stodge

http://modeles.meteociel.fr/modeles/gfs/runs/2014012906/gfs-0-78.png?6 A very threatening storm for Saturday with especially strong winds to the south of the storm centre which of course doesn't cross the country but curves NE and then NW. http://modeles.meteociel.fr/modeles/gfs/runs/2014012906/gfs-0-156.png?6 Any number of (I suspect) very difficult to forecast secondary features to enhance the wind and rain especially (but not exclusively) for the south so another pounding (or series of poundings). The furthest reaches of FI offer some form of respite as the core of the vortex pulls westwards over northern Canada and pressure falls over the Bering Strait http://modeles.meteociel.fr/modeles/gfs/runs/2014012906/gfsnh-0-384.png?6 Far too early to write off mid-February and onward at this stage. We knew there was like to be a final fortnight of Atlantic-dominated weather starting about now and we are just perhaps starting to see hints as to what might follow.

On the other hand, the stratosphere won't stay this cold forever - we know this. Whatever may be showing tentatively for early February, it's a pretty safe bet that warming will happen at some point. For those hoping for snow, even late March or April can deliver so far too early to be dismissing such prospects. I've seen some forecasters offering HLB in March but the stratosphere is going to stay this cold right through February that seems improbable at this time Tamara offered the thought the day before yesterday that when the warming does occur, it could be very rapid and very dramatic - do we have any evidence from past winters with such cold stratospheric values that warming is more rapid - it would seem a reasonable premise but I've no evidence.

Morning all A rare opportunity for me to glance at the morning output (especially as getting up at 5am doesn't appeal). To be honest, it's all been said. GEM looks the wettest of a soggy bunch with UKMO perhaps the driest overall. The storm for the coming weekend still looks thoroughly unpleasant and no doubt continues to cause significant concern at Exeter and elsewhere though oddly enough UKMO is perhaps the least threatening of the model variations in terms of approach and intensity. I'm less convinced about the warmer evolution this morning as well - again ifs and maybes for the extreme south but not much to be honest. I note the earlier comment about the Iceland HP for March - it ties in with a number of thoughts I've seen for a post-winter evolution.

Well, he's not alone - the Danish Weather Service (DMI) in their latest monthly update have argued for a mild first half to February, a colder second half and a strong signal for HP to become established "to the west of Scandinavia" (their words translated) in March. Now, I concede cheerfully that may be wrong and it may not help those who want cold in the UK - the suggestions are either a NW'ly flow for Denmark (which would suggest an HP close to or over the British Isles) or a N'ly flow (which would suggest a higher latitude block). I think the next pattern change won't be to a snow-lovers paradise (I fear that ship has sailed for the snowies) but it will be to a more anticyclonic scenario which might be colder or it might be much warmer.

Morning all Extraordinarily downbeat mood this morning on the basis (it seems) of one set of Operational output and a Strat not shattering into fragments on request. Please remember that we are only going out as far as mid-Feb even now and it's extraordinary that after routinely castigating every forecast he has ever made, somebody has just quoted a Piers Corbyn forecast as though it were the unvarnished truth. If we don't get any snow this winter, so be it. I'm a long way from throwing in any metaphorical towel as I never thought anything much would happen before mid-February. It might do some people on here a bit of good to step back from over-analysing every scrap of output for a few days and come back with some renewed perspective. As I said on the Winter Discussion thread yesterday, many winters have had March snowfall after a mild core period and it can even snow in April under the right conditions. I do think blocking will become the key player from the middle of February onward but I don't know it will be cold or mild (Corbyn's theory presumably). My gut feeling says it may be akin to March 2013 with the block just to the north or north-west of the British Isles - too close for snow but able to feed in a much colder flow. To assume on the basis of one or two set of outputs that it's going to be a warm February and to support that theory with the forecasts from a widely-derided pundit seems absurd in the extreme. Tamara has said many times the stratospheric vortex will have one more period of dominance before it weakens finally and we are moving into that period at the end of the week. That period will last at least a fortnight but I don't know what will happen after yet but it will be different to what we have seen since early December - will it be a late winter or an early spring is the real question.

Evening all A rare opportunity to post my weather thoughts and I thought I would eschew the Model Discussion bear pit and the Moans, Whingers and Grumblers in their forum and come here if that's ok. It's been by many measures a remarkable winter period so far - one of the longest periods of sustained unsettled weather since the Autumn of 2000 with copious rainfall after a preceding (and seemingly forgotten) very dry and mild November. Yesterday's thunder storm would have graced any breakdown to a Spanish plume for intensity and it's not been the only intense squall. Contrary to some on here, my area of lowland East London has had a few frosts and even a little fog (though once again another quiet year for this phenomenon which definitely seems to be less prevalent than 20-30 years ago). I thought we might have an anticyclonic midwinter and apart from the first four letters, I was spot on !! The indicators for an unsettled winter were there from the start with an extremely cold stratosphere setting up in early December, overpowering the long-standing European HP block and ushering in this long period of stormy and wet conditions but many credible LRFs (as distinct from hope casting) expected this and also argued for a much weaker stratosphere from February onwards. This seems to be what is happening or about to happen and the stratospheric profile for mid-February looks very different. That said, and as the superb Tamara has opined on more than one occasion, breaking such a powerful vortex is a long job and so it has proved and even now it has enough power to hold the line into the start of February. I had hoped we might be a little further forward but it now seems likely that the first half of February will be the swansong of the vortex but what follows ? A late spell of winter or an early spell of spring ? That brings me to the usual old piffle from contributors to the Model Discussion Forum whining on ad nauseam about it being "too late" for snow in late February or March. Now, when I cast my mind back to the last year it snowed in March - oh yes, 2013, so long ago. If the air is cold enough, it can easily snow in March. My concern re: settling snow would be the warm ground but that could be cooled quickly under the right conditions. In my part of the world, ALL snow is transitory - the falls of 1st February 2009, 18th December 2010 and 19th January 2013 were all good to look at but, apart from the 2010 fall, most of it went within 72 hours. The urban heat island that is London takes a quick toll of settled snow but that doesn't mean snow can't fall even in what would normally be called spring. We've had snow in late March and even once in April so it's far from game over for snowfall. If the only thing that floats your boat is weeks of lying snow and cold temperatures than go to Canada or Siberia and you'll be happy. We may not get much out of the next few days (or we may) but I'm far from downcast for mid-February onwards. I do think the prolonged period of prolonged rain will end . We MIGHT get a prolonged period of cold with snow - we MIGHT get an early spring with warmth, I don't know. My money (and nice money it is too) would be on something cold for the second half of February and into early March before a rapid shift to a warm early spring spell but I've been generally wrong so far about this winter. I do expect a final period of Atlantic-driven weather into early February and will be looking at the distant reaches of FI from the end of next week for the beginning of the next chapter.

http://www.dmi.dk/vejr/til-lands/landsudsigten/ A straw of sorts for the coldies - yesterday, the Danish Weather Service (DMI) were calling for milder weather to spread across Denmark over the weekend. Not so today, the "cold from the east is winning this round of the battle" to offer a translation of the title. The HP over Finland is, according to DMI, going nowhere and keeping the milder air to the south and southwest of Denmark. Now, that may well mean the UK but that is a significant change in its 3-5 day forecast from yesterday to today suggesting to this observer that the "battle lines" are further west and south west than expected at this time yesterday.

Thanks for the good wishes, my friend, and you'd be happy with some of tonight's Model Output particularly GEM. I've never been confident about this winter - too many indicators were pointing the wrong way for the coldies from an early stage. Even the stratosphere may not "rescue" us this time with an SSW though I do think the vortex will be weakened through the rest of this month and into February. Come March and I do think things could get very interesting - 2013 will tell you that it's perfectly possible to have snow in March. The Danes are talking up the idea of northern blocking and with a shattered vortex, there are possibilities but no more.

Afternoon all As it's my birthday and I've had the day off, I've also had an opportunity on where we are at the halfway point of winter and where we might be going: I'm 53 years old today - Happy Birthday to me, Happy Birthday to me, etc. etc. - and the number of years with snow on the ground on my birthday I can count on the fingers of one hand. The weather on my birthday can be split into three types - mild and wet (as today), mild and dry or cold and dry. I would say mild and wet at 60%, mild and dry at 25% and cold and dry at 15% sums it up. For all that it is midwinter, most Januarys do not deliver for cold and snow - the stratosphere is at its coldest in many of these years while in others the synoptics don't fall right to provide snow for lowland southern England, which is in most instances pretty marginal anyway, Those who think after the latest four or five winters that it's going to suddenly be different have had a rude awakening this year. All the signs for a mild winter were there and most sensible LRFs suggested that would be the case. Indeed, I'm tempted to think going forward that one of the signs of climate change is or may be colder stratospheres and lower levels of stratospheric ozone so what we have now is more likely to be a precursor for the future than a return to colder and snowier winter conditions (which will still happen though less frequently). What then for the rest of Winter 2013-14 ? I never expected anything before late January but had hopes for February. While I note the encouraging comments from a number of experts re the stratosphere, the truth at the moment is that the forecasts of a split vortex by month end look dubious at best. To me, it looks as though mid or even later February may see our first prolonged period of non-Atlantic weather but even that is starting to look optimistic. The recent UKMET outlook was uninspiring for coldies and the Danes are in similar vein: http://www.dmi.dk/vejr/til-lands/maaned-og-saeson/ If you read this with the translator (or without if you're like me) then the line is that February in Denmark is going to be mild and wet with temperatures between 3-6c all day so little if any frost. The interest starts with the second paragraph which re-states the milder than usual forecast for February but then states that in March and April there is a higher probability for High Pressure to become established "west of Scandinavia". Now, the Danes talk about a NW'ly or N'ly airstream resulting but that wouldn't need much alteration to mean a more pronounced northern blocking scenario which would tie down with some of the more optimistic stratospheric forecasts. I'm left then with the thought that early February will continue Atlantic-dominated with rain at times and milder conditions before we see blocking from mid and late February become established perhaps close to or possibly to the north of the British Isles. March 2014 may not be an exact repeat of March 2013 but I do think there's a lot of reasons to think it could be very blocked and possibly very cold - my money (and very nice money it is too) is on NE or E'ly winds but providing more in the way of dry and cold than outright snowy conditions. What I am increasingly coming to suspect is that for many on the forum the pain of a mild winter will be exacerbated by a thoroughly cold spring at least initially.

Morning all Well, I've been trying to get my head round this topic and found this interesting paper from 2009: http://www.acd.ucar.edu/Research/Highlight/stratosphere.shtml This and other papers seem to set out what could be the basic theory - the stratosphere has been cooling (though not as a uniform process) since the late 1970s which would coincide with the end of the cooling period from the 1940s which some ascribe to the influence of sulphur dioxide. A cooling stratosphere would be caused by rising levels of carbon dioxide and falling levels of stratospheric ozone. That would suggest that as the world warms (if that's what is happening) one of the consequences of increased CO2 would be to cool the stratosphere. We can therefore posit that at times of very low CO2 (ice ages) the stratosphere was much warmer and therefore northern European winters were much colder and more blocked. Conversely at times of higher CO2 (dinosaurs), the stratosphere must have been much cooler and winters so much milder. Indeed, I believe having two polar ice caps is a rarity in Earth's climatic history. I would love to be able to prove this correlation conclusively and suspect there are other factors at work. CO2 levels are rising but we've also had cold winters with a warm stratosphere so there must be other things going on. Some cite solar activity which must play a part - I believe the LIA coincided with a period of very low solar activity - could that in turn have helped maintain stratospheric ozone levels and maintained a warmer stratosphere ? I don't know and all I have are a series of contradictory ideas.

Morning all http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-150.png?6 This is for me the critical moment of the current evolution as shown on the 06Z Operational. The lobe of HP over Finland which broke away from the main central Asian HP is set and established but the orientation isn't brilliant for us. That said, it's strong and supported by lower heights to the SE and SW. Pressure is rising over the UK as the trough dissipates but then: http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-162.png?6 Up pops a little feature in the North Sea and that's that. GEM this morning offered the possibility of a more anticyclonic evolution IF the trough fully dissipates and this is for me still an option. http://www.meteociel.fr/modeles/ecmwf/runs/2014011400/ECM1-168.GIF?14-12 ECM this morning got near to it as well but again not quite. It will be interesting to see how this plays out on the afternoon and evening output.

Indeed, back in the bad old days pre-2009, one of the "hopes" for a break from the seemingly-endless zonality was for the Azores HP to ridge NE and "link" with heights over NE Europe - not that it happened too often but it was one of the "hopes" for the coldies. The problem of course is that the ridging HP often left us in an anticyclonic col - cool but a long way from snow. Not a million miles away from this: http://www.meteociel.com/modeles/ecmwf/runs/2014011112/ECU1-240.GIF?11-0 Perhaps a wintry shower to the East or South East but not much else.

Morning all Another day, another set of ludicrous half thought-out one-liners filling the MOD thread. Some people really do stake their lives on the turn of a programme - there's the next generation of compulsive gamblers for you ! To be honest, I've quite enjoyed the milder weather - I have an early start and a long journey to work so I'll take dry followed by mild. I hate snow and ice as much as I hate wind and rain first thing on a winter morning. Looking ahead, the evolution beyond Sunday is far from clear and far from certain. I honestly thought we would have an anticyclonic winter but I was wrong about that - I've also been of the view that the coldest weather would be mid-February and I might be wrong about that too. I'm surprised how quickly this evolution has develped in the past 72 hours and, as the usual doom-mongers will no doubt relish in pointing out, "it could all go wrong". Honestly, there are some people who would scream downgrade if the storm force easterlies at T+6 were -15 uppers rather than -20 and no doubt the usual suspects will be going on about the breakdown before the cold spell has started.

First, Happy New Year to all model watchers. Some thoughts: - first, many many winters have been "late starters" and it's far from unusual for late January and February to be significantly colder than the period before. Indeed, the converse is true - a cold pre-Christmas often means a mild January and February. I despair at those who think we should have storm-force easterlies and -20 uppers on every chart and write off weeks at a time on the basis of a couple of poor Operational runs. Now, I'm NOT saying that we 're going to get something unexpected - we know so much more than we did in 1962-63 let alone 1947. It's entirely possible that had we known then what we know now we'd have seen the cold spell coming 5-6 days in advance. For example, we now know and can predict SSW events in a way we couldn't even a few years ago. I've never thought we could get a cold outbreak until late January and into February. IF the strat conditions are favourable, we may get something interesting but I live in lowland London - snow for me is marginal and transitory at best. The fall of December 2010 was mostly gone in a week - most snow generally doesn't last that long in the urban heat island. I'd be much more intersted in cold, frosty and foggy conditions which could provide some serious ice-days for my part of the world. Unfortunately, too nany people look at charts in isolation and don't even understand those to be honest. There is a "Technical" part to the MoD and I do wonder if the Martins of this world would be better off putting detailed analysis in there. An alternative would be to split comment on high-res and low-res output. Have one thread to discuss output from T+0 to T+144 - this is the high-res modelling which while liable to significant change itself is more generally reliable and verifiable. The Low-res thread could cover all later output and be open to those looking for trends and longer-term ideas for output. At the present, the MoD splits into three - a) those who want a particular type of weather and look for charts to back it up b) those who deal only in high-res output, are quite dismissive of the low-res and concentrate on short -term detailed forecasting directly based on the output and c) those who study high-res output to pick out trends in an attempt to offer longer-view forecasts. The prize is spotting the trend first and watching it move into low-res and verify with the sense that they spotted it first. To try and create some objective model-watching utopia where only skilled forecasters comment calmly on high-res output would be to create a sterile and ultimately boring forum. I can read charts as well as the next person and I'm much more interested in the output that isn't publicly available rather than all the output and Ensemble data which we can all read and analyse. I'd rather have a thread with strat charts, long-range forecasting and trend-spotting rather than either pointless hopecasting or sterile professional analysis. I welcome the pros such as Ian F who come on here and offer some insight from professional bodies though sometimes they miss the point that it's as much about spotting the trend than simply looking at the Ensembles which mask the outlier which becomes the trend. Looking at the Ensembles is like backing the favourite in a horse race - you'll probably win but backing the outsider and watching it win the race is more profitable and perhaps more fun.

Afternoon all Nothing teribly surprising in Ian's clarification. The output has taken several steps away from mid-month cold in the past 36 hours and even the previously-touted break from the prevailing cyclonic outlook is now looking less and less likely. None of this of course rules out colder conditions in the last third of January let alone February. Many UK winters have been "late starters" and even the poor winters of the late 90s and early 00s often had colder spells in mid and late February so even if you write off the next two weeks or so there's still half a winter left. I originally thought the winter was going to be very anticyclonic and that Christmas would see a lot of fog and frost so perhaps my prognostications aren't as reliable as Ian's but then I have my rabbit's foot and dice whereas the technology at Ian's disposal is slightly superior.

http://modeles.meteociel.fr/modeles/gfs/runs/2013122712/gfs-0-204.png?12 Afternoon all Not quite sure how that synoptically works to be honest. http://modeles.meteociel.fr/modeles/gfs/runs/2013122712/gfs-0-288.png?12?12 Well, it's nice to look at I suppose. http://modeles.meteociel.fr/modeles/gfs/runs/2013122712/gfs-0-372.png?12 Again, nice to look at - I suppose the one message I'd take from the GFS 12Z operational is that the sign for a southward migration of LP centres and a more NW/SE alignment is still there as is the sense of things slowing in the Atlantic.

Thank you for the response, my friend. It's something that is intriguing me and has done for some time. I'm trying to get my head round what a "typical" LIA or Ice Age winter would have looked like in the UK. Knowing what we know now about the climate and how it operates, I'm sure it would be possible to generate a climate model for the LIA and doubtless this has been done somewhere by someone. Of course, even in the LIA there would have been "milder" winters just not so many of them so it seems probable that some form of Atlantic dominance (powered by the stratosphere and the PV) must have existed even then albeit weaker and more sporadic. But then we're back to what makes a cold stratosphere - you'd think that in a colder world the stratosphere would be colder still and the PV stronger but the history suggests otherwise so perhaps the PV was larger but more disorganised (perhaps spreading over a much larger area of the NH) but somehow the troposphere was warmer (logical given the radiation/inversion effects, am I on to something here?) creating a feedback loop where the warm troposphere kept the stratosphere warm preventing the formation of a strong PV and encouraging more HLB leading to more radiation and inversion. It would require a strong boost from the Atlantic (what were the SSTs in the LIA?) to break the loop so the cold, dry winter would just drag on for weeks if not months and the summers would be characterised by more rain as the LPs took a more southerly track. How does this sound ?

Well, that may be true if you're travelling from the east, but if you want to head south or west out of London, forget it. In East Ham, slight damage to garden and garden fence but everything else looks ok so far. I can't get to work because of the aforementioned train problems. Oh dear, how sad, never mind

Hope the stratosphere/vortex experts don't mind me asking a couple of historic questions in here. 1) Has the PV always been around Greenland/Canada/Siberia ? I gather it tends in winter to be around 80-90N though could be anywhere within that area. That said, there seems to be a preponderance toward Greenland rather than say north of Scandinavia. I wonder where the PV was and what it looked like in the LIA or in the last Ice Age ? 2) Similar question re: stratosphere temps. We talk about a cold stratosphere in winter and I understand it's warmer in summer etc, etc but what were strat temperatures like during the LIA or the last Ice Age ? Historical accounts of winters in the LIA talk about cold and frost rather than snow which makes me think the prevailing synoptics were an easterly flow from HP over Scandinavia or to the North of the UK. That synoptic would suggest a warmer stratosphere and a much less vigorous PV but is there any scientific evidence for that assumption ? Presumably when the last Ice Age ended, there was a gradual (rapid in geological terms) re-distribution of the atmosphere from what prevailed in the colder epoch to the current interglacial but what triggered that - solar activity ?

Thanks very much for the responses. You've answered some of my questions but I'm going to follow the Bish's advice and take this into the Strat thread.

There's a lot of talk over in the Model Discussion Forum about the strength of the Polar Vortex and the impact of the temperature of the Stratosphere. Let me start with a confession that I'm more of a historian than someone interested in the weather but the two are connected in any number of ways. My first thought is to ask if the PV is often situated around or over Greenland ? Given its influence on the weather systems, you'd be forgiven for thinking it's been there for hundreds, if not thousands of years, but is that true ? The British winter is prevailingly temperate and that could be explained by the position and strength of the PV but it also seems connected to the stratosphere and its temperature profile. Does the Stratosphere go through cycles of warming/cooling in winter ? Is it warmer some years than others and if so why ? Back to the history, then. During the LIA, would it be fair to say the PV was weaker or differentally positioned to today ? The accounts of the period talk more about the intensity of the cold then the snow which suggests to me long periods of anticyclonic conditions with E'ly or SE'ly flows off Europe rather than snowfall. That in turn would suggest a weaker or disrupted PV perhaps over Siberia but why did this happen ? Going forward, it seems to me that a stronger PV is a logical outcome of a more energetic atmosphere but is that valid and would not the stratossphere be warmer as a result of changes in the troposphere ? I'm sorry - plenty of questions I know but I'm trying to understand how the weather might have worked in the past and its influence on our cultural and historical development.

Evening all The 18Z Operational output keeps the very stormy theme going over Christmas but this time it's the south in the firing line; http://modeles.meteociel.fr/modeles/gfs/runs/2013121618/gfs-0-204.png?18

Morning all A rare opportunity to comment on the morning's output and there's not a lot to be said which hasn't already been said by those who frequent the early hours. My observation is less related to wind (so to speak) than rain - seems very hard to tell but could we see secondary features developing along the cold fronts which would bring more in the way of rain (rather than the wind) to southern counties ? The current set up looks to offer plenty of potential for the rapid eastward clearance of frontal systems but a much slower southward progression - very hard as they might develop at short notice, but I do see the possibility of rainfall to the south from these not so much secondary LPs but "wave" formations along the cold front.

Evening all According to the Danish Weather Service, London is -2c at present so a frost setting in but as others have said, the fog has cleared. I presume we have now imported some drier air from the Continent. http://www.dmi.dk/vejr/ Great map for moving round Europe and looking at temps - London currently colder than most of northern and eastern Europe.

I remember a succession of frontal systems comin in from the SW and stopping in central Scotland before the whole lot rolled south withthe cold HP behind it on New Year's Eve - extraordinary. I'm a lot more positive than some on here this morning - GEM offers an alternative evolution (again) while the far reaches of GFS 06Z aren't too bad and the suggestion that the Sceuro HP may break down a bit quicker than seemed likely yesterday is starting to gain a little supprt. Again, as others have said, it's only the sixth day of the ninety day winter period and there's a huge amount of water (or ice) to pass under the bridge. Just 12 months ago, we had two or three very cold and frosty days in mid-December before a four-week spell of unremitting zonality with too much rain for many and then mild and dry conditions through New Year and even up to mid-January. Many of the LRFs I've seen for this winter have posited a classic "late" winter with February the favoured month for cold and snow so a 10-14 day severe event then will make the winter of 2013/14 memorable and all this will be forgotten (until the next zonal spell) and as I always say - "the route to very cold always starts from very mild"