Thundery wintry showers

I've stated recently that I'm not a big fan of the phrase, "rules are rules". Firstly, what does the phrase mean? It's often not entirely clear, but in general there are two main interpretations: Definition 1. "Rules must always be obeyed and infringements must always be punished" For example, [i]X is prohibited.[/i] [i]People who do X should therefore be punished for disobedience. If you allow people to get away with breaking rules you'll end up with anarchy.[/i] [i]If people want to have the prohibition on X removed, they should campaign to get the rules amended.[/i] One significant problem with the above is that when we campaign to get the rules amended, we often run up against the following "rules are rules" argument instead: Definition 2. "The rules should be the way they are because they're the way they are". For example, [i]X is prohibited.[/i] [i]People shouldn't do things that are prohibited.[/i] [i]Therefore, people shouldn't do X.[/i] [i]Therefore, X should be prohibited.[/i] [i]There is no good reason to relax the prohibition on X, because everyone knows what the rules say, and if everyone obeyed them, there wouldn't be a problem. If we relax the prohibition on X then we'll end up with anarchy as if you give people an inch they'll take a mile.[/i] Definition 2 amounts to a circular argument and is commonly used to prevent discussion on the correctness of a rule, the way it is interpreted and enforced, or whether or not it should have some discretionary flexibility. I am a particularly big opponent of Definition 2, but there are cases where I would support Definition 1. Rules are a [i]normative[/i] thing, where we set up codes of behaviour that are considered acceptable, but prohibit behaviour that we consider unacceptable. Up to a point, we do need such cast-iron rules to help discourage irresponsible behaviour, be it subjecting others to pain, gaining an unfair advantage in sporting competitions for example, and it is generally a bad idea in those situations to allow exceptions. However, because of the normative nature of rules, "rules are rules" is also a common argument for justifying ganging up against individuals or groups for being different (and is remarkably neglected in articles relating to bullying, racism and the like). A peer group can set up rules of conduct like, "be heterosexual or be ostracised", and then justify ostracising homosexuals on the basis, "their homosexuality violates our rules, the rules are the rules, and so homosexuals should be ostracised by us"- they see it as equivalent to, say, being fined for stealing from a shop. As far as the group is concerned, it doesn't matter what you or I think regarding homosexuality, what matters is that the group doesn't tolerate homosexuality, it sets up rules accordingly, and "rules are rules". Another point regards civil disobedience, in situations where people know that campaigning for the rules to be changed gets you nowhere. Was it right for the Jews to be executed by the Nazis for disobeying Nazi rules? An extreme case, but the point is clear. I won't deny that I am no stranger to what I consider "civil disobedience". This has often included, when being ostracised for being different to the norms of a peer group, refusing to change to fit in with their behaviour. It has also included disobeying rules that prohibit behaviour to legislate for a a minority who abuse it (as campaigning for change to such rules usually fails to get beyond the arguments "rules are rules" and "the majority have to spoil it for the majority"). The danger with attempting civil disobedience though is that you can inadvertently end up behaving irresponsibly, by recognising that a rule is over-restrictive but deviating from it too far. Overall, my objection to "rules are rules" is that morally speaking it only works (by definiton 1) if the rules are sound to begin with, and it is a way of preventing debate on the soundness of the rules.

Feb1991blizzard's question, "would you take a cold winter in return for a hot summer?" is interesting as while I generally regard that combination to be the best of both worlds, there may be exceptions in some of the most extreme cases. The general rule of thumb for prolonged snowy weather is that I enjoy it up until the point when repeated freeze-thaw cycles turn the snow into solid ice, and after that my enthusiasm drops markedly (not in the sense of getting fed up with cold/snow, but rather wanting a temporary thaw to remove the ice). In February 1946/47 a more significant problem would have been the acute shortage of sunshine and severe flooding around mid-March. I think on balance I would probably have enjoyed 1962/63 overall, with my enjoyment of the first half more than offsetting the second half dragging on a bit. I can't think of any hot summers from the past that I would consider unwelcome, though I must say that I'd probably rank 1976 below the likes of 1975, 1989, 1990, 1994, 1995, 1996 and 2006 due to relative lack of variety and notable weather events in the second half of the 1976 summer.

I agree, the models seem pretty strongly agreed on the change towards a changeable westerly type now. Although there is still some divergence among the model outputs, the general consensus is that the main rain belt will straddle most of the country tomorrow, from SW England up to SE Scotland, with only Ireland, NW Scotland and SE England missing the rain. It will be dull and wet for most early in the day, but the rain perhaps turning more showery late on, which could trigger some thundery activity over northern England tomorrow afternoon/evening. Over the weekend, a line south and east of Bristol to Hull will probably be generally sunny and hot over the weekend with highs between 27 and 31C. North and west of that line, the front will tend to fizzle out which may allow some milky sunshine through at times, and temperatures of 22-25C, and on Sunday the remains of the front may help to trigger some more thunderstorms over northern England and the north Midlands. Even most of Scotland and Northern Ireland look set to have temperatures into the low 20s, except for NE Scotland which will be affected by onshore winds (again!) Sunshine and showers looks likely to be the dominant theme on Monday and Tuesday, though with not many showers about on Monday, and not quite as hot in the SE but with temperatures in the low to mid 20s in many places. A breakdown, possibly thundery, is indicated by GFS on Tuesday night, which may be followed by sunshine and showers on Wednesday and possibly Thursday with temperatures falling close to average. After that, it looks like we'll feel the full force of the Atlantic again, with depressions coming in from the west replacing the showery regime with longer outbreaks of rain at times.

The problem with Laserguy's argument is that it assumes that Netweather.tv's membership consists primarily of weather enthusiasts. I think with many members "snow enthusiasts" would be a better description- there are many people who have a relatively limited interest in, and understanding of, meteorlogy as a whole, but are attracted to certain specific types of weather, and snow is the most popular of these. In general weather nuts, and this includes those whose livelihoods and hobbies depend on weather as well as enthusiasts, have pretty diverse needs and desires regarding the weather, but with enthusiasts tending to have a strongly above-average fascination with dramatic and/or unusual weather, which often includes snow, but also Spanish plumes, thunderstorms and the like. The majority of the population have a relatively limited interest in, and understanding of, the weather and are much easier to generalise in terms of preferences, i.e. the less inconvenience the better, although when considering this large group of people there is often a danger of generalising at the lowest common denominator, i.e. taking the minority who have absolutely zero appreciation of the weather and lumping the rest together with them. Similar equations exist for many other topic areas- you generally get a minority of hardcore enthusiasts, a minority who couldn't care less and a majority of casual viewers/users. Regarding the upcoming heat and precipitation, Sunday's precipitation charts are indicating the possibility of thunderstorms breaking out following a hot sunny afternoon over much of central and eastern England. It is easy to see precipitation charts and assume frontal type rain, but if the GFS verifies as shown then any rain will be hit and miss.

Philip Eden's stats for 1st-15th August, although the regional breakdown is not available yet: http://www.climate-uk.com/page2.html Slightly warmer, cloudier and wetter than average, with the rainfall totals boosted by the wet day yesterday, though I'm sure there will be regional variation on top of that. It certainly feels like it's been warmer and drier than usual here in North Yorkshire with sunshine no lower than average, although I think north-east Scotland has had rather cooler and duller weather relative to the rest of the country because of frequent onshore winds. The upcoming hot spell, meanwhile, is looking like it might be largely confined to East Anglia and south-east England although most other places should at least see temperatures rise above average, and the frontal system is likely to weaken by Sunday.

I agree with the last few posts- in these NW-SE split setups Manchester quite often gets at least some influence from the "SE" part of the divide. Merseyside sometimes does as well, but with less frequency due to being further west, while at the same time Merseyside stands a significantly greater chance than Cumbria and NW Lancashire. The same issue arises in winter, e.g. the 13th February 1998 (a classic case of a NW-SE split scenario where the dry sunny weather extended north-westwards for a time) had some sunshine at Manchester Airport and a high of 16.5C whereas at Lancaster it was grey and drizzly all day.

I vaguely remember being ill that week and watching an ITV forecast by Bob Johnson (a rare example of an ITV weather presenter that I regard highly) talking of cold weather with snow showers near the east coast during midweek, but "mild again by Friday". There were some snow showers in the Tyne and Wear area late on the 8th but they were hit and miss and the temperatures were marginal- Cleadon had just a couple of sleety flurries whereas nearby Sunderland had some heavy snow and a thin covering in parts of the city the next morning. Bob was certainly right about it turning mild by the 10th (Friday)- a belt of frontal rain was preceded by a bit of sleet and that was it! According to stats from Weather Log, northeast Scotland did manage a significant cold and snowy spell from this northerly outbreak, but many snow lovers further south would no doubt have been lamenting the fact that it could have been them too, if only the jet had stayed south. The notion of a heavy snowfall east and south of Glasgow on 17th February 1995 sounds quite plausible to me, as it was a very showery day (I actually remember it quite well, including being driven through some heavy ones in Yorkshire) and the showers were wintry on high ground, especially in the north. It must have been quite localised and/or restricted to high ground though as Glasgow Airport had no significant lying snow that month.

That's a I've seen the bit in bold suggested in the past, but it is inaccurate: continental areas generally have higher temperature variability. Over much of continental Europe, a summer heatwave will often produce temperatures above 30C and sometimes approaching 35C, and in exceptional cases, most notably August 2003, it may climb to 40C. On the other hand, away from the Mediterranean coast, maxima in the area of 15-18C are not unusual when frontal depressions take a southerly track and bring cool moist north-westerlies off the North Atlantic.

We've had many debates on how the UK clocks should be changed, but any changes that we make aren't going to alter the overall amount of daylight- removing problems with evening darkness creates extra problems with morning darkness and vice versa. Personally I find the onset of the dark nights quite depressing during the autumn months and that the dark nights drag on in January, although I don't mind December so much. Ideally I would prefer a daylight range like they get at about 40 degrees either side of the equator, from around 10 hours per day in midwinter to just over 14 in midsummer- this could mean 8am-6pm in midwinter, and then 7am-9pm in midsummer (allowing for BST). I recognise that this, too, would have downsides for a fair number of people, particularly for those who benefit from the daylight at 4-6am in a British summer, but from my personal perspective it would have very few minus points. I doubt that I would mind the advancing nights too much if I knew that even in the middle of January it would still be light at 5:30pm.

Not sure about Britain getting hit by the 20C 850hPa isotherm but a pretty serious heatwave looks highly likely over parts of France, with temperatures of 35-40C in the south-western third of the country during Friday and the weekend: http://www.wetterzentrale.de/pics/Rtavn12617.png France may even get visited briefly by the 25C isotherm. The weekend still looks like having a NW-SE split with a frontal boundary straddling a region of the British Isles- it currently is shown as straddling Wales and northern England on the GFS. Thus, depending on how the models shift over the coming days, it is unclear how widespread the UK heatwave will be, but barring a substantial south-eastward shift, 30C is looking likely near the south-eastern corner at present.

Looking over the model outputs, a weak front will be heading eastwards today: http://www.wetterzentrale.de/pics/brack0.gif A dull and wet start to the day in western and north-western areas, but some warm sunshine in central and eastern parts of England, bar some coastal fringes which have winds off the North Sea. As the day goes on, cloudier wetter weather will extend eastwards, weakening as it does so, and convective available potential energy is moderately high which could trigger some thundery activity at the frontal boundary. Tomorrow looks like being a day of sunshine and showers, and rather warm (highs of 22-25C over much of England) with the south-eastern third of England staying mostly dry, some thundery downpours likely in the west. Wednesday indeed may provide a lot of excitement for some as we very rarely get deep depressions combined with very warm, humid airmasses in this country- normally the warm humid air has already been heavily mixed out by the time the low approaches us (as is true with ex-tropical lows). Some ordinary frontal rain is likely on the warm front, but some warm humid air in the "warm sector" (temperatures of 22-24C likely) are progged to trigger some very heavy, thundery rain along the cold front. Thursday will see a return to sunshine and showers with the majority of the showers in the west, and perhaps a little less warm with some returning polar maritime air coming in. The GFS and ECMWF then both suggest a NW-SE split on Friday with Atlantic fronts giving cloudy wet conditions towards the NW, but a hot southerly flow bringing sunshine and increasingly high temperatures towards the SE- I'm sure the position of the three zones will be revised nearer the time. In my posts a while ago I made references to Julys 1994 and 1995, and I've seen some making references to early to mid August 2004. In essence, the synoptic pattern on those occasions was much the same, except that during Julys 1994 and 1995 everything was shifted further west (producing higher emphasis on heat and sunshine and less rain) and August 2004 started off similar to this but then everything shifted progressively further east which gave us some deluges, albeit often of a showery/thundery rather than persistent frontal nature. I don't recall ever seeing a summer low quite like Wednesday's though!

Yes, a much cloudier day in the areas that were projected by GFS to be cool. GFS was guilty of over-egging the low temperatures IMHO, but it evidently picked up on the advancing cloud sheet correctly.

"Unsettled and warm" is a fair description with low pressure dominating to the W and NW and feeding in warm west to south-westerly winds. Although the previous two days were sunnier than some people expected, today has had a fair amount of cloud roll in off the North Sea. Tomorrow this cloud will probably retreat northwards, affecting most of eastern Scotland, while NE England should brighten up with the winds turning southerly. There are two main areas to watch for thunderstorms tomorrow- south-west England could see some elevated storms coming in off the continent at around 3-9am, and then the Midlands and possibly Lancashire and Yorkshire may see some thundery downpours break out in the afternoon and evening. Many parts of East Anglia, the SE, and the east Midlands and central southern England will probably have a dry sunny day with temperatures in the mid 20s. With fronts spreading from the west, tomorrow looks set to start off dry, sunny and quite warm in eastern areas, but dull and wet in the west, and then the rain belt will head north-eastwards, perhaps becoming more showery and thundery as it heads into eastern areas. The front looks set to be slow-moving on Tuesday, which will bring pulses of rain and possible thunder to eastern areas while western areas are likely to brighten up with scattered showers. Thursday's depression is worth watching as the GFS shows a very deep low with some extremely heavy rain spreading in on Wednesday night, though ECMWF and more especially UKMO show a much weaker low which perhaps suggests that GFS is overdeepening it (not for the first time). Extended guidance from the ECMWF shows the mean trough just to the west of Britain promoting a continued changeable but fairly warm outlook.

I remember a week's holiday in Argentat near the Central Massif, France, where the weather followed the sort of "script" that Miguel Hugo Roberto described on most of the days- including the displays of altocumulus castellanus early and late in the day, before the cumulonimbus towers shot up past 6-7pm. Re. the trough on Sunday, I think Stormmad26 is right, and it's quite a common occurrence for bands of precipitation to travel at 90 degrees to the movement of individual pulses or showers when we have troughs/fronts about. The main concern for South-Westerners is that they may yet again become the breeding ground for thunderstorms over the Midlands and parts of NE England. Thunder potential for the south-west will most likely depend on elevated instability imported from the near-continent.

Historically, many heatwaves have originated from this kind of evolution, where we get a build of pressure following a polar maritime incursion, giving generally dry sunny weather with modest daytime warmth and chilly nights, and then highest pressure transfers into the North Sea sending hot airmasses up from the continent. The reason for the lack of notable heat this time around is probably the short-lived duration of the southerly airflow plus the nearest hot airmasses being a long way away to the south (the further away the hot airmasses, the more sustained the S/SE airflow needs to be). When we get the tropical maritime airmass scenario with high pressure coming in from the SW and low pressure over the top, the weather often starts off fairly cloudy with warm sticky nights- again the clearest route to a hot sunny spell from there has the high pressure extend eastwards pulling up drier continental air.

I'm not sure where this cloud is going to come from over the next two days, as the satellite images suggest that yesterday's front over SW England has fizzled and that all that remains is patchy convective cloud plus some patches of wispy high cloud in the north. Cloud will of course arrive associated with the Sunday/Monday breakdown, but not It's possible that the GFS's low temperature projections for northern Britain may arise from overestimating the extent to which south-easterly winds bring suppressed temperatures and low cloud from the North Sea. I think "haar" will certainly become an issue over eastern Scotland and coastal NE England but it is hard to see temperatures being held back at 16-18C in inland regions.

The FAX chart does look appealing for storms in many places including south-west England, with convergence likely over Devon. I agree that storm lovers in SW England have had a pretty rotten time of it over the last two years. On average (over the period 1981-2010) Exeter is about as thunder-prone as Newcastle, but that certainly hasn't been true recently!

Negative posts complaining of a "meh" type of outlook are guilty of either downplaying the current outlook, or trying to speak for everyone regarding preferences (i.e. anything less than sustained high pressure being a disappointment). Today's outputs are a world apart from what we saw during the first half of the summer, and the synoptic setup progged for the weekend onwards is reminding me a lot of the Julys of 1994 and 1995, with southerly tracking depressions held out in the Atlantic and high pressure to the NE with frequent southerly winds over the British Isles. It is possible that the models may be underestimating the jet stream and that we might see the Atlantic trough shifted further east promoting a cooler, cloudier, changeable type of outlook, but over the last few days the outlook has shifted from "cyclonic with a slight southerly bias" towards "strongly southerly". As for the upcoming anticyclonic interlude, there will be a fair amount of cloud in the S and SW of England tomorrow, slowly retreating westwards, and a scattering of showers mixed with sunshine further north, but by Thursday it looks to me as if showers will be very isolated while frontal cloud will retreat to Ireland leaving Scotland, Wales and England with skies varying from clear to partly cloudy. The thundery breakdown for the weekend is still "on" for the south-western third of Britain on Sunday, but has been delayed until Monday further north and east. However, I concede that it won't be warm and sunny everywhere, with eastern Scotland likely to see some low cloud off the North Sea.

4 consecutive days of thunder at Sandhutton (N Yorks) too, although I missed the fourth one as I was travelling down to Exeter- caught a couple of heavy showers on the way down though (around Leeds). The first two, for which I was around, were pretty spectacular though! The previous three days all had as much shower activity as I expected, though thunder was if anything more widespread than I expected it to be on Saturday and Sunday. However, today was a real surprise- I only expected a few scattered showers to develop over northern England.

It depends on whether by "winter" the post meant "meteorological winter" (which is of course December to February) or "wintry weather", and the latter strikes me as more likely. I think most parts of Siberia tend to turn cold and snowy by mid-October, although in years when we get a persistent west to south-westerly flow extending from the North Atlantic right into Siberia, it can take until mid to late November.

It might turn out to be a cloudy high (these things are hard to predict, and I remember underestimating cloud amounts from an anticyclone in mid-March this year) but I'm unable to find evidence for any significant likelihood of it persisting beyond Wednesday. On Wednesday it's pretty clear why southern England will be cloudy, with a front straddling the south, but areas from the Midlands northwards should still be reasonably sunny: http://www.wetterzen...pics/brack1.gif Onto Thursday and the forecasters at Exeter expect the front to fizzle out as it heads northwards and the relatively strong sun at this time of year should help to burn off a lot of the associated cloud: http://www.wetterzen...pics/brack2.gif For Friday, not a front in sight: http://www.wetterzen...pics/brack4.gif GFS indicating limited cloud cover across the country on Thursday with the exception of Ireland where the front may maintain a bit more strength as it drifts north: http://nwstatic.co.u...ecdba9725881c8; Cloudy weather looks likely over the south tomorrow and again on Wednesday, I'm not denying that, but otherwise it doesn't look like a particularly cloudy high to me- certainly nothing like the setup of late-August 2008 when we had a persistent tropical maritime regime over the British Isles sending in a constant supply of cloud.

Yes, it's the same process, and on rare occasions it can produce thunder, particularly around Merseyside and into west Manchester, but thunder potential overnight may be limited by the advancing high pressure.

I've been guilty of underestimating cloud amounts in anticyclones before, notably around mid-March this year, but I'm struggling to see where we're going to get much cloud from during Thursday-Saturday bar the usual "haar" coming into eastern Scotland and coastal fringes of NE England. The next two days may see the weather turn cloudier in the south and south-west of England though as a front takes up residence.

Mostly dry today with some sunny intervals but generally a lot of cloud. There was one sharp shower at 12 noon and a few rumbles of thunder to the north-east, but most of today's showery activity has been east of here. A max of 20.6C in the back garden, 19C at nearby RAF Topcliffe.

Largely missed out today, there was a sharp shower at around noon and a few distant rumbles but since then the shower activity has been concentrated to the east of here. I'm not too disappointed though as the GFS precipitation outputs had suggested it for a while, and of course I had a lot of thundery activity over the past two days.