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Stratosphere watch 2020-21

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Comments

  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Looks like this ship has sailed. Easterlies didn't make it down below 100 hPa in the end, despite all the tweets.

    540054.gif


  • Registered Users Posts: 16,550 ✭✭✭✭nacho libre


    So what you are saying is there will be no further impacts on the troposphere from the SSW on January 5th. What we have seen is the extent of it

    Will the tweeters acknowledge this. It seems some of them hopecast and hype things up to get more clicks.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    So what you are saying is there will be no further impacts on the troposphere from the SSW on January 5th. What we have seen is the extent of it

    Will the tweeters acknowledge this. It seems some of them hopecast and hype things up to get more clicks.

    We haven't seen any real effects on the troposphere at all anyway. It looks like the stratopsheric polar vortex will try to reestablish itself over the next week, but then tentative signs of a another warming over east Asia towards the end of the month.

    The second part, you've answered your own question. SSW clickcasting is big business.


  • Registered Users Posts: 15,944 ✭✭✭✭Villain


    Ah many share the ups and downs to be fair and I think many are interesting, obviously some just post hype but just like anything else weather sites and accounts come and go over the years :D

    https://twitter.com/PvForecast/status/1351642631525298177?s=20


  • Registered Users Posts: 688 ✭✭✭bazlers


    I would take each model produced as just entertaining until they get a better understanding as to how this effects the normal Joe Soap going about his business on the ground.
    Judah Cohan who I would class as knowing his stuff infairness opening admitted to not knowing on some models what this actually will result in... (Id have more respect for him for saying that) only to entertain him.


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  • Registered Users Posts: 16,550 ✭✭✭✭nacho libre


    bazlers wrote: »
    I would take each model produced as just entertaining until they get a better understanding as to how this effects the normal Joe Soap going about his business on the ground.
    Judah Cohan who I would class as knowing his stuff infairness opening admitted to not knowing on some models what this actually will result in... (Id have more respect for him for saying that) only to entertain him.

    It's the others who pretend to know, then don't acknowledge being wrong, are the ones I have in mind. There is one particular individual who blocks people if they start questioning him too much.

    As regards the SSW having no really effects on the troposphere, i think it has just not in a way that has benefitted us to date


  • Registered Users Posts: 599 ✭✭✭Captain Snow


    A very Very Long read....alot of Tea and Biscuits time

    But explains today how the SSW is now going to effect are weather going forward.


    https://www.severe-weather.eu/global-weather/polar-vortex-weather-winter-february-united-states-europe-fa/


  • Registered Users Posts: 16,550 ✭✭✭✭nacho libre


    So no deep cold for us based on that. I was hoping for a happy ending


  • Registered Users Posts: 599 ✭✭✭Captain Snow


    So no deep cold for us based on that. I was hoping for a happy ending

    The cold theme continues for us but no real 2010, 2018 etc for the time being.

    No storms etc.

    Alot of cold nights frosts etc.

    The position of the blocking is not predictable. We know its there.

    The ideal position is over Greenland or Scandinavia.

    We have to wait and see how it plays out.


  • Posts: 0 [Deleted User]


    So no deep cold for us based on that. I was hoping for a happy ending

    Only because the cold is not 'available for transport' to our region
    That has more to do with the southern blocking than the scamstrat
    We spend lot of time talking about northern blocking but none about southern blocking which blocks out the cold


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  • Registered Users Posts: 16,550 ✭✭✭✭nacho libre


    Yes, the cold is there but is out of reach and more likely to stay out of reach based on that article.I would love to know if the persistent iberian heights are somehow a consequence of the strat event. It seems we have lows meandering around that end up propping the heights, then just when it looks like the high might go wandering it gets flattened. I will know for again if we don't see a proper split arising from a ssw it's akin to a dog chasing its own tail trying to get proper cold in here.


  • Posts: 0 [Deleted User]


    The answer to that question is nobody knows
    Science can't sometimes tell us tomorrow's weather, and always has trouble with 5 days plus so expecting scientists to do anything other than muse regarding strat warms etc is a pipe dream in my opinion
    We're in another winter without a widespread snow event again
    No point counting last w/end as it was temporary and affected maybe 30% or less of the country
    We are better than most winters so far in the sense that at times we are close enough to marginal that hilly spots and some flukey areas do see bits of snow


  • Registered Users Posts: 13,477 ✭✭✭✭sryanbruen


    First post here in a while. The major sudden stratospheric warming (SSW) happened in early January with an estimated central date of 5th January when the zonal mean zonal winds at 10hPa 60N went into reversal from westerly to easterly. This central date is to be confirmed in reanalysis towards the end of the season or next winter. It was primarily wave-1 driven and the stratospheric polar vortex (SPV) was displaced from its habitat. Through succeeding warming events in mid-January, wave-1 splitting did occur with further reversals but this did not evolve into a wave-2 major SSW event. All of these constitute as 1 major SSW event as for multiple major SSW events for historical consistency and various reasons, there must be a period of at least 20-30 consecutive days with positive zonal mean zonal winds i.e. westerly.

    mhmv34S.jpg

    This has been a downward propagating SSW (dSSW) event going by the below cross section with clear negative Northern Annular Mode (also known as the Arctic Oscillation) in the stratosphere in early January associated with the major SSW event.

    What may make it more difficult or confusing at first to tell when there was downward propagation exactly, using this data specifically, is how there was already blocking in the Arctic in the troposphere pre the SSW event and during it. However, the -AO has peaked during this cold spell giving away to extreme negativity of the index and extensive blocking over the Arctic. The second time-series I have given shows the propagation more clearly as it's the geopotential height anomaly for this year so far. There is a clear smooth propagation occurring from early January right at the top of the stratosphere (1-10hPa), in the lower stratosphere through mid-January (30-50hPa) and down to the troposphere (between 70-400hPa) coming up to late January.

    The GFS is forecasting a readily strengthening SPV through the rest of February which you would expect as the very weak stratospheric polar vortex cannot go on forever and typically with major SSW winters, there is a later than normal final stratospheric warming (FSW) when the zonal mean zonal winds reverse to easterly for summertime before reforming in late August with the mean date being April 15th.

    There is the likelihood for the -AO to significantly pay back a touch next week but there is no sign of going into positivity for the foreseeable future, at least on current model runs. Therefore, we should expect further blocking around the pole, just not as extensive or as extreme as we see now on synoptics at the moment.

    kPEoVk9.png

    NFUb7I3.png


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