Jump to content

Bring Back1962-63

Members
  • Content count

    176
  • Joined

  • Last visited

  • Days Won

    14

Bring Back1962-63 last won the day on December 24 2017

Bring Back1962-63 had the most liked content!

Community Reputation

4,271 Exceptional

4 Followers

About Bring Back1962-63

  • Rank
    Bring Back 1962-63

Profile Information

  • Gender
    Male
  • Location
    Exmouth 65m (212ft) asl
  • Interests
    Everything weather related; glaciation; coin collecting; cricket; bridge
  • Weather Preferences
    Extremes - especially cold and snow

Recent Profile Visitors

4,634 profile views
  1. That's a great first post on here @Tamara and thank you so much for your efforts. I'm sure that it'll provoke many questions. I know that you have other commitments and will not always be able to respond quickly but your answers will always be worth waiting for! Just had a glance at the "GSDM" link that you provide and you're right, that's a great source and wealth of information that I'll keep returning to. It's a bit like a text book one is given at the beginning of the new year as a student and needs to be read in conjunction with all the learning on this thread. I promise to do all my homework, miss! I'm in the middle of preparing my next post for this thread which should be ready tomorrow morning. So, I'll save any questions that I have for you until after that. I look forward to your future contributions on here and perhaps we shall get a good thread discussion going before too long. Thank you again, David
  2. Hello Malcolm, welcome to our friendly thread. What a great first post on here and thank you for making such an effort. You've obviously given yourself some homework and spent a good deal of time reading up on this part of the subject to prepare this contribution. I'm fairly sure that you'll see several of the specialists dealing with this when they have time to do justice to it (not sure how quickly that will be - like everyone else they have busy lives). From my still limited (and basic) understanding of angular momentum, it's a pretty complex science and will need to be broken down into the sequence of events (what causes what) but once one masters those basics, things really start to make a lot of sense. Anyway, I will not interfere any further until they've had a chance to respond,.I have plenty of questions to ask about many aspects of this fascinating subject myself and I'll come in with those in a few days time. I'll be posting myself later in the week. All the best, David
  3. GENERAL UPDATE: Welcome to everyone to whom I haven't done so already. I am delighted to see that this thread is starting to gather pace. The examples of the exchanges above on "magnetism" are precisely what part of this thread is all about. Everyone is encouraged to provide links to papers and to try to help out with anyone else's queries, Then if one (or more) of these papers is known by any of us (like Knocker posted above) to be controversial or out of sync with current thinking, then it's important to give a steer on this. This does NOT mean that anyone should stop posting any links or papers etc as this is the thread to dissect them. I feel that many of us will be interested in this part of the subject to see where it fits in with the other teleconnections. I have a friend who I know has taken an interest in the earth's magnetism and solar influences and how they impact on both volcanism and the atmosphere. I haven't been in touch with her for a while but I've just sent her an email to invite her to join the NetWeather Forum and to contribute on this thread. So I hope that she responds and joins - I'll let you know whether this happens. I briefly looked for a few papers on this subject last night. I did a Google search and would you believe that the first item listed (last night anyway) was this thread! Probably because I mentioned magnetism amongst the teleconnections in my introductory post. This was the link then: https://www.google.co.uk/search?ei=x09ZWte4AZCykwXt6IXACw&q=teleconnection+earth's+magnetism&oq=teleconnection+earth's+magnetism&gs_l=psy-ab.12...15810.24881.0.27188.19.19.0.0.0.0.81.1384.19.19.0....0...1c.1.64.psy-ab..0.0.0....0.tNvN8rObQv8 My first reaction was, gosh the power of the internet - what have I started here?. On reflection, I hope that with this "wider exposure" we might attract a few more people with these shared interests, including a few specialists, from outside the NetWeather Forum and worldwide. Anyway, still very early days but with all your help we have a wonderful opportunity to make this thread into something very special and very useful. I know that there will be a few more excellent posts coming from some of those who will be amongst "our regulars" and these will be a mix with a focus on either "technical" or "learning". I should just mention (if I haven't already), that I run a full time online business (coin dealing) from home and that occupies me for lengthy periods. In fact, my busy periods are from Saturdays to Wednesdays and " my weekend" consists of Thursdays and Fridays! That is when I prepare my longer posts and it will also be the time when I can get much more involved on here. During the rest of the week, I will look in as often as I can. I had to deal with an unsavoury post this morning which I (and I believe) several of you also reported. The mods removed it very quickly. I will not mention any names publicly but there is a minority of forum members who simply dismiss almost anything to do with teleconnection science. If they can argue their case respectfully with evidence then fine, we can debate it here in a friendly way. This is not the MOD thread and one of the reasons why I created this thread was.to get away from that group of people and attract members with at least "an open mind". Then we can all learn much more and some of the rather more "sceptical" amongst us might develop a rather different view in the course time. If anyone has any particular issues, please feel free to PM me and I will endeavour to respond as soon as I can - I'm usually not far away from my computer! Finally, thank you to those who have got involved so far and please keep looking in, contributing and spreading the word.
  4. FONT SIZE ISSUES - A GOOD OLD BRITISH COMPROMISE I have noted the various mixed views and comments regarding font size.This is from both the MOD thread as well as this new "Learning All About Teleconnections" thread that I launched last night. I will try to remember to reduce my font size just before I press the "submit" button. I had no idea that I would cause such a "mixed" reaction and I apologise to everyone (including the moderators) for seemingly disrupting the MOD thread at a busy time which would never be my intention. I pride myself on the use of good English and presentation skills and this matter really concerns me. There is something of a dilemma which I want to post here as it's extremely relevant to many who post anywhere on this forum. I am deliberately ensuring that @Paul will read this and I will also be sending him a PM about a particular aspect of it shortly. I will also see if he or someone in his team can edit my last 5 posts (one on page 27 of the MOD thread and 4 on the new thread) to reduce the font size to what I outline below. In particular, I really struggled with the text in my 3rd post on this thread. The one where I quote (or copy) part of Snowy Hibbo's and Tamara's posts. Each original post was not only in a different font size but in different font faces (or styles). There seems no feature on NetWeather to change the style. So, I thought that I'd overcome this problem by copying everything to a word document on my computer and change it all to "Times Roman" my preferred style. When I copied it back to the pre-submit mode (as well as the editor facility) to my horror it changed back to its original 3 style format! It drove me half crazy trying to fiddle around with it especially after writing 4 long posts yesterday. I think that 3rd post looks hideous and it's intended as a "demonstration" post for this thread, I'm not happy with it!. Part of the problem is that some of the posters (like me) work from our trusted desktop PCs and some use their laptops. I now understand that many use mobile apps, perhaps even a majority these days and the viewing is very different. It is not just a generation thing as my brother dispensed with his desktop several years ago and, unlike me, he is far more in touch with the outside world! I asked him this morning to give me a demonstration of the problem. I was quite shocked just how little of the text shows up even when he did that finger movement thing to varying the size on the tiny screen. I can also see how difficult it is to use the mobile app for posting oneself and I can see why we have an abundance of short posts and some "part view" charts and with a vertical view when they appear on here. This is one side of the coin but please read on. Although my general eye sight is very good, I have been wearing reading glasses for the last 15 years or so and (I just had my last annual eye test and there was no deterioration - but coming up to age 65, I need to have regular checks). It is difficult for me to read very small print and anything from font size 12 and below is a real struggle. I use "varifocals" for when I'm working on my desktop computer. I write everything in a much larger font size so that I can edit it easily and correct typos and spelling errors etc. With the new 15 minute editing time restriction, I find it hard to check everything (including all the links and charts) on my long posts. I have partially overcome this by proof reading everything several times prior to submitting the post. I will try to ensure from now on that my final action prior to submitting any type of post is to reduce the font size from the 16 to 18 (or even 20 for titles) that I have been using down to size 14 for standard text and only 16 for titles and headings - just like on this post, This is effectively meeting some of you halfway and I sincerely hope that this really helps. Sometimes in this world of increasingly polarised views, a good old British compromise might still be the best way forward and I hope that most of you agree. Finally, I just remembered to reduce this from font size 18 to size 14! David
  5. FONT SIZE ISSUES - A GOOD OLD BRITISH COMPROMISE I have noted the various mixed views and comments regarding font size.This is from both the MOD thread as well as the new "Learning All About Teleconnections" thread that I launched last night. I will try to remember to reduce my font size just before I press the "submit" button. I had no idea that I would cause such a "mixed" reaction and I apologise to everyone (including the moderators) for seemingly disrupting the thread at a busy time which would never be my intention. I pride myself on the use of good English and presentation skills and this matter really concerns me. There is something of a dilemma which I want to post here as it's extremely relevant to many who post anywhere on this forum. I am deliberately ensuring that @Paul will read this and I will also be sending him a PM about a particular aspect of it shortly. I will also see if he or someone in his team can edit my last 5 posts (one on page 27 of the MOD thread and 4 on the new thread) to reduce the font size to what I outline below. Part of the problem is that some of the posters (like me) work from our trusted desktop PCs and some use their laptops. I now understand that many use mobile apps, perhaps even a majority these days and the viewing is very different. It is not just a generation thing as my brother dispensed with his desktop several years ago and, unlike me, he is far more in touch with the outside world! I asked him this morning to give me a demonstration of the problem. I was quite shocked just how little of the text shows up even when he did that finger movement thing to varying the size on the tiny screen. I can also see how difficult it is to use the mobile app for posting oneself and I can see why we have an abundance of short posts and some "part view" charts and with a vertical view when they appear on here. This is one side of the coin but please read on. Although my general eye sight is very good, I have been wearing reading glasses for the last 15 years or so and (I just had my last annual eye test and there was no deterioration - but coming up to age 65, I need to have regular checks). It is difficult for me to read very small print and anything from font size 12 and below is a real struggle. I use "varifocals" for when I'm working on my desktop computer. I write everything in a much larger font size so that I can edit it easily and correct typos and spelling errors etc. With the new 15 minute editing time restriction, I find it hard to check everything (including all the links and charts) on my long posts. I have partially overcome this by proof reading everything several times prior to submitting the post. I will try to ensure from now on that my final action prior to submitting any type of post is to reduce the font size from the 16 to 18 (or even 20 for titles) that I have been using down to size 14 for standard text and only 16 for titles and headings - just like on this post, This is effectively meeting some of you halfway and I sincerely hope that this really helps. Sometimes in this world of increasingly polarised views, a good old British compromise might still be the best way forward and I hope that most of you agree. Finally, although I hope that the moderators will allow this post to remain on here (and also in the Teleconnections thread), I feel that if you have any points to make on this matter either way, that you simply PM me or send a sticky note message. I do not wish to be accused of clogging up the thread again. Oh, I just remembered to reduce this from font size 18 to size 14! Just a reminder of the new thread (just click on the chart below):
  6. Thank you Knocker and welcome to this thread. The link that you provide is just what we are looking for. I have just looked at the video and it is fascinating. I hope that it'll promote some comments and discussion from our technical contributors - way beyond my pay grade!. I note that this was published in 2014 and I'm not sure if there have been further papers on this specific aspect of the MJO. Last year, I exchanged emails with Kyle McRitchie and you probably know that he has focused on Indian Ocean and tropical forcing and devised his own MJO "ENSO adjusted" plots with mixed results (I think). Once this thread has had a chance to get up and running properly (I hope) I will invite Kyle to make the occasional "guest contribution". The same will go for other experts in relevant areas. I want to build a library into this thread and I've been discussing this with Paul. He has been working on a way of doing this which is likely to be ready next week - this is so that it can be continuously worked on and updated without the usual forum editing constraints. I will create a good cross indexing system so that any papers can easily be located under one or several headings. So, your link will be one of the first entries into our library
  7. Thank you, @Snowy Hibbo (Zac) and @Catacol (Alistair) for you excellent initial posts and welcome to our new thread. I know that I shall learn a lot from both of you and I hope that many others will too. Much too late for any questions tonight but I'll have several in the morning. The news does seem more encouraging for later this month and into February. Thank you for your comment @Nick L nice to have someone from the Forum Team on here already. I hope that you might contribute from time to time. I note your comment regarding font size (put much more respectfully than John H managed earlier (must have been a bad day for him!). I will try to remember to reduce my font size just before I press submit. I wear reading glasses and use varifocals for computer work. Just had my last eye test and no deterioration but coming up to 65 I need to have regular checks. It is difficult for me to read small print but I agree, a compromise might be a good solution. My 3rd post where I quoted 3 parts of earlier posts (from 3 members) really caused me a problem. Each original post was not only in a different font size but in different font faces (or styles). There is no feature on NetWeather to change the style. So, I thought that I'd overcome this problem by copying everything to a word document on my computer and change it all to "Times Roman" my preferred style. When I copied it back to the pre-submit mode (as well as the editor facility) it changed back to its original 3 style format! It drove me half crazy trying to fiddle around with it especially after writing 4 long posts today. I have very high standards of English and presentation and this compromises those standards. Is there any way around this problem or is it possible that NetWeather can add the font style option above all pre-submit posts? May be this is one for Paul but if I can leave it with you, I'd appreciate someone answering this. All the best, David.
  8. Thank you for your kind comments and welcome to this thread.This is exactly what we would like to encourage. Please feel free to post whenever you like and ask any questions.
  9. A FEW OF THE UNCERTAINTIES AND ISSUES IN RELATION TO MODEL OUTPUT GOING FORWARD It is a whole week since I last posted on the model thread and I ended that one by saying that I was working on an exciting new project. Well, I can now tell you about it. Earlier this evening, I opened a new specialist thread, entitled “Learning About Teleconnection Science and Background Signals”. This post will be rather shorter than my normal meanderings as I’m pretty exhausted after launching the specialist thread and it’s my 4th post of the day - I have been working on the other 3 for several days which are all on the new thread. I have already posted this one there too but with a slightly different introduction. My introductory post there explains why I did it and what’s it all about. Here is the link to the new thread: https://www.netweather.tv/forum/topic/89161-learning-about-teleconnection-science-and-background-signals/ Alternatively, you can just click on the chart below: I am very much one of the learners but I’m hoping that the specialist thread will evolve into something that is not only for learners but also to cater for the more technical aspects of the subject. It has only been running for an hour or so and it’s obviously very early days but for those interested, please take a look. I have spoken to one or two other members and I know that there will be a few posts going on there during the next few days, so the message is “please keep checking in”. Right, back to this post. Although I am a passionate coldie and love the white fluffy stuff like the majority of members on this weather forum, I have been endeavouring to manage my expectations in recent weeks. I have been learning a little more about some of the processes that are largely responsible for what delivers the broader weather patterns to us. This is the background signals and the teleconnections. I still have an awful lot to learn but from what I now understand, I will now attempt to provide my take on what is likely to drive the model output going forward through January and into February. Much of this winter so far has been a case of “almost but not quite”. We started with many brief northerlies almost once a week but these were always quickly replaced by less cold conditions. Several of these Arctic outbreaks were slightly more potent and many (but by no means all) parts of the country saw some significant snowfall. Even these cold spells did not last long. A typical La Nina winter is often front-loaded, starting off with frequent HLB and we did indeed, more or less, see some of that. Then this would normally give way to the seasonal strengthening of the PV and the jet stream with flatter patterns and generally much more unsettled and milder conditions but with brief colder interludes also possible through mid-winter. Well, it hasn’t really been a typical La Nina. It hasn’t been the strongest of them but it has often still had enough oomph to make an impact. The more unusual aspect was that it has been largely east Pacific based with the colder currents upwelling there but with less cold currents further west. In fact with the generally well above average SSTs over the tropics and much of the rest of the oceans (especially in the Arctic), the surface currents in the central and west Pacific have really been “less warm” than recently rather than colder than average. This east position can produce a rather different outcome to that associated with a more normal La Nina. Much would depend on the extent of “angular momentum” (AAM) and how this impacts on the GWO (global wind oscillation) phases. It is this part where I’m still learning some of the basics from several of our teleconnection specialists. I’m confident that they will explain if, where and how I have gone wrong (that’s where the “learning area” in the specialist thread should prove its worth). From what I understand (and this is really in far too simplistic terms), we saw an uptick in AAM in late December – hence the “initial” suggestion (with all the usual caveats) that we would see a build of heights to our north-east. A positive AAM tendency with its tropical convection forcing creates waves or ripples that generate frictional torque (stretching of the atmosphere with any movement one way having to be corrected the other way to cancel out what would otherwise be a vacuum which is unsustainable). These waves then ripple out and start to generate ridges and troughs in the atmosphere. These are most prominent initially in the Pacific. Then this ridging has knock on effects downstream setting up further ridges and troughs. As this movement impacts on mountainous areas like the Rockies it creates further stretching known as “mountain torque”. It is this that can strongly impact on the jet stream, causing it to take on different trajectories and to buckle and meander. With higher AAM, this often eventually favours ridging in the central Atlantic and this can also favour greater HLB. The GWO is an indicator of how the AAM tendency is likely to impact. I believe that phase 4 is the best position for the most favourable blocked patterns, whereas phase 2 is usually associated with little or no HLB but with rather more MLB possible (last winter was quite an extreme example of this). This can allow very modest and only temporary amplification. Shortly before Christmas, the AAM tendency nose-dived and that was why some of our teleconnection specialists started to say the easterly would barely materialise. The blocking simply would not be sustainable and would, in due course, be pushed away eastwards. The models eventually locked on to this background signal. Then, there were some better signs going forward. It seemed that the AAM would recover and the GWO would enter phase 4 down the line. Hence some rather more optimistic tones from the likes of GP. Unfortunately, the AAM has remained stubbornly low and, I believe, the latest forecasts do not indicate an early change to this. So, the GWO may well remain in phase 2 for a while. That would be back to a rather flatter pattern. It does not mean that all is lost. We would need a “bounce” in AAM tendency but we may have to wait until the east Pacific La Nina weakens a little more. I haven’t mentioned the MJO but that too is largely influenced by the primary drivers. The MJO can assist and compliment the AAM when it’s in the right phases. There has been some discrepancies over the MJO output in recent weeks. The GFS currently show it at decent amplitude in phase 5. The problem is that a negative AAM is likely to cause the MJO to die a death again as it reaches the key phases of 7, 8 and 1. That would be into early February anyway, so there is still just about time for a sudden bounce in AAM but , as I said this may not be very soon (if at all). Then if we get an SSW (sudden stratospheric warming) and this does propagate down to the surface, it seems that we still need the AAM to play ball with the tropospheric profile in order to assist with HLB to release the cold from the Arctic (and in the correct alignment to deliver that cold to western Europe and the UK). I have learnt about some of this in very recent weeks and I can assure all of the coldies that I do not wish to deliver any bad news. I may still be a novice regards to the AAM/GWO etc and I’m still learning but I do believe that I’m broadly correct in what I've just said. Having got all the potentially bad news out of the way, things could actually be a lot worse. This winter has had a habit of managing quite a few colder interludes and several snowfalls. In fact every time the models have switched their mid-term output to a more zonal, unsettled and milder pattern, when we get to zero in on that pattern change it has mostly turned out to be only a brief period of milder and unsettled weather. So this is how we coldies should deal with this. Accept that the specialists will indicate to us as soon as they see any improvements to the longer term picture (and I will post on that very quickly if or when that happens). Meanwhile, most of the rest of us can focus on the short to medium term, which is what the model thread is all about – dissecting the more “reliable” period. There definitely seems to be some rather better news to report here, although there are considerable uncertainties as well. Firstly, I want to have a close look at the jet stream. To give an idea of the variety of outcomes, I’ll do what I did once before Christmas, have a look at the latest GEFS panels from the 12z output: T+6 T+120 T+180 T+240 T+360 The panels only show the Atlantic and Europe view, so I start off with the current GFS Northern hemisphere view. We're just on the cold side of the meandering jet with the loop passing north to south. By T+120 (day 5), the panels are pretty consistent in showing a much stronger jet heading more or less from west to east either straight towards the UK or very slightly further south. This would confirm the generally west-north-westerly pattern at that stage with some Polar Maritime air in the mix. By T+180 (day 7/8) most of the ensemble members now show the jet taking on a much more north of west tilt with almost all of the members between west-north-west/east/south-east or a more direct north-west/south-east trajectory. Most of the members show the jet slightly further south but generally still moving through the UK. This confirms that there will be considerably more Polar Maritime air in the mix. By T+240 (day 10), the trajectory has generally changed to more of a north to south trajectory. The jet has weakened to at least some extent but far more so with a few members. It is either passing straight through us or just to the west of us. This will generally put us under an Arctic air stream and hence the northerly. We can have a sneak preview of the unreliable period of T+360 (day 15). All of a sudden we see a huge range of outcomes which really proves that we should not look beyond day 10. The majority still show some sort of rather cold to colder pattern but some have us on the warm side of the jet and there is a wide range of strengths too. Remember, by this time we would need some changes feeding through from the AAM/GWO to have a chance of any more sustainable cold (but this would be too early any). So the best we can probably hope for are a few days of cold northerlies with some good snow chances for at least some of us. Yet again, we would be making the best out of what could have been a pretty dire pattern for coldies - in fact little evidence of anything mild around the corner (other than perhaps for one or two days prior to the northerly). If you wish to view any of the panel charts more closely, you can do this by using the links below and then just click on any of the charts to enlarge them: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=120 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=180 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=240 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=360 I've had a good look at the jet stream profiles on the other models and there is reasonable agreement right up to day 10. Several models show the jet pushing slightly further south. I just want to have a very quick look at northern hemisphere temperatures. I do not have time for one of my Arctic or EurAsia temperature and snow cover analyses but I will update these next week ahead of the anticipated northerly snap. I will not do a cross-model analyses at this stage either. In my last report (on page 112 of the Dec 30th model thread) I pointed out that the current severe cold in North America would ease considerably going into next week with much of the cold at last transferring back to the Asian continent with some getting closer to Europe. So firstly several 850 charts again from the 12z output: 850 Temperatures: GFS T+6 GFS T+120 GFS T+240 The GFS does continue to transfer the cold across to Asia and Russia. By day 10 there are some much lower 850s in northern Asia, Russia and Siberia and rather lower temps in Scandinavia too. The 850s over us do look rather marginal suggesting it might be mostly snow over higher ground during the northerly unless we manage another slider or transitional snow when less cold air moves in later on. 850 Temperatures: ECM T+0 ECM T+120 ECM T+240 The ECM charts are not programmed to register below -28c (while GFS go down as far as -40c). If anything, ECM transfer even more of the cold to Asia but also rather more into Europe by day 10 and also slightly less marginal 850s across the UK. I'm certain that many posters will follow these developments very closely as the northerly gets into the day 5 range. 2M Surface Temperatures: GFS T+6 GFS T+120 GFS T+240 Much the same transfer applies to the surface cold. The GFS shows that North America takes a little longer to give up some of the deeper cold but by day 10 the USA is considerably warmer. Meanwhile Northern Asia, Siberia and much of Russia have developed their deepest cold of the winter with an extensive area of sub -28s to sub -40s. By day 10, Scandinavia is very cold and most of Europe is close to freezing and the UK is under 0c to +4c temperatures. Remember, these charts are for 1300, so very close to the maximums (everything else remaining equal). We must give credit where it is due. I pointed out a week ago that the GFS was showing this cold transition in its FI charts and now it has moved into the more reliable period. So, they seem to have at least nailed this change and quite well ahead of the other models, which are now all following suit. Let's just confirm that with several other models' charts. 2M Surface Temperatures: GEFS mean T+240 GEM T+240 NAVGEM T+180 I've only used the Meteoceil Northern Hemisphere charts and several models, like the ECM, are not shown there. The GEFS mean is interesting at T+240 as it shows similar deep cold to the GFS operational run. This is the average of all 20 ensemble members, plus the control and op runs. Very few members show less extensive cold on the Asian continent but there are some that show more of the cold extending into Europe. GEM is similar and NAVGEM (only out to T+180) is well on the way. So, I'm delighted to close with some better news. If only someone can give that AAM a big nudge to get it spiking upwards then we might just manage some synoptic patterns to help deliver that cold to our shores. If anyone wants to discuss any aspect of this post, particularly the first part, then you'll be very welcome on the new teleconnections thread.
  10. A FEW OF THE UNCERTAINTIES AND ISSUES IN RELATION TO MODEL OUTPUT GOING FORWARD Although I am a passionate coldie and love the white fluffy stuff like the majority of members on this weather forum, I have been endeavouring to manage my expectations in recent weeks. I have been learning a little more about some of the processes that are largely responsible for what delivers the broader weather patterns to us. This is the background signals and the teleconnections. I still have an awful lot to learn but from what I now understand, I will now attempt to provide my take on what is likely to drive the model output going forward through January and into February. This post will be rather shorter than my normal meanderings as I’m pretty exhausted after launching this specialist thread and it’s my 4th post of the day (although I have been working on the other 3 for several days). I shall also post this one on the model thread shortly but with a slightly different introduction and I will also be advertising this thread there. Much of this winter so far has been a case of “almost but not quite”. We started with many brief northerlies almost once a week but these were always quickly replaced by less cold conditions. Several of these Arctic outbreaks were slightly more potent and many (but by no means all) parts of the country saw some significant snowfall. Even these cold spells did not last long. A typical La Nina winter is often front-loaded, starting off with frequent HLB and we did indeed, more or less, see some of that. Then this would normally give way to the seasonal strengthening of the PV and the jet stream with flatter patterns and generally much more unsettled and milder conditions but with brief colder interludes also possible through mid-winter. Well, it hasn’t really been a typical La Nina. It hasn’t been the strongest of them but it has often still had enough oomph to make an impact. The more unusual aspect was that it has been largely east Pacific based with the colder currents upwelling there but with less cold currents further west. In fact with the generally well above average SSTs over the tropics and much of the rest of the oceans (especially in the Arctic), the surface currents in the central and west Pacific have really been “less warm” than recently rather than colder than average. This east position can produce a rather different outcome to that associated with a more normal La Nina. Much would depend on the extent of “angular momentum” (AAM) and how this impacts on the GWO (global wind oscillation) phases. It is this part where I’m still learning some of the basics from several of our teleconnection specialists. I’m confident that they will explain if, where and how I have gone wrong (that’s where the “learning area” in the specialist thread should prove its worth). From what I understand (and this is really in far too simplistic terms), we saw an uptick in AAM in late December – hence the “initial” suggestion (with all the usual caveats) that we would see a build of heights to our north-east. A positive AAM tendency with its tropical convection forcing creates waves or ripples that generate frictional torque (stretching of the atmosphere with any movement one way having to be corrected the other way to cancel out what would otherwise be a vacuum which is unsustainable). These waves then ripple out and start to generate ridges and troughs in the atmosphere. These are most prominent initially in the Pacific. Then this ridging has knock on effects downstream setting up further ridges and troughs. As this movement impacts on mountainous areas like the Rockies it creates further stretching known as “mountain torque”. It is this that can strongly impact on the jet stream, causing it to take on different trajectories and to buckle and meander. With higher AAM, this often eventually favours ridging in the central Atlantic and this can also favour greater HLB. The GWO is an indicator of how the AAM tendency is likely to impact. I believe that phase 4 is the best position for the most favourable blocked patterns, whereas phase 2 is usually associated with little or no HLB but with rather more MLB possible (last winter was quite an extreme example of this). This can allow very modest and only temporary amplification. Shortly before Christmas, the AAM tendency nose-dived and that was why some of our teleconnection specialists started to say the easterly would barely materialise. The blocking simply would not be sustainable and would, in due course, be pushed away eastwards. The models eventually locked on to this background signal. Then, there were some better signs going forward. It seemed that the AAM would recover and the GWO would enter phase 4 down the line. Hence some rather more optimistic tones from the likes of GP. Unfortunately, the AAM has remained stubbornly low and, I believe, the latest forecasts do not indicate an early change to this. So, the GWO may well remain in phase 2 for a while. That would be back to a rather flatter pattern. It does not mean that all is lost. We would need a “bounce” in AAM tendency but we may have to wait until the east Pacific La Nina weakens a little more. I haven’t mentioned the MJO but that too is largely influenced by the primary drivers. The MJO can assist and compliment the AAM when it’s in the right phases. There has been some discrepancies over the MJO output in recent weeks. The GFS currently show it at decent amplitude in phase 5. The problem is that a negative AAM is likely to cause the MJO to die a death again as it reaches the key phases of 7, 8 and 1. That would be into early February anyway, so there is still just about time for a sudden bounce in AAM but , as I said this may not be very soon (if at all). Then if we get an SSW (sudden stratospheric warming) and this does propagate down to the surface, it seems that we still need the AAM to play ball with the tropospheric profile in order to assist with HLB to release the cold from the Arctic (and in the correct alignment to deliver that cold to western Europe and the UK). I have learnt about some of this in very recent weeks and I can assure all of the coldies that I do not wish to deliver any bad news. I may still be a novice regards to the AAM/GWO etc and I’m still learning but I do believe that I’m broadly correct in what I've just said. Having got all the potentially bad news out of the way, things could actually be a lot worse. This winter has had a habit of managing quite a few colder interludes and several snowfalls. In fact every time the models have switched their mid-term output to a more zonal, unsettled and milder pattern, when we get to zero in on that pattern change it has mostly turned out to be only a brief period of milder and unsettled weather. So this is how we coldies should deal with this. Accept that the specialists will indicate to us as soon as they see any improvements to the longer term picture (and I will post on that very quickly if or when that happens). Meanwhile, most of the rest of us can focus on the short to medium term, which is what the model thread is all about – dissecting the more “reliable” period. There definitely seems to be some rather better news to report here, although there are considerable uncertainties as well. Firstly, I want to have a close look at the jet stream. To give an idea of the variety of outcomes, I’ll do what I did once before Christmas, have a look at the latest GEFS panels from the 12z output: T+6 T+120 T+180 T+240 T+360 The panels only show the Atlantic and Europe view, so I start off with the current GFS Northern hemisphere view. We're just on the cold side of the meandering jet with the loop passing north to south. By T+120 (day 5), the panels are pretty consistent in showing a much stronger jet heading more or less from west to east either straight towards the UK or very slightly further south. This would confirm the generally west-north-westerly pattern at that stage with some Polar Maritime air in the mix. By T+180 (day 7/8) most of the ensemble members now show the jet taking on a much more north of west tilt with almost all of the members between west-north-west/east/south-east or a more direct north-west/south-east trajectory. Most of the members show the jet slightly further south but generally still moving through the UK. This confirms that there will be considerably more Polar Maritime air in the mix. By T+240 (day 10), the trajectory has generally changed to more of a north to south trajectory. The jet has weakened to at least some extent but far more so with a few members. It is either passing straight through us or just to the west of us. This will generally put us under an Arctic air stream and hence the northerly. We can have a sneak preview of the unreliable period of T+360 (day 15). All of a sudden we see a huge range of outcomes which really proves that we should not look beyond day 10. The majority still show some sort of rather cold to colder pattern but some have us on the warm side of the jet and there is a wide range of strengths too. Remember, by this time we would need some changes feeding through from the AAM/GWO to have a chance of any more sustainable cold (but this would be too early any). So the best we can probably hope for are a few days of cold northerlies with some good snow chances for at least some of us. Yet again, we would be making the best out of what could have been a pretty dire pattern for coldies - in fact little evidence of anything mild around the corner (other than perhaps for one or two days prior to the northerly). If you wish to view any of the panel charts more closely, you can do this by using the links below and then just click on any of the charts to enlarge them: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=120 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=180 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=240 http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=360 I've had a good look at the jet stream profiles on the other models and there is reasonable agreement right up to day 10. Several models show the jet pushing slightly further south. I just want to have a very quick look at northern hemisphere temperatures. I do not have time for one of my Arctic or EurAsia temperature and snow cover analyses but I will update these next week ahead of the anticipated northerly snap. I will not do a cross-model analyses at this stage either. In my last report (on page 112 of the Dec 30th model thread) I pointed out that the current severe cold in North America would ease considerably going into next week with much of the cold at last transferring back to the Asian continent with some getting closer to Europe. So firstly several 850 charts again from the 12z output: 850 Temperatures: GFS T+6 GFS T+120 GFS T+240 The GFS does continue to transfer the cold across to Asia and Russia. By day 10 there are some much lower 850s in northern Asia, Russia and Siberia and rather lower temps in Scandinavia too. The 850s over us do look rather marginal suggesting it might be mostly snow over higher ground during the northerly unless we manage another slider or transitional snow when less cold air moves in later on. 850 Temperatures: ECM T+0 ECM T+120 ECM T+240 The ECM charts are not programmed to register below -28c (while GFS go down as far as -40c). If anything, ECM transfer even more of the cold to Asia but also rather more into Europe by day 10 and also slightly less marginal 850s across the UK. I'm certain that many posters will follow these developments very closely as the northerly gets into the day 5 range. 2M Surface Temperatures: GFS T+6 GFS T+120 GFS T+240 Much the same transfer applies to the surface cold. The GFS shows that North America takes a little longer to give up some of the deeper cold but by day 10 the USA is considerably warmer. Meanwhile Northern Asia, Siberia and much of Russia have developed their deepest cold of the winter with an extensive area of sub -28s to sub -40s. By day 10, Scandinavia is very cold and most of Europe is close to freezing and the UK is under 0c to +4c temperatures. Remember, these charts are for 1300, so very close to the maximums (everything else remaining equal). We must give credit where it is due. I pointed out a week ago that the GFS was showing this cold transition in its FI charts and now it has moved into the more reliable period. So, they seem to have at least nailed this change and quite well ahead of the other models, which are now all following suit. Let's just confirm that with several other models' charts. 2M Surface Temperatures: GEFS mean T+240 GEM T+240 NAVGEM T+180 I've only used the Meteoceil Northern Hemisphere charts and several models, like the ECM, are not shown there. The GEFS mean is interesting at T+240 as it shows similar deep cold to the GFS operational run. This is the average of all 20 ensemble members, plus the control and op runs. Very few members show less extensive cold on the Asian continent but there are some that show more of the cold extending into Europe. GEM is similar and NAVGEM (only out to T+180) is well on the way. So, I'm delighted to close with some better news. If only someone can give that AAM a big nudge to get it spiking upwards that we might just manage some synoptic patterns to help deliver that cold to our shores. If anyone wants to discuss any aspect of this post, particularly the first part, then you'll be very welcome on the new teleconnections thread.
  11. HERE’S AN EXAMPLE OF HOW SOME FRIENDLY INTERACTION CAN REALLY HELP LEARNERS LIKE ME Last week (on January 4th), I produced my most recent long post on the model thread. This was on the “December 30th 2017” thread - one that was closed yesterday by Paul. The post appears on page 122 of that thread and if you wish to refer to it, here’s the link to that page: https://www.netweather.tv/forum/topic/89088-model-output-discussion-into-2018/?page=112 I’ll just copy the introduction to that post and the key paragraphs (that I want to use to make my point) below: "WHERE DO WE GO FROM HERE? In this post, I want to very briefly review the short to medium term period and then I will look slightly further ahead. I am very busy, so I will not have time for one of my thorough cross-model analyses and anyway, there has been a far larger number of posts than usual examining the model output (can’t think why!). I will take another look at northern hemisphere temperatures again (some much better news here for us going forward). It’s a month since I last updated my Arctic ice and temperature indicators, so I’ll do this now and we have the very latest monthly Arctic report released yesterday (more very bad news here). Despite all this, I will be painting a much more optimistic picture for later this month. LOOKING SLIGHTLY FURTHER AHEAD: How the unusual (and recently changing) La Nina pattern interacts with the AAM (etc.) is also very important. The east Pacific based La Nina with the cold current upwellings there and the now almost average ocean temperatures in the central and western Pacific have created a profile which is unlikely to follow the normal Nina winter behaviour and impacts. No more detail but just to say that the current set up is much more likely to have favourable impacts compared to the usual Nina ENSO state. Then we have the recent NOAA reports that have suggested a much more lively MJO as it moves out of the “circle of death” and progresses through phases 2 and 3 at a steadily increasing amplitude. Given the timing of the 30 to 45 day full cycle, we should reach the important stages of 7, 8 and 1 later this month. Providing the MJO doesn’t die again, then that should substantially assist with establishing HLB patterns. Ideally (for coldies), we would like to see the MJO remain in those key phases for as long as possible at decent amplitude. Then we have the thoroughly disrupted tropospheric PV. There has been a huge battle for the seasonal peaks in the strength of the PV and the Jet Stream against the disruption and frequent injections of WAA into the Arctic. We have seen regular ridging of high pressure into the Pole but not sufficiently (yet) to produce much more widespread HP up there." As I always say, I still have a lot to learn about angular momentum, the GWO (global wind oscillation) and how they influence the MJO, amongst other things. I was delighted when @Snowy Hibbo responded to my post a few hours later. The MOD thread was extremely busy and you can find his post on page 128, here’s the link: https://www.netweather.tv/forum/topic/89088-model-output-discussion-into-2018/?page=128 I copy his post below: On 1/4/2018 at 16:32, Bring Back1962-63 said: Given the timing of the 30 to 45 day full cycle, we should reach the important stages of 7, 8 and 1 later this month. Providing the MJO doesn’t die again, then that should substantially assist with establishing HLB patterns. Ideally (for coldies), we would like to see the MJO remain in those key phases for as long as possible at decent amplitude .-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- I am not too sure, if a Phase 8/1 MJO signal is possible. You might notice that the last two MJO cycles have shown a significant weakening around Phase 8. That is because of the underlying Niña state. The Niña Easterlies will compete with the MJO westerlies. The Niño regions are within Phase 7/8, so that is where the strongest Niña Easterlies are. The MJO signal will be beaten by the Niña Easterlies, which is shown in the data. So a prolonged Phase 7/8/1 event is probably not going to happen IMO anyway. But this has an effect on the AAM. And after some helpful PMs and subsequent reading of studies and other online material, I have come up with this forecast. Currently we have a -MT and -FT phase. When the MJO (Westerlies) comes into interaction with the Niña Easterlies, it will cause positive frictional torque. +FT moves the GWO to Phase 3/4. The torque propragtes into the mid latitudes, and helps a +MT pattern to develop. This causes a proper GWO Phase 4, at the height of the MJO Phase 6/7. When the MJO signal weakens at the hands of Niña, the +FT will be lost, and the GWO will start to move towards Phases 8/1. Then the MT will go negative a few days after, and then the GWO Phase 1 takes hold. The MJO is linked to the AAM in this instance. Monthly models such as the EC Monthly and POAMA, show the MJO moving towards Phases 6/7 later this month, so this will be when these events occur. In the meantime, the negative AAM tendency will continue, and maybe the AAM will follow GEFS for once. Just think about that! Anyway.... the MJO moves through IO, and towards Maritime Continent. You guys in England get single digit temperatures and even freezing temperatures, and we get 41 degrees here in Melbourne. Perhaps" I was so grateful for this explanation and then @Tamara almost immediately responded and thoroughly endorsed what Snowy Hibbo had said. Her post appears on page 129, here’s the link: https://www.netweather.tv/forum/topic/89088-model-output-discussion-into-2018/?page=129 I copy her comments (without the quoted post in it) below: "Based on the quite long learning curve I have had, and experience with the GWO thus far, I must say this is one of the best overlay illustrations anyone starting out themselves so soon with the concept of the GSDM (Global Synoptic Dynamical Model) could produce. Also, on the basis of my own recent analysis of frictional torque and mountain torque in terms of what it might imply on NWP mid and higher latitude patterns heading through January I would highly recommend the interpretation Snowy has given in terms of the subsequent possible extra tropical reactions that would occur to the on-going MJO phase. The precisely forecasted track of the GWO is less important here in terms of taking timing and amplitude at 100% face value, though certainly very plausible in general extended outlook terms. What matters is the anticipatory grasp shown of the principles of the AAM budget and how wind-flow additions and exchanges (that are always in permanent flux) illustrate the process of net easterly winds (c/o la Nina forcing) interplaying with the effects that eastward moving tropical convection superimpose in terms of westerly wind additions Excellent post in my opinion" I sent a PM to Snowy Hibbo to thank him personally and received a kind reply from him shortly afterwards. The purpose of demonstrating all this is NOT to show a "mutual appreciation society" but to give you an idea of the potential for this much quieter and friendly thread. In fact the MOD thread was so busy last week, that our three posts (referred to above) were buried very quickly. Here, anyone can ask questions. I really hope that those of you who are "lurkers", "readers" or only "very occasional posters" will feel much more confident about contributing with their own posts as well as join in any of the discussions and debates that you chose to. You will always be made to feel very welcome.
  12. A BRIEF HISTORY OF ADVANCEMENTS IN METEOROLOGY AND TELECONNECTION SCIENCE Over the years we have seen enormous advances in meteorology and many of us often take for granted some of the theoretical and technological developments, observational equipment, instruments and other forecasting tools that have helped develop our knowledge and understanding of the atmosphere and earth’s climate. In this post, I will take a look back at some of these developments including those in the early days of teleconnection science. Ancient History Through to the Middle Ages: There is evidence of some meteorological practices from very early in our history. Around 5,000 years ago some of the writings from early Indian literature (such as the “Upanishads”) contains details about cloud formation, rain and the seasons cycles related to earth’s orbit around the sun. Then around 2,500 years ago, the ancient Greeks started to predict changes in the weather and made seasonal forecasts for crops. Aristotle produced a study which demonstrated a broad understanding of the earth sciences including climate and weather. The word meteorology stems from the Greek “meteoros” which means “high in the sky” and related to rain bearing clouds. Several books on weather forecasting followed a few years later. There are also weather references from the days of the Chinese and Roman empires. There is plenty of evidence that basic meteorological understanding gathered pace during the Middle Ages with various books, papers and charts. Some of these relate to natural events like the Indian Monsoon seasons. Various atmospheric phenomena are described and explained. A number of theories were put forward to describe the causes of extreme types of weather with detailed accounts of historic events, such as floods, drought, storms, intense heat and severe cold. Some observations and records were kept. Such things like the measurement of the earth’s atmosphere were remarkably accurate, for example the height was shown as equivalent to 49 miles which is only 1 mile out! The earliest weather diaries and daily records date back to the 13th and 14th centuries. The 15th to 18th Centuries: In 1494 Christopher Columbus experienced an Atlantic hurricane and this led to the first European account of this phenomena. Then we start to see the inventions and development of recording instruments and observations. The first type of anemometer (to measure wind strength) and the first hygrometer (to measure humidity) date from 1450. It is believed that Galileo constructed the first thermoscope to measure temperatures in 1607. The mercury barometer was invented in 1643. The first weather observation network was established in several European countries in 1654. Sir Christopher Wren invented the first “self-emptying tipping bucket rain gauge” in 1662. In 1686 Edmund Halley (the “comet” man – pictured above) produced a study of the trade winds, monsoons and identified that “solar heating” was the cause of atmospheric motions. He went onto describe the relationship between barometric pressure and height above sea level. In 1716, he suggested that aurorae were caused by magnetic effluvia moving along the Earth's magnetic field lines. Arguably, one could say that some of Halley’s theories were the early stages of teleconnection science. In 1735 George Hadley was the first to explain global circulation. In 1724 Gabriel Fahrenheit developed a reliable scale for measuring temperature with a mercury-type thermometer. This was followed up in 1742 by Anders Celsius and his temperature scale which led to the current Celsius scale. In 1780 the first maximum/minimum thermometer was invented. In 1794 the Royal Society started twice daily observations at various British locations. The 19th and 20th Centuries: From the early 19th century onwards, inventions and advances in understanding really gathered pace. I shall just mention some of the key ones (and I may well have missed out quite a few). In 1802, cloud types were described and given Latin names. In 1806 Beaufort produced his scale for wind speeds. In 1817 Humboldt produced a map of world average temperatures and the first global climate analysis. In 1820 the first synoptic weather maps appeared (see chart above). In 1823 we see the first world chart of isotherms and temperatures. In 1840 we saw the earliest theories of weather fronts. In 1844 the aneroid barometer and in 1846 the cup anemometer were invented. In 1853 the first international meteorological conference convened which led to the use of various worldwide observational standards for weather reports as well as shipping logs. Networks had already been establishing and the telegraph was used to communicate readings, records and observations – the precursor to the issuing of weather forecasts with the first storm warnings issued in 1854. In 1856 Ferrel publishes his research into winds and ocean currents (teleconnection science now well underway). In 1860 Robert FitzRoy used the telegraph to assemble daily observations from across England and produced the first synoptic charts and official English weather forecasts. In 1873 we had the first hurricane warning. In 1892 the term "El Niño" was first used when Peruvian sailors had identified warm northerly currents that were “most noticeable around Christmas” (El Nino is Spanish for the “Christ Child”). In 1902 European scientists discovered the stratosphere and Marconi issues the first shipping forecasts by radio. In 1903 Margules publishes a paper on the atmosphere as a 3-D thermodynamical machine. In 1905 ships started to submit weather reports. In 1904 Bjerknes demonstrates that weather forecasting can be based on mathematical methods. In 1920 Milanković is the first to suggest that long term climatic cycles may be due to changes in the Earth's orbit. In 1922 Lewis Fry Richardson organises the first numerical weather prediction (NWP) experiment. In 1923 the effects of ENSO (the El Nino Southern Oscillation) were outlined by Sir Gilbert Thomas Walker (the “Walker” circulation is now an important aspect of this teleconnection – see image below) and in 1924 he introduced the term "Southern Oscillation". In 1930 Molchanov invented the first radiosonde to measure temperatures up to 8 km high. In 1933 Schauberger published his theories on the carbon cycle and its relationship to the weather. In 1935 the 30 years “normal period” is used for the first time for 1900–1930 (now the 30 year “mean”) to describe various measures of the climate. In 1938 Callendar was the first to suggest that global warming came from carbon dioxide emissions. In 1939 Rossby waves were first identified in the atmosphere by Carl-Gustaf Arvid Rossby (pictured above) who explained their motion. (Rossby waves are a subset of inertial waves and you can learn a lot more about them from our teleconnection specialists during the coming few weeks). 1941 sees the first pulsed radar network in England (used during World War II) when they accidentally started to notice echoes from rain and snow and in 1944 “The Great Atlantic Hurricane” was the first hurricane to be captured on radar near the mid-Atlantic coast (it caused massive destruction with highest winds of 233 km/h, lowest pressure of 933 mb and maintained tropical storm status for 8 days and caused fatalities of 300–400 with damage of $100 million in 1944 values or equivalent to $1.38 billion today). In 1947 the first long range ballistic rocket was launched and this provided the first photographs which observed weather from space. 1950 saw the first successful numerical weather prediction experiment. In 1953 NOAA creates the National Hurricane Centre and naming hurricanes using alphabetical lists of women's names. 1954 saw the first routine real-time numerical weather forecasting. 1955 saw the first atmospheric general circulation model. The 1950s saw the introduction of weather fax charts – the US first used facsimile machines to transmit weather charts across the country and other countries quickly adopted the process. 1957 saw research efforts focus on polar areas during the solar maximum. 1959 saw the first weather satellite, Vanguard 2, which was designed to measure cloud cover but it malfunctioned. Then in 1960 we saw the first successful weather satellite, TIROS-1 (Television Infrared Observation Satellite) was launched by the National Aeronautics and Space Administration (NASA) showing photographs and pictures of the structure of large-scale cloud regimes and demonstrated that satellites can provide very important surveillance of global weather conditions from space. In 1961 Edward Lorenz accidentally discovers “chaos theory when working on numerical weather prediction. In 1969 the Saffir–Simpson Hurricane Scale was created (showing hurricane strengths on a category from 1 to 5. Back to teleconnections and in 1969 Jacob Bjerknes described ENSO as “an anomalously warm spot in the eastern Pacific which can weaken the east-west temperature difference, causing weakening in the Walker circulation and trade wind flows, which push warm water to the west”. In the 1970s weather radars were standardized with a development of networks. In 1971 Ted Fujita introduces the Fujita scale for rating tornadoes. In 1992 computers were first used to draw surface analyses and 1998 saw major advances in which allowed for the digital underlying of satellite imagery, radar imagery, model data, and surface observations improving the quality of surface analyses. Into the 21st Century: The 21st century has seen major leaps forward in the use of technology. The accuracy of the current official 5-7 day detailed forecasts are similar to that of 1 day forecasts from 50 years ago. The accuracy of experimental 8-10 day forecasts is comparable to that of the 5–7 day forecasts when they were first officially provided 15 years ago. Even with the use of super computers (like the Met Office’s £97m 2017 model shown above) and other sophisticated forecasting tools it is thought that that accuracy of detailed forecasts much beyond 15 days will be a struggle to achieve in the foreseeable future. This is where the development and application of some of the teleconnections can come into their own. An often misunderstood aspect of this is that we are not looking at detailed weather forecasts for any particular location but at changes in broader weather patterns. It is by analysing the background signals and the drivers that control the model output where we can make the biggest advances, including longer range and seasonal forecasting. For those of you like me, who will learn on this thread, understanding how angular momentum (AAM) and the GWO (Global Wind Oscillation) in conjunction with the ENSO state, influence the weather patterns, where ridges and troughs set up, where blocking occurs and how the Jet Stream behaves will open your eyes to some exciting possibilities. Over to the specialists! I want to learn a lot more from our specialists about this fascinating subject. I also want to gain a broader knowledge of some of the other teleconnections. The one thing I've learnt over the years is never to dismiss any theories however bizarre they might seem initially. So, I always keep an open mind even if I'm pretty sceptical about certain things. This is, of course, a fundamental rule that applies to all scientific research and to all those advances and inventions that I outlined in the “history” part above. Unfortunately funding issues (who controls the purse strings) and politics (who controls the agendas) very often clouds the picture, particularly for key issues like Global Warming and Climate Change. I can’t wait to participate in some of the discussions that we hope will develop on this thread.
  13. LEARNING ABOUT TELECONNECTION SCIENCE AND BACKGROUND SIGNALS Welcome to a brand new specialist thread. The vast subject of teleconnections is a fascinating one. Some of the science is quite complex and is not really well understood by many of us. It is very easy to dismiss the purpose and usefulness of the many teleconnections and to misunderstand the role that they play in advancing meteorological developments, long range weather forecasting and with climate change and global warming. Just to list some of the teleconnections we have: the ENSO state (El Nino and La Nina); Angular Momentum and the GWO; the MJO; the QBO; the Jet Stream; Stratospheric Weather – Temperatures, the PV and its relationship with the Tropospheric PV; Ocean Currents; Sea Surface Temperatures; Arctic and Antarctic Temperature profiles; Sea Ice and Snow Cover extent. The main (but not exclusive) focus of this thread will be on most of these but particularly the first few listed. It’s all these “background” signals that to a lesser or greater extent drive the model output. Some are more dominant and are the “drivers”, some may at times play an assisting role and at other times an interfering role. It is a continuous learning curve in observing and understanding how all these processes interact and what impacts they are likely to have on the broader weather patterns. Sometimes it’s a case of a cause and effect relationship which can challenge existing understanding. There are many other teleconnections such as Solar Weather – solar bursts, solar flares and sun spot activity and cycles; Space Weather – gravitational pulls, electro-magnetism and impacts on the earth’s magnetic fields; Volcanism – major volcanic eruptions and earthquakes; Global Warming, Climate Change and Human influences like CO2 emissions and various forms of pollution, deforestation, acid rain; Livestock influences – producing ammonia, methane and many other gases; Thawing permafrost and tundra - releasing huge methane deposits that have probably been frozen solid for at least several thousand years; various other oscillations and cycles and I’m sure that I’ve missed some others. Most of the teleconnections interlink with each other to some extent but some of the relationships are only just beginning to be understood. The main purpose of this thread is to encourage a whole spectrum of readers and posters to contribute. This will be anyone from professionals (working or retired), the various specialists in these fields, keen amateurs like myself who might have a basic but limited understanding of some of the processes but wants to expand their knowledge and especially everyone else who wants to learn more about the subject. Even if you are a complete beginner you will be very welcome on this thread and made to feel at home. It is intended that we’ll have a good mixture of posts pitched at various levels of knowledge and understanding. There will be a “learning area” with some of the basics described (including a list of the commonly used terminology and abbreviations with short definitions) as well as a “technical area” covering much more advanced parts of the science. Some of the specialists have a very good understanding of parts of this subject but they may well be learners themselves in many other areas. You should feel free to ask questions especially if there is something that you do not understand and want it explained. Anyone can come forward and provide answers to these and a number of the regulars, who’ll be on here from time to time, will try to ensure that nobody is ignored. There may be a short and simple answer or a longer post may be required which would take rather more time to deal with. If no one can provide an answer, we’ll do our best to point you in the right direction and refer you elsewhere (such as one of the other specialist threads). We want to promote and encourage open discussion and debate. There is no problem if anyone disagrees with a particular view but please ensure that you explain why you do (with evidence if appropriate) and in a very friendly and respectful way. Nobody should feel at all uncomfortable and we’re hoping that some of the “silent readers” on the winter model thread (and other threads) will feel much more confident about posting and contributing to this thread. We can all learn more right here. I intend to create a library where a list of all the papers and links that poster’s refer to and provide will be indexed for easy reference. In time, with the help of some others, I would like to produce an “abstract” with a very brief summary of what some of the most relevant and popular papers cover. A few of you may know that @chionomaniac created a specialist teleconnections thread back in 2012. This was archived about 18 months later. There are some fascinating posts in that thread and most of them are still highly relevant today. There are sub links to various papers there and, in time, some of these will be brought across into this thread. I’m hoping that Chiono will be a regular contributor on here. In the meantime here is the link to that NetWeather archived thread for permanent reference: https://www.netweather.tv/forum/topic/73911-technical-teleconnective-papers/ or you can just click on the chart below: The pace on this thread is likely to be much slower than the model thread, perhaps more like that on some other specialist threads like the stratosphere thread. We do not intend to compete with any other thread and, in fact, we would hope to compliment those threads. Some posts may well be suitable for going on more than one thread and “cross-posting” will be encouraged. For example, I will continue to post on the model thread from time to time but I may copy particular posts on to this thread (and vica-versa), perhaps so that some points can be discussed and debated in this quieter environment. When I say “we”, although this was my initial idea, I have spoken to some of the teleconnection specialists and they all wish to support and embrace this new project. So let us get this up and running for everyone’s benefit. So this is definitely not about me and I will simply be one of the quite regular contributors, keen to learn myself and wishing to be involved in some of the discussions. I will be following up this introductory post with another post looking at the history and developments in meteorology and where teleconnections fit into this. Some of the regulars will also be producing posts shortly after this thread goes live. This includes @Catacol and @Snowy Hibbo amongst many others. As this thread evolves, I hope that we shall see more and more contributions, so please check in repeatedly to see where we have got to. Feel free to spread the word and relax, learn and enjoy. Bring Back 1962-63 (David)
  14. WHERE DO WE GO FROM HERE? In this post, I want to very briefly review the short to medium term period and then I will look slightly further ahead. I am very busy, so I will not have time for one of my thorough cross-model analyses and anyway, there has been a far larger number of posts than usual examining the model output (can’t think why!). I will take another look at northern hemisphere temperatures again (some much better news here for us going forward). It’s a month since I last updated my Arctic ice and temperature indicators, so I’ll do this now and we have the very latest monthly Arctic report released yesterday (more very bad news here). Despite all this, I will be painting a much more optimistic picture for later this month. SHORT OVERVIEW ON THE UPCOMING COLD SPELL: Those that have been reading my posts and reports will know that I am like the majority on this winter model thread in that I love cold and snowy weather. I am always searching for colder patterns and set ups but I do try to be realistic and provide some balance. I did say in several recent updates that I would be surprised if the forthcoming cold spell lasted for much longer than 4 or 5 days. The rising heights to our north-east, the Scandinavian HP and a possible easterly of sorts only look to be pretty temporary features given the backgrounds signals. We may get several days with a battleground scenario when the Atlantic tries to fight back and comes up against a “relatively” cold block. Some snowfall in parts of the UK seems likely but probably far less than many are hoping for. In fact, if the breakdown proves to be a slow and complex one this might be our best chance of getting something rather more memorable out of this. How quickly it then warms up is still very uncertain and I feel that the models may struggle with this right up until T+72, which should make the new short term model thread much busier next week than it has been so far! I do not see the cold spell being extended into the following weekend but that does not mean that we’ll have many days of very mild weather either. The jet stream should break through and we may be back to a pattern that we saw for much of the last month with alternating short colder and milder spells. This time of year, Polar Maritime air can be potent enough to produce something more wintry (but see my Arctic update below). Of course, I would love to be wrong about all of this but I’m trying desperately hard not to be persuaded by some of the eye candy that we have seen during the last few days, as deep down, I just feel that the models have not really latched on to the background signals (although they may just be starting to). On the other hand, do not feel too gloomy – please read on! LOOKING SLIGHTLY FURTHER AHEAD: Without going into my usual longer detail, the background signals do indicate that something better might be in the offing. Just re-read the excellent recent posts from the likes of @Tamara, @Glacier Point @Catacol, @Singularity, @Snowy Hibbo as well as @carinthian. The down tick in angular momentum looks to be very temporary. Just as before Christmas when the signals suggested the rising heights to our north-east for early January (which “had” been extremely well sign-posted), then the down tick in momentum indicated that these heights would be replaced by a flatter pattern, we once again see a “likely” uptick in momentum (this is obviously not certain and is a forecast at this stage) which will again favour stronger blocking to our north-east. The timing for this is, as usual, going to be very problematic as GP highlighted this morning. I’ll be looking out for further updates from these posters on the AAM, GLAAM, GWO etc. How the unusual (and recently changing) La Nina pattern interacts with the AAM (etc.) is also very important. The east Pacific based La Nina with the cold current upwellings there and the now almost average ocean temperatures in the central and western Pacific have created a profile which is unlikely to follow the normal Nina winter behaviour and impacts. No more detail but just to say that the current set up is much more likely to have favourable impacts compared to the usual Nina ENSO state. Then we have the recent NOAA reports that have suggested a much more lively MJO as it moves out of the “circle of death” and progresses through phases 2 and 3 at a steadily increasing amplitude. Given the timing of the 30 to 45 day full cycle, we should reach the important stages of 7, 8 and 1 later this month. Providing the MJO doesn’t die again, then that should substantially assist with establishing HLB patterns. Ideally (for coldies), we would like to see the MJO remain in those key phases for as long as possible at decent amplitude. Then we have the thoroughly disrupted tropospheric PV. There has been a huge battle for the seasonal peaks in the strength of the PV and the Jet Stream against the disruption and frequent injections of WAA into the Arctic. We have seen regular ridging of high pressure into the Pole but not sufficiently (yet) to produce much more widespread HP up there. The stratosphere “may” be starting to play ball too. Remember this is NOT all about a sudden stratospheric warming (SSW) which is still a “possibility” for later in the winter”. Currently, it is the strength of the strat PV and how that might imprint on the trop PV. The previously predicted “reconnect” has (fortunately, it seems) not been going smoothly. Then we have had some fairly brief downticks and upticks in strat temps at several levels and finally there have been some minor and short-lived warmings that have come and gone. (I’m still not able to comment coherently on things like wave1 and wave 2 impacts – so just study the strat thread for that). Bringing all this together, I feel that frequent disruptions to the trop PV will continue: Just look at these two GEFS ensemble panel for day 10 and day 15 as an example: GEFS 6z ens Panel T+240 GEFS 6z ens Panel T+384 Once again we have varying degrees of disruption, including several fully split PVs and very few showing anything near to a well organised PV. Add to this the fact that the strength of the PV and the Jet Stream will have passed their usual seasonal peaks and from mid-January they usually steadily become much weaker again. Then add in the likely uptick in AAM (and GWO moving towards phase 4), the MJO progressing towards its more favourable phases as well as the eQBO favouring polar easterlies and HP near to or over the Pole, then we might have, for the first time this winter, all these signals starting to become far more harmonious. Timing of the “possible” (I feel “probable”) impacts is not straight forward but there could be an evolution from mid to later in January. Equally, I feel that once we manage to find this path, it could evolve pretty quickly. I’m still hanging my hopes on a cold regime becoming established later this month and that this time it will not be a short-lived affair. In fact when you read my next section, I’m going for it to last for much of February too (but I had better not get too carried away about this, otherwise somebody, like Knocker, will literally carry me away!). All this before a possible SSW impact perhaps for mid-February. NORTHERN HEMISPHERE TEMPERATURE OUTLOOK: Last week I provided a post on this subject and another one on European temperatures which should have made it clear how marginal the uppers and much of the surface cold are likely to be during the coming cold spell. What I said in the first of those reports was how much more encouraging things looked from around mid-January onwards. So, given everything that I’ve said about the signals above, let’s have a brief update on the medium to longer term northern hemisphere temperature profile. I’ll compare current, day 10 and day 16 charts from GFS, ECM (only to day 10) and the GEFS panel for the 850 temperatures and substitute GEM (only to day 10) for ECM for the surface temperatures (as Meteoceil do not show ECM charts for these in this format). I have deliberately chosen alternative models to the GFS as they have (or at least "had") been favouring a more extended colder outcome. 850 Temps: GFS 6z T+6 ECM 0z T+0 GEFS 6z ens Panel T+6 The models show the extreme cold that pushed down through North America as far as the southern USA in recent days. Apart from Greenland there is just insufficient cold to go around. Even Siberia is slightly less cold than usual right now. Europe has very little cold to tap into. GFS 6z T+240 ECM 0z T+240 GEFS 6z ens Panel T+240 By day 10 we are already seeing quite dramatic changes! The GFS shows North America giving up its monopoly with the deep cold there easing. The deepest cold is re-establishing itself in Asia and Russia. This change is very strongly supported by the GEFS. In fact only 3 of the ensemble members continue to show greater cold in North America and even those show increased cold in Asia. The ECM shows a similar but rather more balanced pattern with a more equal distribution of cold in both continents but with Asia just starting to gain the ascendancy. GFS 6z T+384 GEFS 6z ens Panel T+384 By day 16 we only have the GFS to go on now but it shows the continuing evolution. By then "all" of the USA has well above average 850s (none below zero!). Even Canada only has slightly sub zero 850s with the lower (but much higher than now) values confined to the Canadian Arctic, the Arctic around the Pole (see later for fuller details) and Greenland have also warmed. So where has all this cold gone...yes, across to Asia, Siberia, Russian and towards Europe! "If" these conditions verify, then these parts will have their lowest values so far this winter. Look at those sub -12c 850s extending to Iceland and into Scandinavia. Then it would only be a question of delivering the right synoptic patterns (preferably north-easterlies or easterlies which I feel are more likely than not later this month) to set up to drag in some really low 850s with no "marginal" conditions to worry about. The ensemble means generally provide a lot of support for this. Only two of them show any deeper cold in North America. Another one has the deepest cold over Greenland but still with plenty of lower values in Asia.Three more have a fairly even distribution of cold but the vast majority have the coldest 850s over Siberia, Asia and Russia. Nearly half of them already show sub -4c or lower values across Europe (a couple include the UK). There are several with some sub -20c 850s already pushing steadily through western Russia and on towards Scandinavia and northern Europe. I really hope this lifts the gloom should the models continue to downgrade the upcoming cold spell. This change is extremely encouraging and obviously needs to be monitored closely. 2 M Surface Temps: GFS 6z T+6 GEM 0z T+6 GEFS 6z ens Panel T+6 Moving on to the current surface temperatures, we again see that intense cold spell currently hitting North America with far less deep cold in Asia but at least Siberia has its usual deep surface cold for this time of the year. GEM is similar - watch out for those black areas which look quite sinister but actually on their charts never go down below sub -28s (the lowest they ever show), whereas the GFS "white" areas go down to sub -40s. Please note that the GEFS panels for surface temperatures only show the enlarged Europe view (the Northern hemisphere view is not available on Meteoceil charts). GFS 6z T+240 GEM 0z T+240 GEFS 6z ens Panel T+240 As with the 850s. the surface temperature distribution has changed significantly by day 10. Remember that North America will hang onto to some of its surface cold unless the jet stream pushes across some much milder air from the Pacific. By then, the deepest cold has moved into central and northern Russia and way down to south-west Asia with some unusually cold conditions down there. The cold extends towards south-eastern Europe. The European pattern is shown in more detail in the GEFS panel. Actually rather more members show colder conditions pushing into eastern Europe and Scandinavia compared to the GFS operational run. GEM is broadly similar but with deeper cold into western Russia compared to GFS. GFS 6z T+384 GEFS 6z ens Panel T+384 By day 16, North America has continued to warm up. In fact the southern and central states are well above zero by then and even northern USA and southern Canada are barely below zero. North-eastern Canada and Greenland have some deep cold but again, the most extensive deep cold is well and truly established across Asia. In fact the extent of the white area of sub -32s over Siberia, much of Russia and parts of western Asia is the largest that I have seen for many years (unless someone else can find something lower?). The area of sub -40s within that is also the largest for a very long time. Further west, towards eastern Europe, surface temperatures are widely just below zero. The cold air has extended across Scandinavia. Much of central and western Europe and the UK are rather cold (mostly 0c to 4c). The great news is that we should have some deep cold in place not too far away to our north-east and east. The panel members mostly revolve around this pattern with an equal number showing slightly colder conditions closer to the UK and others slightly less cold conditions. Arctic Sea Ice News and Analysis: During last July the Arctic sea ice extent briefly hit a new low for that time of the year challenging the overall record lows seen in 2102. It reached its lowest point in mid-September when it was the fourth lowest on record. There was a limited recovery during October and through November and an even slower rate of recovery during December and in mid-December this winter (2017-18) was actually the lowest! Right now, only last winter (2016-17) was slightly lower still. This can be seen in the charts below: Source: National Snow and Ice Data Center (NSIDC) The latest monthly update (for January) was published last week and makes for compelling read but with some absolutely dreadful news for the Arctic sea ice extent. "President Trump - you "must" take note! Please use the link below which also shows all the charts (and many other details): http://nsidc.org/arcticseaicenews/ Arctic Current Sea Surface Temperatures (SSTs): SSTs January 3rd SST Anomalies January 3rd Source: NOAA Marine Modelling and Analysis Branch The anomaly chart shows that there is a wide area of open water in the Arctic with well above surface temperatures. The SSTs need to be below the -1.5c threshold (the purple colour). Sea water will start to freeze when it is below -2c but that is for normal salinity. There is slightly lower salt content in the Arctic (mainly due to ice melt) and the threshold is nearer to -1.5c. There are some areas with SSTs well above freezing and the current anomalies are widely over 4c above average and up to 8c above in places. Unfortunately, although the SSTs themselves have fallen very slightly, the SST anomalies have risen even further during the last couple of weeks (the normal seasonal decline through the winter months), some of the anomalies have increased – eg: now over +8c around Svalbard. These higher SSTs are a legacy of the 2015-16 winter when the Atlantic jet stream powered well into the Arctic for much of the first half of winter. This shifted much warmer than average currents right up to the edge of the ice sheet. This strong anomaly has persisted for 3 years and is exceptional and comes on top of the already generally warming Arctic. Unless the SSTs reduce substantially, the anomalies might be carried through to next summer and into a fourth winter. There is a small area of the North Atlantic, mostly south-east of Greenland with a negative anomaly. Unfortunately I have run out of time to produce my detailed analysis of Svalbard temperatures (these will appear again with my next Arctic update in several weeks time) but needless to say those readings just add to the extremely worrying Arctic temperature profile. Even though this is probably good news for us in the UK in seeing more cold air here, I'm sure that most of us do not want to the Arctic warming at such a dramatic rate. Well, did I say a less long report – you should know me better than that! Once I get going, I just cannot stop, especially when I really like the look of some of the signals that are appearing. I sincerely believe that there is no need to get too concerned if the upcoming cold spell fizzles out quite quickly. The ongoing events are highly likely to give us at least one or more bites at the cherry. It’s even possible that we can extend the near term cold spell and shorten the gap to the more prolonged cold. Nothing is set in stone and I have well and truly put my neck on the line! So, if it goes wrong, tie me to the final piece of the Arctic ice sheet as it drifts off into oblivion early next summer! It may be a few days (or longer) until I post again on here as I’m working on an exciting new project that you’ll hear about during next week.
  15. LOL. It's back to running my business from now on, so I'll have much less time to post - they'll be less frequent and (probably) less long, much to some members' relief! Very craftily, you have drawn me into writing this post! I'll stick my neck out very briefly (without posting charts or referring to the detailed evidence to support me). My current take is that it'll be good news, then bad news followed by very good news for coldies. The easterly (of sorts) "may" deliver a few cold or very cold days and unpredictable (at this range) amounts of snow. Then a battleground scenario with the Atlantic fighting back and possibly quite a snowy breakdown. Then back to a rather flatter pattern and an unsettled regime (perhaps anything from 5 to 10 days or so) with a mixture of milder and colder days with some Polar Maritime air in the mix at times. Then, I see the change to a generally colder regime evolving later this month and in place towards the end of January (perhaps a little sooner) and continuing well into February. The background signals (yes, back to those) "had" been conflicting and rather uncertain but in reality hardly changed with just a short blip or delay in the likely broader pattern changes (always timing issues with these). There is now much stronger evidence that will shall see greater harmony going forward. The AAM temporarily weakening and then strengthening; the unusual Nina ENSO state (initially supporting the front-loaded winter which we had to some extent, then taking on the east-based Pacific position (which may well assist with the Pacific profile and impact on downstream patterns and interfering with the jet stream and favouring ridges and blocks to set up); the strat temps (where we did have some slight early winter warmings) temporarily falling and now forecast to rise again and the strat PV eventually downwelling and impacting on the already thoroughly disrupted tropospheric PV (please refer to @chionomaniac's,strat thread update 2 days ago on this with perhaps an SSW as we enter February but I feel that this "may" not be necessary this time) the MJO at last coming to life and set to move into it's key phases of 7,8 & 1 (probably at decent amplitude this time, assisting with HLB patterns) towards the end of January (see @nick sussex's comments including the NOAA report as well as several other well respected posters on this); the jet stream and PV will be passed their usual seasonal peaks by then anyway. I have simplified all of this and parts may not be completely accurate but there is plenty going on behind the scenes that drives the model output. So, nothing set in stone but far more in the offing for coldies than we've seen since at least 2013. I fully expect the models to struggle initially with picking up all these changes - in the length and potency of this weekend's (and into next week) cold spell; the timing and nature of the breakdown during next week; the length and nature of the intervening less cold/milder interlude; sniffing out the signal for the change to the cold regime. I imagine that this post will provoke some very mixed reaction. I'll address that when I next produce a longer post. Meanwhile enjoy this very exciting period of model watching.
×