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Stratosphere and Polar Vortex Watch


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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
    13 minutes ago, Interitus said:

    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.

     

    Just to clarify, u1060 = 10hPa zonal mean at 60N?

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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

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    Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

    A few GEFS members really going for a major SSW now later this month

    u_65N_10hpa_gefs.thumb.png.0247e7a7b3f3c70dd8c918fa35f817ea.png

    0.5 GFS forecast going for the 0 line

    u_65N_10hpa.thumb.png.1cfe98318ac1fc7260c7494f6b57ac11.png

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    Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
    1 hour ago, northwestsnow said:

    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..

    If the vortex is weak enough (looks like it should be) then the warming and GPH rises should push across the N. Pole area from Siberia/E. Asia.

    I'm still feeling that the models may be under-doing the wave-2 component to this though; troughs still going too positively-tilted next weekend for my liking, reducing (or at least delaying) the progression of blocking highs toward Greenland. UKMO is close though.

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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
    43 minutes ago, Nick F said:

    A few GEFS members really going for a major SSW now later this month

    u_65N_10hpa_gefs.thumb.png.0247e7a7b3f3c70dd8c918fa35f817ea.png

    0.5 GFS forecast going for the 0 line

    u_65N_10hpa.thumb.png.1cfe98318ac1fc7260c7494f6b57ac11.png

    Shame you can't get the GEFS members archived anywhere (unless I'm mistaken?) as I'd really like to see that -30m/s member. :oldsmile:

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    1 hour ago, Nick F said:

    A few GEFS members really going for a major SSW now later this month

    u_65N_10hpa_gefs.thumb.png.0247e7a7b3f3c70dd8c918fa35f817ea.png

    0.5 GFS forecast going for the 0 line

    u_65N_10hpa.thumb.png.1cfe98318ac1fc7260c7494f6b57ac11.png

    What we need to see next (and this is a concern because the warming is moderating at 384 at 1mb on the 6z GFS) is those zonal winds to flatline for a significant amount of time at 0 or preferably below 0 m/s, im hoping for a split soon afterwards which would do this hopefully, my concern is with a displacement SSW, we might only have limited opportunity before the vortex returns to the pole.

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    Posted
  • Location: Bedford, 30m asl
  • Location: Bedford, 30m asl
    31 minutes ago, feb1991blizzard said:

    What we need to see next (and this is a concern because the warming is moderating at 384 at 1mb on the 6z GFS) is those zonal winds to flatline for a significant amount of time at 0 or preferably below 0 m/s, im hoping for a split soon afterwards which would do this hopefully, my concern is with a displacement SSW, we might only have limited opportunity before the vortex returns to the pole.

    Possibly....although looking at the images posted in here this morning (unlike the meteociel temperature only ones which always do the rounds in the model thread) the warming wave from Asia (presumably from an EAMT) is riding around the surf zone of the beaten-up and displaced vortex and is starting to take on that shape where it looks primed to break into the heart of the vortex in the following few days - if, and it’s a big if, that does happen, then it shouldn’t matter too much where the displacement ends up....because there probably won’t be too much of a vortex left to be displaced.

    I need to do some further digging in to this but timing wise, and looking at the shape of the temperature wave, this feels fairly similar to 2013 - I will caveat that though but saying I have had no time to analyse this yet.

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

    Possibly....although looking at the images posted in here this morning (unlike the meteociel temperature only ones which always do the rounds in the model thread) the warming wave from Asia (presumably from an EAMT) is riding around the surf zone of the beaten-up and displaced vortex and is starting to take on that shape where it looks primed to break into the heart of the vortex in the following few days - if, and it’s a big if, that does happen, then it shouldn’t matter too much where the displacement ends up....because there probably won’t be too much of a vortex left to be displaced.

    I need to do some further digging in to this but timing wise, and looking at the shape of the temperature wave, this feels fairly similar to 2013 - I will caveat that though but saying I have had no time to analyse this yet.

    Yes, i've been thinking it looks similar to 2013 for a while, yes i post the temp charts because that's what comes first, always the caveat of course that its the height charts that count wrt affecting the trop.

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    Posted
  • Location: Coniston, Cumbria 90m ASL
  • Weather Preferences: wintry
  • Location: Coniston, Cumbria 90m ASL
    Posted
  • Location: st albans
  • Location: st albans
    4 minutes ago, Dennis said:

     

    How accurate can gfs be at two weeks out re a burst of energy from the trop into the strat ?? IMO, too much of what Cohen tweets is based on gfs op runs at distant range .....

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    Posted
  • Location: Broadmayne a few miles north of Weymouth in Dorset
  • Weather Preferences: Snowfall
  • Location: Broadmayne a few miles north of Weymouth in Dorset
    17 minutes ago, bluearmy said:

    How accurate can gfs be at two weeks out re a burst of energy from the trop into the strat ?? IMO, too much of what Cohen tweets is based on gfs op runs at distant range .....

    Yes always fascinated me why an obviously educated man like Cohen uses the worst performing model of the top three to tweet about forecast vortex changes.

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    Posted
  • Location: Clayton-le-Woods, Chorley, Lancs
  • Weather Preferences: Snow
  • Location: Clayton-le-Woods, Chorley, Lancs
    1 hour ago, bluearmy said:

    How accurate can gfs be at two weeks out re a burst of energy from the trop into the strat ?? IMO, too much of what Cohen tweets is based on gfs op runs at distant range .....

    That's why I stopped following him on Twitter. 

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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
    54 minutes ago, Broadmayne blizzard said:

    Yes always fascinated me why an obviously educated man like Cohen uses the worst performing model of the top three to tweet about forecast vortex changes.

    Because it's free.

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    52 minutes ago, Broadmayne blizzard said:

    Yes always fascinated me why an obviously educated man like Cohen uses the worst performing model of the top three to tweet about forecast vortex changes.

     He doesn't have access to the full ECMWF dataset and obviously the UKMO doesn't go that far - their ens suite is strictly met office in house.

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    Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

    I have wondered sometimes if Cohen's tweets are a bit too sensationalist and not erring on caution enough. The amount of times he promises good things form the stratosphere re: warming and snow extent throughout every winter. As much as I appreciate he knows his stuff and is an expert in his field, he is obviously cold ramper, though not to the extreme of Joe B.

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    Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
    2 hours ago, ALL ABOARD said:

    Surely a split wouldn't be to far away if these verfied... 

     

    Screenshot_20181210-120437.thumb.jpg.f465cbcd4d6539e8a5e1f45a311725f2.jpgScreenshot_20181210-120615.thumb.jpg.13c5a3f11c67354357b50c4bc4f010d8.jpg

    That just shows the extent of warming and not the vortex profile. And it is indicative of a displacement type warming from wave 1, not a wave 2 type split event. And it would still be a bit short. When looking back previously at wave 1 type SSW's there are two types. One, where the vortex loses power, dis[places off the pole but quickly regains strength and recovers the pole position in a relatively short time. The other is rarer and occurs when the warming is so significant that rather than just getting displaced, it is completely destroyed and it takes it a long time to rebuild. It is the latter type of displacement that will have the greater chance of a significant tropospheric response.

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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    1 minute ago, chionomaniac said:

    That just shows the extent of warming and not the vortex profile. And it is indicative of a displacement type warming from wave 1, not a wave 2 type split event. And it would still be a bit short. When looking back previously at wave 1 type SSW's there are two types. One, where the vortex loses power, dis[places off the pole but quickly regains strength and recovers the pole position in a relatively short time. The other is rarer and occurs when the warming is so significant that rather than just getting displaced, it is completely destroyed and it takes it a long time to rebuild. It is the latter type of displacement that will have the greater chance of a significant tropospheric response.

    Nice to hear from you Chino,

    Not sure if thats what i wanted hear mind.

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    Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
    On 09/12/2018 at 08:43, 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?

    I would say that it is the other way around. Wave 1 displacements are perfect primers for weakening the vortex followed by a wave 2 chop. The wave 1 SSW's as you said are poor for NW Europe and that will still probably be the case without another wave 2 following on behind, and this is where I would be looking for  strat PV destruction.

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    Posted
  • Location: Netherlands
  • Location: Netherlands
    2 hours ago, snowking said:

    Possibly....although looking at the images posted in here this morning (unlike the meteociel temperature only ones which always do the rounds in the model thread) the warming wave from Asia (presumably from an EAMT) is riding around the surf zone of the beaten-up and displaced vortex and is starting to take on that shape where it looks primed to break into the heart of the vortex in the following few days - if, and it’s a big if, that does happen, then it shouldn’t matter too much where the displacement ends up....because there probably won’t be too much of a vortex left to be displaced.

    I need to do some further digging in to this but timing wise, and looking at the shape of the temperature wave, this feels fairly similar to 2013 - I will caveat that though but saying I have had no time to analyse this yet.

    Hi, you can the archive over here: http://www.meteociel.fr/modeles/archives/archives.php?day=10&month=1&year=2013&hour=0&type=era&map=5&type=era&region=nh&mode=0

    In 2013 we saw a split SSW. 

    archivesnh-2013-1-5-0-4.png

    archivesnh-2013-1-10-0-4.png

    archivesnh-2013-1-15-0-4.png

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    Posted
  • Location: st albans
  • Location: st albans
    15 minutes ago, chionomaniac said:

    I would say that it is the other way around. Wave 1 displacements are perfect primers for weakening the vortex followed by a wave 2 chop. The wave 1 SSW's as you said are poor for NW Europe and that will still probably be the case without another wave 2 following on behind, and this is where I would be looking for  strat PV destruction.

    how useful would an amplified trop Alaskan upper ridge in week 2 be ……………………….  

    Edited by bluearmy
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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    20 minutes ago, chionomaniac said:

    I would say that it is the other way around. Wave 1 displacements are perfect primers for weakening the vortex followed by a wave 2 chop. The wave 1 SSW's as you said are poor for NW Europe and that will still probably be the case without another wave 2 following on behind, and this is where I would be looking for  strat PV destruction.

    So, currently not great then?

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    Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
    8 minutes ago, bluearmy said:

    how useful would an amplified trop Alaskan upper ridge in week 2 be ……………………….  

    That was going to be my next point, because it is exactly what we want to see.......

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