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chionomaniac

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Everything posted by chionomaniac

  1. chionomaniac
    That is a really poor analogy, Gary. Weather enthusiasts are always going to be more interested in the rarer extremes in the same way that train spotters would be more interested in rarer engines. No one wants to see death and destruction but we all like to witness the power of nature up close.
  2. chionomaniac
    I could write the below about many posts that I have read in this thread today, but unfortunately for you skull you have posted at the wrong time so that I can use your post to illustrate a point ( and for that I apologise). And the point is that if you have nothing to say, then do just that, rather than filling this thread with crud. Posting is a privelege - not a right for you to be able to show how disconnected your fingers are from your brain. Please (and this is aimed at a significant minority- not the majority) remember that before hitting the 'post' reply button. Thank you to all in that minority.
  3. chionomaniac
    One good thing. Thankfully it is half term next week, and there will not be the usual school run or children walking to school at the worst time for the strong winds on Monday morning. I am off from work too and will be keeping mine indoors. I won't even be driving down to the coast for photo opportunities!
  4. chionomaniac
    Nothing can be ruled out, John, but when looking at all likelihoods it is extremely unlikely to get a SSW in November. Remember, to achieve a technical SSW we need to see mean zonal mean winds reverse at 10 hPA at 60ºN. Even in Nov 1996 (which is sometimes reported as a SSW) the mean zonal winds never reversed - and this was a eQBO year. What can possibly occur though is tropospheric wave breaks into the lower strat similar to 2009. Again another tall order. SSW's have occured later in the season in some close matching years though and one of my favourite analogue winters for this winter is 1978/79. That year a CW and SSW were reported. The forecasted increase in vortex strength for November was actually something that I was expecting to see. The Asian MT is such a significant one though that we need to keep an eye on whether there is any lower stratospheric vortex effect. Autumn 2009 showed us that the lower stratospheric vortex is vulnerable to tropospheric attack before the main bulk of the polar stratosphere has cooled sufficiently and the upper vortex strength transfers its power downwards towards the trop.
  5. chionomaniac
    I think that the met office tweet to Tom suggested that the criteria aren't met for a sting jet at the moment, but I don't think that it can be ruled out completely 2+ days away. There are certainly some parameters that do meet the possibility of a sting jet, so it is a bit early to rule it in or out.
  6. chionomaniac
    One has to think that with such a prolonged torque that it would be very surprising not to have some stratospheric knock on effect. I would normally expect to see some type of increase in wave 1 activity as a result and yes we have seen some, but perhaps a bit more than this could be expected.
  7. chionomaniac
    No definitely not - we may miss out on the calibre of posters such as Recretos, Sebastiaan and anthonym and others if that is the case. So we need to have it open but perhaps we will need stricter moderating to prevent going off on a tangent.
  8. chionomaniac
    I don't think that we need to limit posters SSIB- rather posters should make sure that what they are posting is relevent to the thread and not self serving their own agenda. After all, we are all here to increase our stratospheric knowledge and no-one should be excluded from that. Will be giving more detailed thoughts before the end of the month - but I think that the latest forecasts are more in line with where I expected the strat to be earlier in the month. Still sticking to the idea that the vortex will increase in strength throughout November and that this may teleconnect to a strong 500 hPa Atlantic Ridge going by previous years by mid November.
  9. chionomaniac
    Yes, I agree with this which is why I asked for it to be kept on topic. I guess that it is a victim of its own success!
  10. chionomaniac
    And perhaps it is time for the link to the solar activity and October storminess to be discussed in a thread of it's own. After all, I can find a link to justify the jet stream powering up through increased seasonal baroclinicity coinciding with a poleward surge of negative AAM leading to an increase in mid/high latitude westerlies without even looking at the solar activity.
  11. chionomaniac
    Neil, surely it is better to go with the opinion that even though other forecast storms have failed to materialise quite as expected and modeled, it is better not to assume that this will be the case this time. In that way not only do you get your point across, but you also respect the fact and other posters concerns, that this could be a potentially dangerous storm should the modeling be correct at this point. Just as well that you are not the chief forecaster!!
  12. chionomaniac
    I think that it is too soon for a Canadian warming and certainly for a SSW - the posts above from anthonym and myself were in response to this possibility. If you look at the 1hPa zonal mean wind forecasts for day 10 then you can see that the forecasts are suggesting that we will reach over 50m/s at 60N - that is getting nearer the 80m/s that we will see at max vortex conditions in the heart of winter - so certainly no negative effect there. There is a negative mean zonal wind anomaly created by this wave 1 activity and what will be interesting will be to seee if this propagates down the stratosphere towards the trop like 2009. http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_UGRD_ANOM_ALL_NH_2009.gif If so then we could see a tropospheric affect towards the end of November - perhaps coinciding with a poleward pulse of positive AAM, before the positive mean zonal winds re emerge in December. Now that really is conjecture!
  13. chionomaniac
    ECM T+126 wind fields
  14. chionomaniac
    If you push your finger on a balloon and it doesn't pop and you take your finger off then the balloon will resume its former shape straight away. It appears that the vortex does this as well, but strengthens as well - especially in the cooling phase. Cirus has demonstrated this in his post above with the positive NAM response to the weak wave 1 activity.
  15. chionomaniac
    Welcome Cirus and thanks - this thread is truly international! I am happy to say that your English is a lot better than my French! We may see that period of Vortex Intensification as the wave 1 activity seems to have reinforced the vortex rather than weaken it - the end of the month forecast at 10 hPa shows the vortex to be strengthening as one would expect.
  16. chionomaniac
    Yep, but its faded as its travelled north.
  17. chionomaniac
    Interesting radar characteristics of the storm south of Cork. Supercell? It may clip SW Ireland.
  18. chionomaniac
    I agree with lorenzo, thanks forecaster for a wonderful technical description of the types of wave that we refer to. And with the help of this linked site (thanks Tony for the link) we can see the two types of wave that are responsible for SSW's. The first link is from a SSW from Jan 2010 and shows a wave 1 type SSW. As can be seen from the animation on the left there is one peak and one trough up until the moment that the vortex was overcome. We call this type of SSW a displacement SSW, because the wave activity displaces the centre of the vortex from the pole. http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2010_01_30.gif The second animation is from the previous year and shows how a standing 2 wave pattern created a SSW late in January 2009. This type of SSW is known as a split type SSW because the waves split the vortex in two. http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2009_01_28.gif The 2009 event was strong enough to create an immediate effect in the troposphere and the effect of the waves on the potential vorticity of the stratospheric vortex is quite pronounced and can also be viewed here. http://eoimages.gsfc.nasa.gov/images/imagerecords/36000/36972/npole_gmao_200901-02.mov Hopefully these visual aids can complement forecaster's excellent narrative above.
  19. chionomaniac
    Fantastic post, Recretos. You are most definitely the future of this type of work and it is wonderful having your contributions to this forum. Regarding the comparison of the mean zonal wind to the temperature difference between the tropical strat and the mid latitude strat, I supect that any correlation may be lost in the timeframes chosen - ie Oct - Dec for 10mb and Oct-Nov for 30mb. I wonder would there be a correlation if it was broken down by month to month and the differential was taken from 25N-25S and 90N-65N (not 25N-65N as you have chosen). I suspect that by using the temps from the mid latitudes and not polar temps that you may not have included the full differential, but nevertheless it is wonderful that you are able to produce these plots. I would agree that at this time of year that whatever is thrown at the strat from the trop it is in the rapid cooling phase and that the vortex will grow in strength. And we will need to see how cold the polar strat gets compared to climatological mean and the differential between that and the tropical strat. Which now leads me off to try and locate info on the tropical strat ozone levels and comparison to previous years.
  20. chionomaniac
    As I said, we will know more in a months time.
  21. chionomaniac
    Not necessarily at this point. We will know more in a months time.
  22. chionomaniac
    I meant to say yeaterday, but didn't get around to, that your modified November H500 analogue fits in very nicely with what I expect to see as well. I expect November to be characterized by a stronger PV though but with a strong Atlantic ridge also with the positive anomaly stretching towards the UK - and I have used completely different analogue years to formulate mine. However, December's anomaly chart differs completely - but if the November anomaly chart holds true then there will be the opportunity for cold snaps to develop around the back of the Atlantic ridge. Sometimes ( like now!) a southern Greenland based positive anomaly (ridge) doesn't deliver anyway and we actually need that positive anomaly to stretch down into the Atlantic!
  23. chionomaniac
    Thanks Phil though one has to know the average to know how far above or below we are. This is the site that I normally use but it hasn't updated since early September. http://acdb-ext.gsfc.nasa.gov/Data_services/met/ann_data.html However, I can see that the mean zonal winds for the end of October are around 22m/s and 17m/s for 10 hpa and 30 hPa respectively. Currently the mean zonal winds at those levels are well behind that, but forecasts suggest that they will be there or thereabouts by the end of the month. http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=all&forecast=f240&lng=eng I think that come the end of November they will be above the climatology mean.
  24. chionomaniac
    And exactly what relevence does this have to the upcoming winter, Smithy? Please post in an the appropriate thread - model moods would be best for this post.
  25. chionomaniac
    Long term if this research proves to be valid, it looks like great news to be able to predict the AO in Oct - obviously we will need to see how the research hold up when any paper is released.
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