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snowking

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snowking last won the day on November 5 2014

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    greenwich, se london 0m asl & elsenham, nw essex 97m asl

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  1. Hopefully the last 24 have shown that when we have limited resolution modelling trying to cope with the physics of an unusual stratosphere setup (ie against climatology) then nothing is certain - anybody thinking off the back of the 12z GFS suite that we’re back in the game should go back and read the last 24 hours of posts and see how quickly things can change back and change again fascinating watching, but far from certain on any model suite right now
  2. There was some discussion about this on Twitter when this article was published - essentially, NWS forecasters themselves came forward and said there was no truth to this as far as they knew https://twitter.com/everythingwx/status/1083039436257017857?s=21 And then came this from the deputy administrator of NOAA https://www.postandcourier.com/opinion/commentary/weather-prediction-still-accurate-even-during-shutdown/article_6944faba-15d3-11e9-96ea-b79ddbf38e0b.html So I think any thoughts that the government shutdown has affected GFS performance are as unfounded as the whole ‘lack of data’ fallacy we get over Christmas every year
  3. I see @Catacol has made a similar point above but for the benefit of everyone as a reminder - Crewe, you’re hardly the first person to do this this season and is suspect you will be far from the last, but those meteociel strat charts only show temperature at 10mb - and temperature is not the indicator of where the vortex is/isn’t, you need to look at GPH for that. So, here’s where we were on the 12th: In fairness, the stratospheric high not too far from the north of Scandinavia, but certainly not a ‘direct imprint’ indicative of Scandinavian blocking. This does not, of course, mean that we won’t see a Scandinavian high in the tropospheric pattern, as we don’t always get a direct vertical downwell of the stratosphere into the troposphere, but drawing this conclusion based upon the stratospheric pattern on the 12th is I’m afraid not quite right.
  4. Two things - 1. BBC website location forecasts (not that anybody should be paying any attention to these) are derived from the ECMWF now - presumably raw det. 2. @bluearmy that’s twice now you’ve mentioned west based negative NAO in the last 18 hours...what are you trying to do to me?! Still a very prominent risk I think given the location of troughing anomalies on seasonal modelling suites, and looking at the last couple of EC46 runs....but to put on my rose tinted aviators for a second, fortunately that risk looks to be out at week 5/6, and we still have weeks 2, 3 and 4 to get through before then - even then, it’s not impossible to get cold and snow with a west based -NAO, it just depends how much cold we could inject into any residual troughing before then Anyway, all speculation on far away modelling for now
  5. Therein remains my only concern - we have seen on a number of occasions in recent years modelling tendency to remove heights from the Greenland locale too readily Now in all fairness, both seasonal and now weekly modelling have been fairly consistent in lower heights there until beyond mid Jan, followed by their swift removal, which we have seen happen in a number of the more memorable winter spells...but there’s still just that little voice at the back of my mind (I like to think of it as a miniature @nick sussex) telling me not to buy into it until we’re within at least 7 days. I was also interested in your views @bluearmy on weeks 5/6 on the weeklies I saw you mention - from the brief glimpse I’ve caught of week 5 and 6 from Twitter, it looked like the risk of an increasingly west based negative NAO as time went on with the core of Greenland H500 heights sucked westwards - but you get to see far more of the suite than me, so hopefully that view is incorrect?
  6. Does anyone have a link to these? (Thanks in advanc!) In any case, the first glances at the latest EC46 look consistent with the previous update. It’s a shame we couldn’t see a quicker trop response, but the slower one certainly looks pretty promising
  7. I have to confess I have been pretty underwhelmed with the tropospheric downwelling modelled by the ECM op so far, this from yesterday’s 12z at day 10: I guess that’s what’s to be expected from an attack on the vortex during a VI period (and probably with a wQBO). That said, it’s still a significant slowing down of the zonal winds throughout the vertical profile and will create opportunities for northern blocking as we head into January. It looks rather like, for now, we’ll need to rely on a coupling of the stratospheric and tropical forcings - which continue to look pretty favourable the further we head into Jan with a like phase 8/1 MJO.....some of that should encourage further pressure on the vortex too and whilst AAM continues to ping backwards and forwards as it has done in recent months, further mountain torquing should create additional further pressure through January. It’s far better to have continued attacks on a weak vortex than a raging one
  8. Admittedly this is at 30mb, but a proper view of the FV3 stratosphere: A complete split evident there with a minor geopotential wave coming in through the Atlantic sector to aid the Wave 1 displacement from the Pacific Whilst you could argue that one of the daughter vortices being that close to Greenland is not ideal (were that pattern to impress itself on the troposphere too), assuming any ridging followed suit, then you're getting into high risk high reward scenarios with some blocking likely around the GIN corridor somewhere and a likely southerly-displaced but still potentially active jet stream roaring just underneath it if everything falls into place....a la 2013 Still, this is only a single run from an experimental output which has had lower anomaly correlation out at day 10 than the model it is supposed to replace....I would recommend for now sticking with the EPS guidance as I suspect this will (eventually....not yet while everything is still chaotic) give us the first glimpse of what effect the impending stratospheric shenanigans will have on the troposphere through the second 2/3rds of January
  9. I don’t have the time for a full reply right now - and we should still be cautious of any model output at such a range without some ensemble consensus (which fortunately we do have to a large extent at the moment). But the primary reason that stratospheric modelling should in theory be more accurate is that it is an easier environment to model - you don’t have large geographic features like bodies of water and big mountains in the way, you’re essentially dealing with a flat “surface”. Of course, there is always the argument that as tropospheric behaviour can affect the stratosphere, it is still open to the same flaws, but generally the physics of the situation should be easier to handle
  10. Ditto the EC46 really I commented the other day about the GLOSEA anomaly potentially being a little far north with the low heights for comfort - it’s one of two things for me. Either, it will be a relaxation/delaxation (no idea if that is an acceptable word but I stand by it) of a more west based -NAO.....or its the perfect recipe for some very big snow events with the perfect mix between just enough polar sourced air and Atlantic moisture January is going to be a really properly fascinating month on so many levels (that is an intentional stratospheric pun....I make no apologies...)
  11. The other encouraging thing in recent runs of the FV3 has been the tendency towards another warming phase through Western Siberia towards the end of the run - yet another shot at the vortex. We have below the peak of the first wave of warming Then this secondary bout of warming (also visible on the 0z):
  12. Some timely tweets from Ventrice - how is this for a 51-member ensemble MEAN warming - temperatures in the -15 to -10 range out at day 15 as an average. The reality could be much much warmer EDIT: Just adding the anomaly view in, in case anyone missed just how significant a projected warming this really is
  13. If I'm going to be purposely picky and a little bit obnoxious towards the models.....the only thing I would comment on is that the low MSLP anomaly is a little further North than one would like in an absolutely perfect world. Some would argue that this throws plenty of opportunity for precipitation into the mix....others would argue that it has just the faintest of tinges of the risk of a more west-based -NAO pattern to it.... But I caveat all of the above with the fact that this is a three month average anomaly, and with that sort of pattern, should it prove to be correct, there will be more than enough opportunity for the UK to join in the fun - and this is actually more in line with my thoughts for the coming months than the ECM seasonal projection in terms of where the core of the higher anomalies may sit
  14. 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.
  15. It’s a difficult one to ask for really, for people to be patient whilst the current tropospheric pattern, frustratingly close to cold as it is, delivers not much to the UK but does put on its steel toe-capped boots and gives the stratospheric vortex some Vinnie Jones tackle treatment - of course this doesn’t guarantee cold for the UK, but I’m of very similar mind to you in terms of where the gaps are likely to be left in the vortex in the longer term If anyone needs a reminder of why this is - think December 2012....then think January (and March) 2013. This sort of tropospheric pattern puts us right in the mix in the longer term. Hang on in there
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