Snowaddict

Not necessarily the coldest clark3r but in terms of hemispheric patterns, UKMO is stunning in my opinion, with cold air getting into the SE from T+120 and across the UK by T+144.

UKMO Model is really proving itself to be by far the most consistent. This has the potential to be the best cold incursion, synoptically speaking in 20+ YEARS. FANTASTIC 12Z UKMO!!!!! <_<

GEM 12Z has 850's of -5 heading into the southeast corner at T+114.. Can't see past T+120 on Meteociel but definite retrogression taking place... Shortwave due north looks to be sliding down into Scandi eventually but that's not very certain up to T+120.. Anyone with the link out to T+144?

12Z GEFS Suite: Excellent Control Run with a significant easterly by T+168 (Building blocks established firmly at T+132-T+144) Rock solid support for an easterly/northeasterly evolution with a significant area of positive height anomolies cented to the far northwest of the British Isles.

Out to T+132, the 12Z GEFS Mean has the western flank of the main HP cell being advected into Greenland, with heights falling over Scandinavia. By T+144, there is a mean easterly/northeasterly flow setting in over the British Isles. Even if they are not great after this point, up to T+144, the mean ensemble agreement is excellent on the 12Z suite.

The main thing is that the Easterly evolution is maintained solidly on the 12Z GFS Operational run this afternoon. Parallel run is much more consistent in relation to the evolution, with that perfect heart shape at T+150 and widespread uppers of -5 across the UK: http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=150&mode=0&runpara=1 The evolution is far from finalised and there will be many, many ups and downs yet, but the idea of cold or very cold weather developing over the next week, even less, is fast becoming a solid one.

Hi Tamara & thanks for the welcome back Some of the latest NWP output is indeed spectacular! It certainly is a very interesting setup. The cynicism amongst all is very understandable because of the amount of times that such cold spells have vanished in the space of one suite of runs. However, as you say, the background signals overwhelmingly support the evolution on this occasion. Fingers crossed that any shortwaves that do develop don't hinder but instead aid the advection of the cold towards us! I think that there may be multiple opportunities for cold incursions if the evolution becomes established correctly.

18Z Ensembles: Control Run brings 850's of -5 into the SE at T+138 Another excellent ensemble mean out to T+168, with mean pressure of 1020mb - 1025mb over Iceland and cold air filtering into eastern districts. All in all, quite simply excellent but everything is still far from resolved, so caution to be strongly advised.

Obviously there are still major hurdles to be overcome, but the idea of Cold arriving, be it inversion related or true cold is now pretty much guaranteed - the vast uncertainty relates to the potency of the cold etc. However, if it was to evolve as shown on the 18Z Parallel, there would be dangerous amounts of snowfall from T+192, witht that trough moving down from Scandi. Given that we are approaching the period of the year with the least amount of daylight, any snow could persist for quite some time & serious cold could be the result. All hypothetical as of yet but it's certainly trending in the right direction. I think that if we can get enough warm upper air due north and then cut off, then there will be almost inevitably a blocking scenario with significant cold. No doubt there will be many more ups and downs

Parallel Run out to T+150 - Simply excellent, 850's of -5 covering a large portion of the UK...

As others have said, a slightly slower, more 'flabby' evolution on the 18Z to T+144. But when you look at the amount of blocking there at T+144, it quite simply is wonderful given what we have had to contend with during Decembers of recent winters. Also, maxima really dropping off by next Sunday, down to 4C or less widely across the UK. As Ian Brown has said, with colder air filtering into the continent, lower heights are inevitably going to be established. An increasingly cold, potentially wintry, easterly to northeasterly flow is definitely the favoured evolution at the moment. It's going to be turning much colder over the next 7 days, even with the outside chance of some wintry precip to close the Copenhagen summit

What an interesting period in model watching! Around this time last year, perhaps a little later, we once again had great hype and excitement with regard to wonderful model output. Some might say that it's no different this time round & that's true in the context that any specifics beyond T+120 should be taken very lightly. Broad trends are alright up to T+144 & on some occasions up to T+168. This year is certainly different in terms of the intensity (or lack of intensity) of the polar vortex over Greenland, it's usual home in so many of the recent winters, helped by a to date, warmer than average temperature at the 30mb level: http://ds.data.jma.g...e/pole30_n.html Broadly tonight, all major model guidance is pointing towards cold, perhaps significant cold over the course of the next 7 - 10 days. Specifics will change, it may be that we end up with a stationery high over the British Isles, perhaps centred over Eire, or we may get that long awaited significant, real cold blast that is so well deserved by many faithful model watchers on here! From looking at all of the latest guidance I think it's certain now, greater than 90% that after initially being mild, conditions will cool down significantly in the next 7 days. Thereafter, we still don't know but the idea of cold to very cold upper air encroaching upon at least the eastern part of the UK over the next ~ 10 days is certainly gaining momentum, I would rate it at a solid 50% chance at the moment. Watch out for changes towards the T+96 - T+144 timeframe, those are the most important. We are by no means fully there yet but things are looking quite good. Also, just to add a ramp here's the ECM 850mb Temps from this evening - Steve M called it fairly right: -15's into the E at T+216, -15's widely across the UK at T+228: T+216 & T+228 Here's to an impending, increasingly bitter cold spell, with the potential for eventual snowfall occuring at a time when the power of the sun will be at it's minimum

Good Evening Eugene, It was myself who was posting about long term prospects on TWO after another poster had remarked about the re-appearance of the 528dam pool to the far north in the extended range guidance. As to it being far too early to discuss prospects for Winter 2009/2010, I simply don't agree with that & the UKMO will be issuing their NAO index outlook for Winter 2009/10 very shortly. I don't know the exact date, but perhaps JH could help on this? Anyway, whilst I do like wintry weather I also recognise output for what it's for when it occurs. Whilst there is no mistaking the fact that the coming 5 - 7 days at least won't be near as warm as it has been recently, conditions are not going to be horrific or anything like it. As an upper ridge approaches from the west into Wednesday and Thursday, conditions will likely become fairly pleasant, especially further south across the UK, with maxima still possibly reaching 20C. I'm sure that a return to less humid fresher conditions is a welcomed prospect by those who suffer from respiratory difficulties or who simply don't like the exceptionally warm and humid conditions that have been experienced recently. To put it nicely, you endeavour to always portray the worst possible slant on the outlook available given that it is currently summer. It's all down to personal opinion as to how the outlook is shaping up. For example, there were several t-storms over Ireland today, although it was much fresher than recently. Now many people may not have liked the cooler conditions, but several would have liked the t-storms (within reason and observing safety) & therefore that would not have been a bad outlook to them or anything of the sort. The point I am trying to make is that your posting recently seems to be wholly subjective and not reflective of the general guidance available. You distort the longevity of any settled or warmer patterns and seem to always take a negative slant upon the outlook. For example, 850mb temps will increase towards the coming weekend & whilst it certainly won't be completely settled by any means, conditions will become somewhat warmer once more, possibly rather more humid again. So please take a more objective approach when posting Eugene as it would be very helpful to many members. SA

Hi Tamara These are certainly some factors that I had not considered, so it would seem that there is some potential for a repeat of the neutral to negative NAO signature that we saw on various occasions over the past winter. My main concern would surround the strength of the upcoming expected El Nino cycle, but then again there is also strong correlation between this phase & high latitude blocking later into the Northern Hemisphere winter. Overall, I think regardless of other signals, the 30mb temperature has a huge bearing on developments, so that will be very important heading into Winter 2009/2010. As you say, the Met's intiial thoughts are eagerly awaited and should be very interesting. SA .....In repsonse to your latest post Ian, whilst you do have some limited validity in some of the points you make, your posting is overcome with the even larger teapot agenda, it's most unfortunate really. You mention a stroke of luck towards, to be honest that's a load of rubbish. A significant Midwinter Warming of the 30mb temperature at 90N, a split vortex and the correlating trospoheric patterns were a stroke of good luck, you have to be having a laugh mate. Such warmings are typical of some of the classic wintry incursions. Also, with regard to your outlook for coming winters & stating that it will be most exceptional if we get another Winter like 2008/2009 - My simple answer is that it is always so easy to back the most the likely outcome, risk equations would have you in front, but I think the underdog deserves a chance here. To contrast your own opinion, IMO a severe wintry incursion, more significant than February 2009 will develop during the course of the next 1-5 years across the British Isles & will be typical of severe wintry incursions during classic winters of the past.

Absolutely well said Kevin. That's precisely the essence of the problem as I noted earlier. Ian, you need to adopt a far less insular approach when looking at the overall trends and not always with the even larger teapot logic as that simply just won't work, as you noted last winter. Also, this may help you in the publishing of your book if you adopt a more objective approach.

The eventual reply is certainly a positive. When you say you lead the way, I don't really understand this, in terms of your statement with regard to determining the persistence of a northerly tracking jet, as this trend has been quite plain to the observer when it has occured. With reference to High pressure at northern latitudes in summer and poor resultant patterns, it's not really that simple. Take for example the coming week - we have a very -AO signature correlating with blocking at 60N - 65N (High Latitudes) and further north to our northeast. Now this will result in a rather to very pleasant mid summer pattern for the majority of districts, therefore the amount of positive correlation between the aforementioned pattern and poor summers is not a set and fast one, to put it briefly. Do you have any idea at present when publishing of your book will take place? SA :lol:

Why are you ignoring the posts which question your hypothesis Ian? Could you kindly explain to everyone here the most recent developments that you have made with regard to the even larger teapot theory as there must be many when you are writing a book on the topic. Also, fact is, no matter what way you alter it, last winter had minimal aspects of the so-called even larger teapot & sustained cold was achieved even without extreme high latitude blocking. I think you must get things into perspective too and constant drumming on about the same old story in spite of the most recent trends does become tiresome. Let me make one thing clear though, I am not completely disproving your theory & as ever all people's concepts should be given air time, but you are going to make yourself far more prone to error when adopting such an insular approach as that of the even larger teapot. You don't even consider other background factors or possibilities & that's your point of conflict & peril. From your latest comments anyway I assume that you are expecting Winter 2009/2010 to be a very even larger teapot :lol:

Interesting Ian that you should mention teleconnections because no matter what the pattern driver, be it El Nino, La Nina etc, blocking at 60N and further north will always be heavily dependant upon the state of the stratosphere. You state that ''we have to put the pattern down to a Hale winter''. To be frank, we have to put the pattern at the start of February down to a warming of the stratosphere. Similarly, we must take into account the 30mb temperature just prior to Xmas and from there out. Furthermore, where does your hypothesis factor in the marked increase in anticyclonicity that I have already mentioned along with the drastic decrease in the westerly flow over the past 6-8 months. You continue to be blinded to your detriment with you christmas pudding stance & no doubt that you will plague weather fora with it if a Bartlett High or a very mild southwesterly flow is to set up during the coming winter with the mention of the now infamous blowtorch. I recall statements from you during the past winter stating that ''It won't happen because this is a even larger teapot''. Fact is that lower heights on the continent were not responsible for the very cold Feb 2009 incursion, high latitude blocking to our northeast was responsible - brought about by the SSW. It's only June & you have already started the even larger teapot Agenda. I'm interested to know have you published a paper on this even larger teapot? Certainly if you put 1/10 of the time into such a paper rather than the attempts to stoke up tension you might make some headway, but then will any headway be ever possible on such a paper that is based on an approach that does not encompass all signals and factors. At this point, the same old stance from you is getting rather tiresome :lol: Why not just try and be more objective!

Ian, what a load of absolute rubbish from someone who is capable of much better. You are completely blinded by your christmas pudding ramping that never ceases to feature in every aspect of your posting. Of course you would look at it as the mildest Hale Winter ever recorded because you are simply obsessed with the so called christmas pudding. You are simply addicted to the term & concept of the even larger teapot & this has diminished your ability to post objectively. Last January was supposed to be a ''blowtorch January'' over here in Ireland according to your own forecast, yet even with a flattish zonal westerly flowed several areas only managed daytime maxima of 4.5C & 5C with harsh night frosts. You stated before the easterly flow in February that the predicted easterly was a ''red herring'' & that it would be in no way significant. In excess of 30cm of snow in 24 Hours in Leatherhead with 5-7 Days of lying snow here in Ireland is certainly significant. What you are hoping for is that a very agressive El Nino pattern sets up as we head into Winter 2009/2010 along with a strong +NAO signature & assoicated positive height anomolies to our variable south & resultant SW'ly flows so that you can once again proclaim the even larger teapot / christmas pudding stance. It's no surprise to me that you have now begun to post once more on here as the very earliest signals for Winter 2009/2010 would point to an overall average or above average CET for the period. That does not preclude however the possibility of an increased bias towards Blocking along 60N - 70N & assoicated NE'ly - E'ly flows as has been the case quite frequently for the past few months along with the sharp increase in anticyclonicity. There's a certin Corbynesque aspect to your posting, where you distort the facts to support your own agenda. Hopefully that going forward you can cease being blinded by such an agenda and begin to post objectively once more. I remain doubtful however.

That's great to hear C Thank you very much for posting up the info. Regards, SA B)

At present I think there is certainly some credence to this idea Mushy, particularly with reference to the Southeast UK. Whilst I know that anything past T+120 is subject to significant change - with the latest ECMWF operational output in mind - where do we find to be the most settled region into FI? - The southeast of the UK. This is clearly hinted at once again in the latest medium term UKMO update. Perhaps if there were consecutive thundery outbreaks then it may alleviate the situation, however this is not showing at present. Furthermore, without doubt these potential drought conditions are a direct by-product of the marked increase in anticyclonicity over the past 6 - 9 months or so. Before this, we had one area of low pressure after another steamrolling across the British Isles. At present, that pattern has come to a hault. So if there was to be a further persistence of high pressure then yes I think that water shortages at least could become an issue into the summer, but that's a while away yet. Does anybody have any of the water levels in terms of % from reservoirs in the southeast UK? Regards, SA B)

Those are absolutely stunning pictures Yeti, simply fantasitc You captured the surrounding landscape really really well, with a fantastic weather backdrop. It's great to see nature at work - the mother protecting her lamb, amongst fantastic scenery. The pictures from inside the caves are great also, I can imagine it must have been a bit tedious taking some of them. The photos taken over Ribblesdale are also fantastic and show up the scarred landscape very well. You have put a lot of time into all of those and thanks a million for sharing the photos from what is certainly a beautiful stetch of countryside. Best Regards, Mark.

Rather far away, although high thin layers could remain in place overnight. Towards dawn, cloud should begin to spill in from the Atlantic seaboard with drizzle encroaching from the west in places into tomorrow, coupled with a rise in temps.

All of the showery activity has now finished over Ireland FrostyJoe. Winds are becoming slack, with frost formation widely. Regards, SA.

Fantastic shots Sillkalven. Thank you very much for sharing them with us. It's great to see such wintryness still well established into March, even with the higher angle of the sun now. Many thanks again. Regards, Mark.