829d43366.png1236156317_vT15Dec.thumb.PNG.1673f705eee0ffbface43c5f2c0342e2.PNG

     

    Couple of retro CPC views of u and also the Heat Flux profile, and finally from copernicus seasonal update the forward H5 anom.

    1994272400_U_10mb_60N_2018-2019(1).thumb.png.4615336ab84af4e949882287b2de4a75.pnglat_pres_gfs_vT_NH_f192.thumb.png.085ca711e66cc689f3b21ce5a2138ece.pngconvert_image-gorax-blue-002-b6a07f0b7be1ee2f1ad515c21ca67e14-RW3xJW.thumb.png.97c1131403ac737fb5178788eb337eb1.png

    Lots to look forward to...

    Really interesting charts, thanks for posting them, and reinforces the view that we are on the cusp of something special here.  

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    Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
    25 minutes ago, lorenzo said:

    Couple of plots to represent the warming vs. the much posted Meteociel 10hPa view.

    From Zacs site a monster 6 SD warming, and clear torching of the strat on the seasonal evolution plots.

     

    gfs_nh-ehflx_20181214.thumb.png.45d03673cacb28b30d4a030829d43366.png1236156317_vT15Dec.thumb.PNG.1673f705eee0ffbface43c5f2c0342e2.PNG

     

    Couple of retro CPC views of u and also the Heat Flux profile, and finally from copernicus seasonal update the forward H5 anom.

    1994272400_U_10mb_60N_2018-2019(1).thumb.png.4615336ab84af4e949882287b2de4a75.pnglat_pres_gfs_vT_NH_f192.thumb.png.085ca711e66cc689f3b21ce5a2138ece.pngconvert_image-gorax-blue-002-b6a07f0b7be1ee2f1ad515c21ca67e14-RW3xJW.thumb.png.97c1131403ac737fb5178788eb337eb1.png

    Lots to look forward to...

    beautiful stuff thank you im really starting to learn so much now its amazing extremely interesting.

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

    The rarity of a +6 SD can't be overstated; IIRC that's an order of magnitude beyond the peak rainfall amounts from major hurricane Harvey last year in terms of how exceptional it is... the mind boggles! ?

    The polar vortex should experience more than a little boggling as a result ?.

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    1 hour ago, Singularity said:

    The rarity of a +6 SD can't be overstated; IIRC that's an order of magnitude beyond the peak rainfall amounts from major hurricane Harvey last year in terms of how exceptional it is... the mind boggles! ?

    The polar vortex should experience more than a little boggling as a result ?.

    Great degree of caution required when using the S.D. as the data is far from normally distributed. Not entirely sure on the CFS data used in the chart, but using the MERRA2 year round average and standard deviation the GEOS forecast for the 10 mb heat flux of 355.69 on Dec 23rd is indeed a shade under +6 S.D. In a normal distribution this would be 1 in 506797346 days chance i.e. over 1.38 million years! But the frequency histogram looks like this -

    1464055958_Heatfluxfrequency.thumb.png.0ac6272ca8411b0afd138aa27f81a6b7.png

    Skewed because of practically zero heat flux in summer. Using the December values brings the SD down to 3.93 and for December 23rd excl. 2018 SD 3.68, incl. 2018 SD 3.13. This latter value would still be over 1 in 370 years but there were higher values on 28-30th December 1984 and overall it is 21st highest with most falling in January. The maximum of 564.32 from 19/01/09 is over 58% greater and using the annual mean and deviation would be 9.79 SD which for a normal distribution the chance would be greater than the age of the earth.

     

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    Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
    9 minutes ago, Interitus said:

    Great degree of caution required when using the S.D. as the data is far from normally distributed. Not entirely sure on the CFS data used in the chart, but using the MERRA2 year round average and standard deviation the GEOS forecast for the 10 mb heat flux of 355.69 on Dec 23rd is indeed a shade under +6 S.D. In a normal distribution this would be 1 in 506797346 days chance i.e. over 1.38 million years! But the frequency histogram looks like this -

    1464055958_Heatfluxfrequency.thumb.png.0ac6272ca8411b0afd138aa27f81a6b7.png

    Skewed because of practically zero heat flux in summer. Using the December values brings the SD down to 3.93 and for December 23rd excl. 2018 SD 3.68, incl. 2018 SD 3.13. This latter value would still be over 1 in 370 years but there were higher values on 28-30th December 1984 and overall it is 21st highest with most falling in January. The maximum of 564.32 from 19/01/09 is over 58% greater and using the annual mean and deviation would be 9.79 SD which for a normal distribution the chance would be greater than the age of the earth.

     

    Well that's me thoroughly schooled thanks ?.

    Technically then it shouldn't be the standard deviation being used at all - unless I suppose it had been relative to the specific month as I had assumed (yes, I know, never assume anything...).

    So it's right up there for December events but not January ones. Interesting - I never imagined there to be so much of a difference!

    Edited by Singularity
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    Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
    1 hour ago, Interitus said:

    The SD is fine for comparison as long as it's realised the extremes aren't always as great as they at first appear.

    The dates with stronger 10 mb heat flux represent 9 different periods from 8 winters (with minimum u1060 in following 3 weeks) -

    29/12/84 -16.38
    08/01/91 7.97
    10/01/92 8.95
    22/01/08 19.42
    19/01/09 -31.08
    04/01/13 -12.29
    07/02/16 11.53
    05/03/16 -31.43
    11/02/18 -24.24

    5 of 9 had SSW in following 3 weeks (technically 4 of 9 as March 2016 treated as very early FW)

    Interestingly since and including the first reversal on the GFS 10/12 18z of the 20 runs 7 have had SSW but 13 without. Here are the minimum zonal winds for the runs since 09/12 0z -

    1636304182_gfszonalmin.thumb.png.1a13cfc6f7effd918790cb7f86c9599f.png

    And here are those runs in series (coloured by day) -

    1797508650_gfszonalseries.thumb.png.374841e93584028b80d6904ede373d3a.png

     

    I do get the feeling from your posts that you are a little reticent about this possible ssw event? Please correct me if I'm wrong.

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    Posted
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester
  • Weather Preferences: clear skies , hard frost , snow !
  • Location: London City ,Cobham Surrey , Hale Gtr Manchester

    Ian F on twitter whose posts' I used to enjoy reading on here until he stopped, is now saying early Jan for the warming. Maybe it is being pushed back slightly, delayed but not cancelled ?

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    Posted
  • Location: st albans
  • Location: st albans

    Yesterday’s ec op showed zonal winds at the top of the strat towards the pole upticking and then reversing quite markedly approaching day 10. The uptick appears to be flushing down through the layers ...... probably too crude to assume this could be used as a template for any likely reversal at 60N a few days later. Though If it is the case, expect an increased burst of zonal flow prior to any fun and games 

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    Posted
  • Location: Netherlands
  • Location: Netherlands
    1 hour ago, bluearmy said:

    Yesterday’s ec op showed zonal winds at the top of the strat towards the pole upticking and then reversing quite markedly approaching day 10. The uptick appears to be flushing down through the layers ...... probably too crude to assume this could be used as a template for any likely reversal at 60N a few days later. Though If it is the case, expect an increased burst of zonal flow prior to any fun and games 

    Yes, but where will be the increased burst of zonal flow ?

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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    19 minutes ago, sebastiaan1973 said:

    Yes, but where will be the increased burst of zonal flow ?

    Atlantic sector most likely?

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    Posted
  • Location: st albans
  • Location: st albans
    29 minutes ago, northwestsnow said:

    Atlantic sector most likely?

    That usually happens but if the trop vortex to our ne is less intense then any mid lay block could use that mobility to drive WAA and build a more sturdy scandi block 

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    Posted
  • Location: South Ockendon, Thurrock, SW Essex
  • Weather Preferences: Severe frosts, Heavy snowfall, Thunder and lightning, Stormy weather
  • Location: South Ockendon, Thurrock, SW Essex

    06_237_arctic10 Stratosphere temperatures Valid 03GMT Wednesday 26th December.png

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    Posted
  • Location: Shanklin, Isle of Wight
  • Location: Shanklin, Isle of Wight

    gfsnh-10-384.png?6

    I prefer the parallel version of things. I know it only shows temps on there but you can get a good idea of what is probably happening.  

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    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    A ceaseless train of depressions, either sliding or channel-running, would do nicely...:cold:

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

    What a brilliant post from Zac! I’ve experimented with similar techniques for geopotential height anomalies for example, and it works wonders on customer understanding provided some example number-rarity equivalents are also provided.

     

    Now then - these stratosphere model projections... if the stance that I and a few others hold regarding the tropical cycle being suppressed and held back too much prove accurate, then the best charts will be yet to come as the wave-2 impacts are increased. GFSP already seeing this more now. GloSea5’s been producing very reasonable looking results for early January so it may as of writing this post be handling the tropical cycle a bit better than GFS and ECM.

    Those latter two adjusted the projected MJO amplitude up a bit today so perhaps the first sign of them catching on at last?

    Such an exciting time scientifically and hopefully for actual resulting weather by the middle of next month!

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