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skatefan

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  1. skatefan
    Yes, Is it correct to state that It requires more energy to disturb a strong vortex but when it happens the effects will be more spectacular? And: a weakened vortex is easier to disturb but the effects are less? There is a lot in between these.... On the other hand: a strong trop-jet (caused by a strong start PV) creates more energy and chances for MT's and warming are bigger. Its all a matter of balance but Ideally it would be a weakened strat PV and relative strong trop-jet?
  2. skatefan
    That's the point I tried making yesterday evening. The Skandi-high is troposferically holding on due to stratosferical weakening and displacement. Both Gfs and ECM support this up to T240. Chio: in line with your image of two dancers: the troposferic one leads the dance here because the stratosferic dancer allows it or is not able to the take the lead. I expect the first cold spells late nov/early dec. It won't be "big-time" but the first dance sets the tone...
  3. skatefan
    I think the developments arround T240 are quite interesting: both GFS and ECMWF predict ridging at 500HPA in the direction of Iceland/Greenland: This introduces a cold spell from the North. http://www.wetterzentrale.de/pics/Recmnh2401.gif https://max.nwstatic.co.uk/gfsimages/gfs.20141115/18/240/npsh500.png the, at that time reinforcing, stratosferic vortex also positions in that place: https://max.nwstatic.co.uk/gfsimages/gfs.20141115/18/240/npst30.png I don't know but it looks to me that at this stage the (shattered) troposferical vortex determines the development of the stratosferic vortex and not the other way. .
  4. skatefan
    Hm, Do I read it correct in this graph that the wave-1 activity in oct. last year was also above average (even way above the upper variancy)?
  5. skatefan
    yeah, that's truth but what I mean is: it will land somewhere either displaced or splitted. Can we say something about the effects that specific "landing-places" have on the tropospheric vortex and thus on the effects on the winter-weather? I know I am placing a big question and I know that understanding the behaviour of the stratospheric vortex is still in early investigation but in-the-end its is all about the effects this has on the troposherical conditions!
  6. skatefan
    Thanks Chio for your excellent baseline posting! I am following this thread for a couple of years now and I am learning a lot! What still puzzles me very much is the positioning of the stratospheric vortex in wintertime. Clearly a strong vortex will be highly central to the noth-pole but when weakened, displaced or even split, where will it "land"!? And what effect will that position have on the troposferic position. It seems to me this is a question we should be investigating to understand the stratosphere/troposphere coupling and effects on tropospheric blocking?
  7. skatefan
    Any thoughts on these questions? I know Chio mentioned that the troposferical vortex above Canada is getting disconnected from the stratosferical one but the amount of energie this is moving across the atlantic currently appears to me as a strong troposferical polar Vortex. The 500 Hpa models show that HP intermittently tries to move north but is continously "ironed" away in the coming days/weeks. I am still very much trying to understand whether and how this troposferical condition relates to previous stratosferical events. My question about the models is related to that: maybe they dont model/calculate those coupling processes at all... Then I know what the value of model-predictions is.
  8. skatefan
    Talking about lag-times: on the basis of what is written in this thread it is clear to me that there is a lag time between the occurrence of a SSW and the stratosferical vortex response (displacement, split etc.). But I am still struggling with the lag time between stratosferical vortex changes and the troposferical effects they have. I understand that there are a lot of processes involved (coupling is discussed in this thread) there but there must be a lag. It looks to me that the current restoration of the stratosferical vortex almost instantaneously has an effect on the enormous troposferical W-E transport of LP-energy across the Atlantic. It might be a coincidence with historical stratosferical events but I would like to understand this. Another question: Do (and to what extent) the weather-models take the physical interaction (including SSW's) between stratosphere and troposphere active into the modelling account or are they purely based on historical data?
  9. skatefan
    So, to be sure if i understand you correctly, the warming of the stratosferical Canadian vortex at 10 hpa creates the un-coupling of the troposferical one?It still leaves me with the question why the movements of the stratosferical vortex and the troposferical movements seem to be happening simultaneously.
  10. skatefan
    Dear Chio, thanks for all your interesting and exciting posts. I think that you contributed a lot to the knowledge about stratosferical processes and the the prediction and effects of SSW's! My compliments for your work here. I am still struggling, though, with the developments of next week. You state that the stratosferical canadian vortex (30 hpa chart) is moving to the atlantic and is trying to move to/merge with the siberian vortex. Why is that movement so strong with a heavily weakened vortex? Troposferically (500 hpa) i see the same movement: a lot off LP-energie comes across the atlantic and is moving to Skandinavia, the Jet is moving further North. It suggests that those stratosferical and troposferical movements are coupled. They coincide at least in time. You wrote in your post that due to continued warming of the stratosferical vortex above Canada, the troposferical one brakes free. Am I overseeing something or is this just coincidence. I am eager to learn so please forgive me my possible stupid question.
  11. skatefan
    I think GFS is supprting your theory. On the 500 Hpa today the (both 12Z and 18Z) western circulation will be, due to the Greenland HP, squeezed and somewhat forced a lower path. What puzzles me is the Skandinavien High: will it stay or will it go: is there any indication from the stratosferic movements?
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