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Showing content with the highest reputation on 21/12/17 in all areas

  1. 59 points
    The idea that the signals 'have gone wrong' and previous posts don't tally with earlier posts would be laughable, if it wasn't so misleading and demotivating to (all) those who have made those posts. For my own part, I'm very deliberately posting 'the whole book' written one month past which assessed the possible problems the patterns this season might encounter in terms of the favoured cold weather this thread (largely) craves. Its staggering, frustrating, very annoying and equally demoralising that so much time can be wasted attempting to provide so much information in voluntary time but to persistently find a name banded around with quite different interpretations - and especially an inability to take one post in context of the next - some simply lazy and glazed over and can't be bothered to read, and others which are frankly trolling deliberate misinterpretations. So, another long one (I'm afraid) of intending to manage expectations before returning back to the rollercoaster sidelines My own perception of the start to winter. (like any other season in terms of weather preference), largely differs from most because I am far more interested and curious how the signals play out (either way) and not how cold and snowy it might get. So I will have to be forgiven for a different tone that frankly intends to neither optimistic or pessimistic, but simply hopeful objective how I see it. There is neither the time or inclination to get absorbed in the daily swathes of NWP operational and ensemble suites - but instead the usual non NWP approach is most helpful to me. In the final analysis anyway, the signals dictate the models, not the other way around. Apparently consensual ensemble suites gauge assessment based on a moment in time captured, but they are prone to switch direction like shoals of fish when they realise something different may be going on... So, for what it may be worth: Sorry no time for links. Atmospheric angular momentum tendency (essentially in context referring to the turning force of the jet stream) has tumbled back with lack of tropical convection (MJO) focus allowing easterly wind inertia to return to control the atmospheric circulation in line with La Nina consolidating at all levels in the Pacific. The SOI is consistently +ve and there are colder waters to upwell and strengthen La Nina into the close of the year The Global Wind Oscillation (which represents a plot representation of global wind flows as referred to above) in reflection of all this, has progressed from quite an amplitude Phase 8 and is set to hover around Phase 2 for a while. This slow/stationary orbit underpins the modelling over the coming days in terms of the very big signal for a very amplified holding Atlantic ridge - and certainly favouring a cold pattern sustaining into the medium term as the vacuum occurring upstream slams on the brakes with jet flow rapidly decelerating In terms of the stratospheric feedbacks though, the question mark in my mind is the extended hints of the Pacific pattern starting to show the first signs that La Nina is going to tighten its control from upstream with the building of the Alaskan ridge. On that basis a highly anticipated two week stratospheric forecast is just that, and on the basis of potential upstream changes that ultimately spell return of the jet, it cannot be wholly assumed it will automatically favour this side of the pole as the Pacific pattern starts to take control. So I don't personally agree with some of the views being expressed that this is a "good thing" for downstream prospects in terms of sustaining a cold weather pattern beyond the early to (possibly?) mid December period. Its a typical La Nina development that often happens as wavelength cycles occur with the change of month and season and has the effect of increasing Canadian cold and re-booting the energy into the downstream polar jet. Such inications are minority model solutions at the moment that show increased upstream flow in FI, but I think its not a case that they are automatically wrong, simply maybe on the progressive side. And I would be highly cautious of 100% confident assumptions then return energy will automatically split and encourage trough disruption under the Atlantic ridge On that basis I'm not sure that any equal assumption (however valid) can be made that the present amplified pattern has a sustainable feedback. Or at least not sustainable without a further eastwards moving MJO catalyst, to engineer further tropics>extra tropical rossby wave train and set up further downstream amplification via +ve MT and then, just as importantly in turn externally pressurise the polar stratosphere. Even the freeze of 2010 ended on the basis that no follow up occurred to the high amplitude MJO event of October and that led to the rapid taking of control of the default La Nina Pacific ridge and return of polar jet flow after Christmas So the La Nina default will not favour any undercut of -NAO automatically. The upcoming pattern is a traditional (extra amplified) mid latitude ridge pattern. The irony is that the higher AAM pattern we have been seeing of late has actually featured something of a Greenland High and an attempted -NAO (albeit west based). Its no coincidence that falling AAM redistributes the blocking pattern into the Atlantic. I think this has already been forgotten by quite a few because of the pretty charts at the moment However much the warm air advection from this ridging may perturb the troposphere/boundary and help prop up the poleward nature of the ridge in the short and medium term, the increasing upstream amplification in the Pacific that will carve out the default La Nina ridge will, eventually, increase cold air advection upstream and focus jet energy into the polar branch. That is not going to assist cold air advection downstream and both negate stratospheric destabilisation this side of the pole, and transfer the weakness to the Pacific side. This is an old and familiar story, and though we are certainly in a different place to last winters weak La Nina, the possibilities remain the same with the arctic in such an alarmingly fragile state. Its getting increasingly hard for the whole hemisphere to be cold - there is simply not enough cold air to go around. Something, and somewhere, has to give The importance of the Aleutian Low and Siberian High moving forward in terms of cold air feedbacks have been identified a few times on here as a means to sustain a cold pattern into winter proper. Any Pacific heights, as a key part of an arrangement of circumglobal La Nina mid latitude ridges and polar jet flow, are counter intuitive to this. The stratospheric pathway can certainly override the tropospheric winter La Nina effects, but its going to require tropical forcing to play ball and come into play just at a time when the upstream pattern shows signs of coming back to life once more. Strengthening La Nina and changing seasonal wave length changes are going to become increasingly resistant to this the further we head towards January and especially beyond. There is no certainty either way, and whilst the pattern could sustain in a few ways yet - the "quick fix" I spoke of in the MOD a couple of weeks could easily still be just that. At the moment I see things much as I would at the end of a warm La Nina Spring, that so often does not transfer to a warm La Nina summer. That said, there is more to encourage a cold pattern, certainly to start, beyond what the weak La Nina went on to deliver last year - but I don't see the straightforward path to sustained cold nirvana many others see. Ciao I could have posted much more from various other posts which have gravitated and returned back to this theme, but it still wouldn't increase the chances of having them put in the right context. Now, a whole lot of signal evolution and model output has obviously gone under the bridge since even the last week of November and many, many others have contributed large amounts of time to try to give best perspective. Lots of different posters, some with great NWP insight, others using non numerical methods. But in between the ever increasing signs of a theme towards possibilities to cold weather as a recurring theme this winter, there have been REPEATED posts that have returned to the early cautionary theme of the whole bolded post above. Simply speaking, there are still uncertainties ahead which some are rightly referencing, but that crossroads I banged on about is arriving and frankly there should be no surprise that the signal, tea leaves, teleconections (call them whatever) have come to roost in the way described above and are not necessarily following the 'straightforward path to sustained cold nirvana many want to see' that was posted 4 weeks back Please, to those with lack of attention span, note the italics in the previous sentence. There is of course a whole lot of this season to go yet, and much can still (and will) happen either way - and who knows sooner or later. But please no-one act surprised or blame the 'tealeaves' for being wrong. Blame a skewed, frost tinted or addled mind instead - the pendulum has swung to and fro with the upsides and downsides (this is the UK after all) but don't anyone tell me (or anyone else) they have been misled. Its not my fault (or anyone else) there are selective agendas and a few who are so insecure they need constant 'will it snow' updates who only want to hear what they like. There is the weather, and there is also a life. One that is often more serious, more problematic and can have much greater repercussions than whether or not it snows. I've seen it said that weighting two different scenarios is some kind of ploy so as not to be wrong either way. Er,no - its simply saying things as they are and giving an honest opinion. Like lots of other opinions. Its not about right or wrong, its meant to hopefully be about informative contributions, and not to pander to tribal allegiances. I'm not wasting any more time and energy with further explanations or even current analysis - its a hiding to nothing continually having words put in mouth by a vocal percentage who keep acting bemused or even cheated because (allegedly) they had been promised their cherished weather and its disappeared, or hasn't happened yet. Whatever. Or who offers nada themselves but sit and carp at others efforts. Why bother? But there are plenty of very good (also equally non-egotistical) posters on this forum, many of them on this page each day. I suggest keeping looking out for who they are and those referred to above maybe who, either deliberately or simply lazily have selective thinking, paying them the respect they deserve. Otherwise they too are going to get fed up very fast and not bother also. I know some who already feel that way - so this is not just another one-off paddy fit. To the rest (of the large majority) on here, I hope you all have a lovely Christmas
  2. 28 points
    So if your so certain of a mild and wet January, and now Glacier point also saying a similar theme yesterday, why was in only a week maybe 2 at the most that him and others were posting very good reasoned out posts all pointing to our north east in the new year, very confident forecasts explaining why it looks nearer enough a dead cert??? This happens every year and it seems peeps never learn. Signals and teleconnections seem to be as fickle as anything else imho. Can you or glacier point explain what's suddenly gone wrong on what seems to be a chatostrophic scale? Cheers
  3. 17 points
    That’s a great shame Tamara. I find it quite disturbing how an individual who has done extensive reading, starting from nothing, has such a wealth of knowledge. And is ridiculed you can’t argue with the science, Tamara, always highlights the caveats - no wonder she doesn’t forecast what makes it all more baffling. This one-upmanship needs to stop at once, and TEITS I’ve seen very little signal of very mild SW’ly so a bit of a cherrypick 10 days out.. I’ve read it’s a bad as it gets? Hyperbole quite frankly a 3-4 day cold snap/spell is now firmly agreed upon and with that the chance of snow even possible away from usual places.
  4. 17 points
    Let me see if I can help, the cyclones that they are referring to regarding interference are those occurring in the Indian Ocean. That body of water is included in forecasting MJO phases. What we have are several cyclones moving poleward, it is unclear what amount of energy is contained in these storms, therefore difficulty in calculating effect. Initial forecasts stemmed from that enormous Pacific energy wave in mid October as shown below This in turn due to its magnitude created a split in PV via Tropospheric upwelling. It was a very large sigma event. Since then the Pacific had went dormant until now. Typhoon Tembin has now formed as forecasted. It is this typhoon that will create the modelled Pacific WAA and upcoming -AO. Models have forecasted a 2nd Pacific NW Typoon which has not materialised as yet. There will be two pulses of significant statospheric energy waves. The issue now is what magnitude of energy will they contain. At present they look to not contain enough to attain a full reversal at 60N @ 10 hPa level. Hence the readjustment of GP’s and S Murr’s thoughts. There will be cold incursions from this event but unlikely to hold unless energy contained inside these wave breaking phases is misjudged by models. Finally January is not a forgone conclusion until we reach the 20th day of the month, but the remainder of December is. The Pacific could very well go into full activation mode and create a SSW. Energy contained and storm activity are the unknowns, hence the readjustment to forecast. Personnally I’ll be looking at the next phase of Typhoon/cyclone activity after this one around the 10th Jan 2018. Then we will have a better understanding of what’s to come for the UK.
  5. 15 points
    You miserable bunch this morning. Don't give up hope, nothing is set in stone regards early - mid January. Pret15 keeps the faith
  6. 13 points
  7. 12 points
    I share your frustration Tamara and cannot pick fault with anything you said in your post. I really do hope you continue to contribute on this forum as your analysis and expertise is second to none as far as I am concerned.
  8. 12 points
    Im not sure I agree with some of the posts this morning. Between Xmas and the New year its likely to be unsettled with snow on higher ground in the N. Im not sure I would refer this as stormy though just bog standard typical zonality. Worringly if you're seeking a cold spell for the New year the outlook could become even worse.as I can see pressure rising from the S with the jet taking a SW-NE trajectory. This will result in very mild temps spreading across the UK into Europe. I continue to be amazed at just how much warmth is being predicted especially for Scandi, Siberia. Only positive for the New year is the ouput can only get better because it cannot get any worse.
  9. 10 points
    For reference sake this is glaciers very good post from the 13th dec, what's changed so much since then? From what I can tell the GWO isn't reaching phase 8 like expected and this could be the biggest driver? Thanks
  10. 10 points
    Latest MJO and PNA Charts: Just a short one from me, for a change! I don't think anyone posted the recently updated MJO charts today. SOURCE: NCEP/GEFS - NOAA SITE SOURCE: http://www.njstrongweatherforum.com/t511-what-is-the-mjo-really Still a lot of uncertainty regarding whether the true MJO signature is being masked. I'm a little baffled by the different GEFS traces on the two charts (the green lines on both of them). I put the sources up but all the data comes from NOAA. The amplification in phase 1 is greater in the second chart! For the same index surely one of them must be in error? Anyway quite a mess overall. I'm sure that @nick sussex will shortly find a report from NOAA on this or at least their thoughts on the current state. SOURCE:- NOAA I copy the Dec 20th chart and it keeps reverting back to Dec19th. My comments are correct! Most of the PNA ensemble members are going positive again towards the New Year, having been briefly negative for a few days. I think that this is bang in line with part of what @Tamaraand @Catacol were predicting in their recent posts towards the end of last week.This is what is starting to show up in the model output with fairly low pressure close to the Aleutians and a strong ridge through Alaska and into the Arctic - a classic +PNA signature. Any more on this will be beyond my pay grade!
  11. 9 points
    Today's (GFS) tropical outlook underscores why we are heading for a substantive drop in angular momentum. The only bit of forcing being 60W, lots of easterly wind addition across the Tropical Pacific and northward momentum transport. To rub this in, GFS also predicting a -ve zonal winds developing in the upper stratosphere over the Equator, which will add easterly inertia to overall angular momentum budgets. Net result is that were are heading for GWO phase 2 New Year onwards. As a basic template, low to the west, ridge to the east but not far enough west or north to bring about an easterly flow and not conducive for cold outbreaks to our east.
  12. 8 points
    @tamara - you shouldn’t be surprised that much of your posts are not read properly. I think the problem you had over the past few weeks was that it was ‘cold on the ground with snow’ and some posters here and the met Office were seeing cold ahead in their models etc for jan. You wanted to remain on the fence but I felt that developments in the Pacific pushed you into landing on the ‘cold side’ going forward. Whether that’s the right or wrong decision remains unknown but some are bound to sadly react badly to ‘apparently ‘having their snow taken away’ from them !
  13. 8 points
    I don't blame Tamara for giving up at all. If I was her I'd do the same. The teleconnections are what drives the Nwp. All Tamara has ever done is give her honest opinion of what they are suggesting at any given time along with what could scupper that outcome. The same as GP. This forum will be very very much the poorer without her.
  14. 8 points
    Thanks! Me, HC, Northern Strath, Northern Lights etc away out to Chanonry Point later to sacrifice Sean Batty to the snow Gods.
  15. 8 points
    An interesting comment that, re the output from Glosea, how do we know what it was suggesting as we have no sight of it? In the fairly reliable time frame, and already commented on re the 500 mb anomaly charts. They, that I can get hold of, other than NOAA, both 6-10 and 8-14, have changed emphasis somewhat but in general a strongish westerly Atlantic flow from the bottom of the main Canadian trough into the UK then on into a relatively shallow European trough, on some, into the Mediterranean. So other than the 2-3 day colder spell post Xmas, and quite probably similar developing in the 2 week period behind deepish surface lows then no major cold outbreak seems likely. beyond 2 weeks I leave to folk with a much greater understanding than I have. If I may as an old 'un, make an observation on some of the posts re deep cold, what interests me is why, with UK Met models being constant in the 2-4 month outlooks re overall temperatures, upper air patterns, is why we got such a fairly deep cold outbreak this month. Nor have I any idea why UK Met, went fairly consistently for the colder option in their 6-30 day outlooks, in spite of what their 2-4 month input must have shown. Quite intriguing but I no longer have any contacts in the senior man's area so I will probably never know! usual links below along with the ECMWF 500 mb anomaly charts via Meteo-c http://www.cpc.noaa.gov/products/predictions/610day/500mb.php http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=101&map=0&type=0&archive=0
  16. 7 points
    Afternoon Some quite varied interpretations of the model output so I thought I’d summarise my interpretation of the output in the simplest way I can to aid new members. A few days ago I mentioned the possibility of a split in the polar vortex from the high pressure cell over NW Canada. Indeed that now looks to be happening with this synoptic picture at T96. The PV is split like a knife through hot butter. Now this is no guarantee of a sustained cold spell over our part of the world, indeed it depends on whether the blocking can sustain itself and where the lobes of the polar vortex fall. Here is the synoptic picture another 2 days later, unfortunately two things go wrong: - Although pressure is encouraged to build over Greenland, the mild air doesn’t reach this area. It is a cold based high and therefore pressure only really builds over Greenland. - The cold shot of air heading into Canada moves ESE instead of S due to the high pressure sinking to the south-east USA. As a result, the lobe of the polar vortex over Russia moves into the arctic and the Atlantic fires up due to the cold air leaving NE Canada. The result is that the vortex is fusing back together and our chance to build some good northern blocking in our part of the world is gone. Where does this leave our longer term prospects? Well the Atlantic will probably be quite active due to all that cold air over the NE of Canada spilling out into the ocean, so it may be a little while till we get another blocked pattern. I wouldn’t get too despondent though unless we start seeing height rises to our south and south east. A possibility but quite a few ensemble members don’t build heights there. With that in mind we may get transient northerlies or ridges of high pressure coming in. Something may pop up at short notice. So fingers crossed we don’t get the height rises to our immediate S/SE, no white flag waving from me yet. December 2015 this is not, it ain't ideal but that’s the British climate for you!
  17. 7 points
    I would say large parts of the UK have snow next week on many of the runs including the most recent GFS 06z
  18. 7 points
    Barring a few GEFS which survive the zonal onslaught the SS Save Christmas has now sent out an SOS! The surface temps though dont look that mild , looking at De Bilt and given the set up which would mean northern parts of the UK would be colder there still could be some snow during Christmas week. There are still differences in the medium term between the big 3 with how low pressure exits the ne USA and the speed of that . So not great this morning but the jet still remains on a more southerly track upto T240 hrs and there’s always a chance of a surprise with that.
  19. 7 points
    Today Not much change from yesterday with the high pressure remaining to the south much of England and Wales and N. Ireland will be mild and murky with the odd spot of rain in the latter and one or two other places in the north. Much brighter in Scotland. Tomorrow a similar picture except light rain may well encroach western coastal areas. By 12 Saturday the high cell is coming under pressure from the east bound energy and a shallow wave depression is just north of Scotland with the front trailing away to the south west and rain already affecting the west coast of Scotland. Further south a brisk westerly is in place but still dry and mild. Over the next 48 hours the front and rain move slowly south as far as N. Ireland and the north of England but to the west it is still under pressure from the eastbound energy and by 12 Xmas Day is orientated over Ireland and a wave has formed on it and popped north east to be over southern Scotland. This could well produce some snow in central and northern Scotland. All the while England and Wales remaining dry in the brisk, quite mild, westerly which gradually backs.south westerly. This really heralds the start of a much more unsettled period as the front and rain traverse the the UK overnight, there could well be some more snow in Scotland and perhaps northern hills, before clearing the south east early Tuesday. But this is a very brief respite as the next low tracks quickly in from the NNW on a very strong low level jet and is 987mb over the Midlands by 1800 bringing a fair bit of rain the the south. Once more perhaps some snow on the northern edge of the front but best left to nearer the time. The low quickly moves away to the east but meanwhile another intense depression in mid Atlantic has undergone explosive cyclogenesis courtesy of 160kt jet and is situated north west of Ireland with associated front just encroaching the south west by 06 on Wednesday. Fortunately the low is filling by this stage but it tracks into the Irish Sea during the day and this could bring severe gales the the SW and Wales and perhaps a fair amount of snow in Scotland The low quickly moves east initiating a transient cool northerly flow over the UK but out in the Atlantic the 'bombing' scenario is being repeated, albeit the low taking a different track, and by Friday more fronts are approaching the south west. The GEFS anomaly this morning is not adverse to this scenario.
  20. 7 points
    I have to say, HC, that I read Ruzzi’s post as purely about challenging people to be inclusive in their MO discussion, not with any sense of there being anti-English content. In years gone by I used to post on TWO but one of the reasons I moved over here to this thread was simply that there was more local input about the weather where I live (and of course the banter is of a high quality ). This thread is inclusive, it’s friendly and it’s not too precious about the weather. Other aspects of life (politics, religion, etc.) are bound to come out in conversation now and again but I think the contributors to this thread do an admirable job of keeping it light, informative and entertaining....while still stamping their personality on their posts. Since it’s the season of goodwill, I’d like to thank you people for making this thread such a good read.
  21. 6 points
    Lots of negativity this morning. It’s not a poor outlook it’s just average IMO. Not sure how anyone can say it’s a poor for the next 10-15 days if you like wintry weather. Large parts of the UK will see snow next week, perhaps some are being very IMBY ?
  22. 6 points
    Those 10 hPa zonal mean charts are very sensitive to the movement of the vortex at the moment - the big rise occurs as it drifts across the pole having been displaced for some time; there's little or no strengthening of the circulation itself being indicated. Only longer-range hints from GFS of further stratospheric warming of any note to come though. How much and how soon varies with reach run depending on how the Arctic blocking aligns itself and to what extent it connects with mid-high latitude features. Seemingly a bit of a jackpot situation there. Somehow posted this early when pressing 'enter'? That's not normal! Here we can see the observed atmospheric state still edging toward the transitory state that could lead onto a renewed rise, but also clearly evident is the point at which GEFS decays out the Pacific MJO activity and the atmospheric state snaps back into a La Nina-like state. Shows just how close we've come; it would not have taken a lot more MJO amplification or duration to achieve the upward kick scenario with downstream amplification in useful places for us. It has been tense to watch us come closer and closer, only now reaching a point where a shortfall looks the more likely outcome. The subsequent IO emergence of convective activity is probably being overdone by GEFS though, hence the GLAAM drop as well, so beyond a week's range I'm inclined to treat it's output with even more suspicion that usual. Best chance we have later next week and a bit beyond is if the stratospheric forcing can tone down the westerlies sufficiently for the jet to dig further S into Europe, but the modelling currently favours this to happen in the middle of the N. Atlantic, which has the opposite effect on temperatures to what is desired by most on here. After that, we're back to trying to modify the pattern toward allowing a well-placed Scandi high, as GP has been alluding to as the best bet for good results next month. Unless, that is, a major stratospheric warming comes about after all.
  23. 6 points
    Noooooooo Fundamental points of model discussion Not even 1/3rd of the way through winter so all to play for More runs need More amplification needed GFS trending cold will do so again and ECM will come on board. If it doesn't its a crap model Look to T240 for things of beauty but they never verify of course Never look out of the window keep your eyes down for GFS12z and GFS 18z In May a full easterly will come along
  24. 6 points
    Its coming ' i tell you not ' its coming ... I feel it and i smell it ' after the 27th of this Month its going to get COLD i tell yah i tell yah ' you never Listen though ' i feel it in me bones and i am 78 and still smoke a splifter . Have a spliffy Crimbo to you all x
  25. 6 points
    We only have to look roughly 5 days back when folk were on the cusp of putting out the white flag. Euro slug appeared to be in full control things have changed considerably. Cumbria can do quite well away with these set ups away from the coast inland with some good elevation. GEFS shows lows taking a more southerly track this is a good thing to see, we need further corrections for more than usual suspects to see some wintry weather. Half baked? Nothing is in the flaming oven yet. D16 GEFS mean definitely looks wintry for Scotland. I’d be quite happy if I was up there!
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