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Technical General Stratospheric Observations

Discussion in 'Systems & Severe' started by crikey, Jul 6, 2019.

  1. Adaminaby Angler

    Adaminaby Angler One of Us

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    Grytviken, South Georgia; 4 m AMSL (coastline); 54° S; that Thursday looks blasted cold!

    [​IMG]
     
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  2. Kino

    Kino Early Days

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    Well (a) is there a split happening; and if so (b) what may be the outcome? I don't see any real mega cold weather forecast; but assume it there would be some lag time between the split and associated impacts?
     
  3. snowbarbie

    snowbarbie Hard Yards

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    [​IMG]
    I think the distortion in the tropospheric vortex is reflected in the core of the longwave but cold outbreaks still have to follow the ridge lines up as it rotates - and it can seem fickle where they peak. Overall, thickness values to 500hpa seem a bit lower at the moment - that's not a verified obs..just my impression...away from path of outbreaks(Tas&NZ look good) maybe there is a degree or three in it?
     
  4. crikey

    crikey Addicted

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    Hi #Kino
    according to my personal assessment based on the criteria l have used in this forum topic, the split in the polar vortex happened on 7th July 2019.
    The immediate consequence for me was the temporary disintegration of the sub polar vortex and the contraction of the cold polar temps' toward the pole.
    We know that in the NH, after a polar vortex split, a meandering sub polar jet and associated cold outbreaks occurs about one week after the split.
    This is situation is the SH polar vortex and has different behaviours from the Arctic region because of the land/ice mass at the centre of the south pole and the massive cold ocean surrounding the Antartic .

    I am keeping an open mind regarding what could happen regarding cold outbursts from the Antartic as a direct result of polar vortex split.
    The best bet would be to look at past history
    2002 being the last vortex split l am aware of currently. I will check that out Asap.
    So far l have nothing to suggest that the cold fronts coming through VIC and NSW this week have nothing to do with the vortex split.
    I will monitor the jetstream, AAO, synoptic patterns etc over the coming week and place my observations here.
    What l am saying is l am unsure at this stage.
    The AAO is going neg' this week but that is not unusual as it does that any way on a quasi cyclical basis.
    I will observe and record.......I better get on to it..
    Thanks for your question..
     
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  5. crikey

    crikey Addicted

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    yes. #snowbarbie
    Forecast this week showing some nodes appearing.
    The nodes around the pole move in and out of organised -dis organized phase regularly as part of the normal nodal cycle
    The forecast showing the sub polar lows quickly re organising in the coming days into a symetric
    pattern..
    Of note is that the polar vortex dipole formed during a disorganized phase.
    I will post some pics',of the next organized phase.
    The other thing l will post is the return of the sub polar jet stream. I will use ACC g cormboth these upcoming observations
    so you can look anytime
     
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  6. crikey

    crikey Addicted

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    OK..continuing.. More on the aftermath

    2 days after dipole polar vortex formed

    still no sub polar jet


     
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  7. crikey

    crikey Addicted

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    Hmmm ok.
    Just recapping.. Around the 20th May according to 70hpa temps' There was a substantial warm anomaly.in SH
    Now ..70hpa is not the stratosphere it is higher up. The stratosphere is 200hpa.
    So not just a stratosphere warming

    I know that the warm anomaly went down to at least 200hpa because we have seen the warm anomaly blog traversing around the sub polar latitudes in the animations on page one.
    So this was not just a stratospheric warming blob ,,it extended at up least to 70hpa

    some sticky notes

    The first possible connection to our surface weather.
    Around the 27th May when 70hpa warming was established.
    I found in my jetstream notes that the sub polar jet looked weak in wind strength and the sub tropical jet was Highly zonal

    The warming in the upper layer affecting the sub polar jet possible.?and making the sub tropical jet zonal..straight.

    Now we know how the sub polar jet affects our southern weather.

    and how a zonal sub tropical jet affects our mid latitude weather.

    Now we have connections between this circling warming blob and jet stream patterns.
    It seems the sub polar jet has been weakening for some time, since late MAY but mostly in speed. not shape.
    I believe the 7th July vortex dipole coincided with the sub polar jet disappearance.



    JUNE ..
    persistent pos AAO and associated weather in the south
    Decline in snow

    zonal sub tropical jet airh boring dry weather the mid latitudes , coastal exceptions
     
  8. snowbarbie

    snowbarbie Hard Yards

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    I'm not sure why bom don't have a 300hpa option - that's what I usually look at. The polar jet can merge with the subtropical. There are signs of an independent polar jet at ~60e,~160w, ~90w and ~20w

    [​IMG]
     
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  9. crikey

    crikey Addicted

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  10. crikey

    crikey Addicted

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  11. crikey

    crikey Addicted

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    Yes the GFS display is different to ACC g.I am not sure why. The use of different definitions when plotting perhaps.

    I have used ACC g for 6 years and have many snaps of the jetstream patterns from the ACC interface.
    I use the same model for consistency when studying patterns.
    I can only say l record the pattern, (zonal and meridonal ) and the contraction and expansion north or south
    I find the pattern on the 7th July, the most intriguing based on my years of obs' in ACC 200hpa and especially for winter..July
    and in hindsight also the extended period of zonal flow of the Sub polar jet.
     
  12. crikey

    crikey Addicted

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    Ah ha .. I think GFS records ONLY the streaks. That is the highest speed wind trails.
    where as ACC shows the complete wind stream profile plus the streaks superimposed

    so .. what GFS may show is decline in the number of higher velocity streaks at sub polar latitudes.
     
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  13. crikey

    crikey Addicted

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    Just going back to page one.of this thread on sunday.
    #POW_hungry,posted a 10hpa temp profile
    Could you provide a link 'pow'.,There is a strong anomaly appearing below from the diagram on your post and l want to know what that red spot represents?

     
  14. crikey

    crikey Addicted

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    9th July 2019 . SH surface synoptic.
    Westerly belt contracted south.
    AAO was neutral at approx' minus 0.5 on the 7th JULY.
    Forecast is for steep decline until the 15th JULY with considerable consensus from the ensemble
     
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  15. snowbarbie

    snowbarbie Hard Yards

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    Very confused...can you possibly clarify...
     
  16. crikey

    crikey Addicted

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    Thanks for your interest #kino. I will check out your find and documentation on the 2002 polar vortex split tomorrow

    Here is the AAO index during the event
    Highly positive in June and breaking that trend commencing July 4th for a negative dive. Forecast to be a steep one.
    Not unusual.,There was a steep dive back May 2019 .From 10th to 20th May..
    Not convinced the AAO,index fully reflects what happened in the upper layer warm patches over the polar and sub polar region
    https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao.fcst.gif
     
  17. crikey

    crikey Addicted

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    [​IMG]
    I didn't realise the stratosphere went that far up and encompassd such a broad area. Thanks for that correction.
    So when we talk about the 10hpa to 200hpa range , we are talking about.. the stratosphere.
    So a stratospheric warming is quite a deep phenomena vertically. But only a blob' horizontally. So that might look like a 3D cylinder perhaps....
     
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  18. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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    To tag use the @ symbol @crikey . Only just saw this.
    JMA monitors it best HERE. A brilliant tool to see the disparity and volatility in the PV's South Vs Northern.

    Check the latest comparison between Strat & lower strat.
    Perhaps some decoupling with the dilation of the deformation of the PV.
    30hPa showing a brief, recent cooling trend
    [​IMG]
    10hPa showing a brief, recent warming trend
    [​IMG]

    Latest Temp changes:
    [​IMG]
     
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  19. snowbarbie

    snowbarbie Hard Yards

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    Interesting find here. Following extract from abstract at
    https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017JD027648
    Might need to use address line in a search. Unfortunately cant get access to full paper - though if anyone finds a way please post it.

    "It is found that stratospheric variability is more sensitive to the temperature distribution in the lower stratosphere than in the upper stratosphere. In particular, a cold lower stratosphere favors a strong time‐mean polar vortex with a large daily variability, promoting frequent sudden stratospheric warming events in the model runs forced with both wavenumber‐1 and wavenumber‐2 topographies. This sensitivity is explained by the control exerted by the lower‐stratospheric basic state onto fluxes of planetary‐scale wave activity from the troposphere to the stratosphere, confirming that the lower stratosphere can act like a valve for the upward propagation of wave activity."

    In current context - the lower polar stratosphere is forecast to cool further and if the proposition outlined above is correct - seems to imply the lower stratospheric "valve" might be expected to be more open than not.
     
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  20. In a nutshell the current stratospheric warming causes high lat blocking This in turn sends deep troughs over the se. Would Jane like to input here.
     
  21. Ozgirl

    Ozgirl Part of the Furniture Ski Pass: Gold

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    Jane Bunn Jane?

    @janesweather
     
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  23. Ozgirl

    Ozgirl Part of the Furniture Ski Pass: Gold

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  24. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    She’s quite the busy person.
     
  25. Ozgirl

    Ozgirl Part of the Furniture Ski Pass: Gold

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    yep - was just saying she might not respond in a timely fashion!
     
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  26. Ozgirl

    Ozgirl Part of the Furniture Ski Pass: Gold

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    I just tagged her on twitter!

    I wanna know if she thinks it will snow MORE. Priorities.
     
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  27. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    You could try tweeting her. She checks that more regularly than here.
     
  28. Ozgirl

    Ozgirl Part of the Furniture Ski Pass: Gold

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    See above!
     
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  29. crikey

    crikey Addicted

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    thanks for that link and graphs @POW_hungry
    Could you tell me what those red patches represent on the 10hpa weekly temps' you posted?

    The 50 hpa warm pool peaked at around 20th June ..2019 and noticing from that weekly temp' map there is a possible warm anomaly pool growing in red ? on that 10hpa map commencing on the 28th June and is still enlarging on the 9th July..
    Could the warm pool at 50hpa 20th June, risen to the 10hpa layer a week later on the 28th june and is still rising on the 9th July.


     
  30. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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  31. DiscoStuAU

    DiscoStuAU One of Us Ski Pass: Gold

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    I'd try sending her a message over her website - I asked her a question back in May and she responded to me only a day after I sent it. Wasn't expecting a reply at all, let alone a quick one. She has an "ask Jane" button

    Failing that my fiancé sees her almost daily at the Woolworths he manages so he can ask her directly lol. Jokes of course...
     
  32. Waiting on Hanna Hattard to respond viva twitter.
     
  33. crikey

    crikey Addicted

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    OK. Thanks for that..@POW_hungry..
    A hot pool rising. Reminds me of a chimney.
    A 25deg anomaly is a substantial chimney.
    Evidence that the source of warming came from the' bottom and rising ' and not top down.

    This graph you posted is useful in that it indicates the temp' disturbance at 30hpa happened first week of MAY 2019 .
    If the disturbance came from lower levels and moves upward, it might of taken a week or two to get to get to 30hpa.
    So the cause of the warm disturbance could have been caused by something at lower altitude in say mid April.
    Any decent volcanoes in SH around mid April 2019.? or what else ?
     
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  34. TBH all i see is a blocking that may be gone in the fortnite.
     
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  35. snowbarbie

    snowbarbie Hard Yards

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    I think that warming is the result of more recent wave activity - it's located in a different sector
     
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  36. Title is wrong the PV is not split. Should be S-H PV.
     
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  37. crikey

    crikey Addicted

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  38. crikey

    crikey Addicted

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    yes @snowbarbie
    that looks like a very interesting read and very pertinent. It uses a simulation model for both the NH and the SH
    I would suggest $7 cor 7 hours read is a good buy.
    Not sure about copyright and quoting from the research paper to the forum though
    I was particularly excited and your highlighted finding.

    "It is found that stratospheric variability is more sensitive to the temperature distribution in the lower stratosphere than in the upper stratosphere. In particular, a cold lower stratosphere favors a strong time‐mean polar vortex with a large daily variability, promoting frequent sudden stratospheric warming events in the model runs forced with both wavenumber‐1 and wavenumber‐2 topographies. This sensitivity is explained by the control exerted by the lower‐stratospheric basic state onto fluxes of planetary‐scale wave activity from the troposphere to the stratosphere, confirming that the lower stratosphere can act like a valve for the upward propagation of wave activity."
    ........
    It fives us hints on which stratosphere anomalies to observe... the lower stratosphere..which is ..200hpa? 100hpa?
    from say April to July 2019
     
  39. crikey

    crikey Addicted

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    @snowbarbie
    Can you elaborate l would like to hear your thoughts on this?
     
  40. crikey

    crikey Addicted

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    That would depend on your defnition of polar vortex.
    @snowbarbie posted an essay on this topic critiqing the medias' use of the term as well as researchers.
    The criteria has changed over time. A researcher would define the 'polar vortex' at the start of their research

    The definition l have used is the wind stream profile,in the stratosphere 70hpa over the south pole extending to and polar region
    using nullschool windstreams,
    and
    ,ACC g, 200hpa wind profile and surface synoptic
    There were 2 vortices vertically stacked on the 7th July and may still be there tonight .?

    and your criteria?
     
  41. crikey

    crikey Addicted

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    Any theory is worth investigating. Could you provide a link for the blocking high you have observed
    That is why l am taking screen shots of the SH surface synoptic
     
  42. crikey

    crikey Addicted

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    Thanks for that link it looks great.
    Got anything for temperature anomalies for the surface of Antartic. I have heard rumours on AWF that the Antartic has warm anomalies since the stratospheric temp' disturbance in JUNE.. Needs looking in to.
     
  43. snowbarbie

    snowbarbie Hard Yards

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    I can try to put something together but it may take considerable time.
    I was responding to
    Perhaps the easiest way to explain this - the stratospheric lapse rate is the opposite of the troposphere's - temperatures tend to rise as elevation is gained - this means it is very difficult for air parcels to rise. The stratosphere is usually described as stabily stratifed. I guess you would need to know what the temperature of the warm anomaly was in relation to the surrounding stratospheric environment to know how far air parcels might go but it's probably not going to be far.
     
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  44. crikey

    crikey Addicted

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    yes. @snowbarbie , l would be definately interested in your findings. My knowledge of convective parcels is limited but l realise that l have to get out of my comfort zone and explore this , otherwise it beomes hard to assess volcanic incluence in the stratosphere on this current warming event and 'polar split'
    or
    a more recent disturbance from something like the run of very strong high pressure cells
    or
    planetary wave activity ,which l am waiting on #jwintewrmix or others to elaborate on
    My aim is to keep on collecting data currently as the warming subsides and the sub tropical jet re strengthens.
    Then when we have data we can take as long as we like to diagnose causes and effects
    cheers
     
  45. crikey

    crikey Addicted

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    I have been looking for a good site on wind anomalies for the polar region and sub polar region, say to 0-40s

    If you want to prove that there has been a weakening in June 2019
    and then breakdown of sub polar jetstream , 200hpa,first week in July 2019 ...as a consequence of the stratospheric warming event.
    You need wind stream and speed anomaly charts

    I had a look on google which was unusually not helpful.
    So . any links?
     
  46. snowbarbie

    snowbarbie Hard Yards

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    I think you were speaking about the period on the TCC chart below between about 1 - 16 June - at least I think it's the activity from that period which best fits the obs behind your comments.
    [​IMG]



    There are two spikes in EP flux during that time.

    Eddy height anomalies for the 1-5 June(the first spike) are shown below at about 60e
    [​IMG]


    Eddy height anomalies for second spike(9-11June) are about 120w

    [​IMG]
     
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  47. crikey

    crikey Addicted

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    I can clearly see some strong anomalies there in what you have posted above.
    I am not able to comment because those terms are completely alien to me.
    TCC chart?
    E-P flux?
    Eddy height anomalies?

    Do you have the link to your source so that l can read the 'about' section.
    I am happy for a tutorial...if you have time .

    Great you have posted the data . Can. 'chew it over' at a later date.
     
  48. crikey

    crikey Addicted

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    Sub polar jet is still AWOL , 4days after the vortex split.( dipole lows formed.)
    Still can't find wind anomalies for stratosphere 200hp? can anyone help

    Anyway thanks to 'jasminestorm' from AWF who is also documenting this event.
    Gave me link and l tripped over this jetstream speed diagram
    showing a ....side on view..... of the sub polar jet missing .
    There are a couple of tiny streaks and one is assisting in the cold pool excursion over VIC currently.
    But otherwise 'yarda zilch'

    source
    https://climatereanalyzer.org/wx/DailySummary/#ws250-snowc-topo

     
  49. Ret-ro

    Ret-ro One of Us

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    noted
     
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