Thundery wintry showers

A shift back towards a cold and potentially fairly snowy outlook on this morning's model outputs. Today and the weekend will be mostly dry and sunny apart from wintry showers near north-facing coasts, but we do have an area of organised precipitation moving south-eastwards tonight. http://cdn.nwstatic.co.uk/gfsimages/gfs.20121130/06/24/ukprec.png 850hPa temperatures will be above the -5C mark as the band approaches, but generally below after it clears, so it will be very marginal for snow. The most likely outcome at low levels will be sleet/rain initially, with some backward edge snow possible. Monday's potential snow event for northern England is still "on" but looks like it will mostly arrive overnight- by daylight hours it will probably have turned back to rain. Next week is progged to have a couple of northerly outbreaks which look rather more potent (at least in terms of 850hPa temperature) than modelled on previous days, and with disturbances running into the polar airflow, chances of some marginal rain/sleet/snow events with snow always more likely on the north-eastern flank of the systems, with rain in the south and west of them. It does indeed look like the extended (T+192 to T+240) outputs from the GFS and ECMWF are potentially setting us up for some sort of easterly incursion, with a moderately cold continent to tap into, but the ECMWF ensemble mean suggests that there is considerable uncertainty over the prevailing pressure patterns in this period. Temperatures probably no higher than average though.

4.5C max here, some cloud is now spilling down from the north but I think skies will be clear enough at times overnight to allow another air frost.

The temperature dropped a fair bit after the showers cleared out into the North Sea, -1.1C min here, currently 2.3C and rising. There will be a band of wintry precipitation moving SE late on Friday and early on Saturday according to the GFS but temperatures will be very marginal and I won't be expecting any lying snow from it. Monday's snow event is now starting to look too marginal for low ground also.

Surprisingly, a couple of "rogue" showers made it as far inland as Sandhutton in the past hour- still just rain though, with a current temperature of 2.6C.

From an IMBY perspective, a synoptic setup like this at some point during the winter please: http://www.wetterzen...00119550220.gif ...but preferably not too many easterlies like these: http://www.wetterzentrale.de/pics/archive/ra/2002/Rrea00120021209.gif

Had a fair number of rain showers here at Sandhutton yesterday and this morning, some of which were moderate to fairly heavy, but predictably showers have died back to the east now that the wind has backed to a N to NNW'ly. Neil Bradshaw is registering 3.1C at South Shields so still a pretty feeble northerly so far in terms of cold.

That assessment of the ECMWF chart probably stems from the blues shown on the colour scale of Meteociel. I think the T+216-240 northerlies on both the ECMWF and GFS would probably produce mainly sleet and rain showers for eastern England. Here are the 850hPa temperatures: http://cdn.nwstatic....ecmt850.240.png The cold snowy potential has been toned down on today's runs, but in truth, even the earlier UKMO runs probably suggested just a couple of days of generally snowy weather for the east due to erroneously sending the North Sea trough southwards too quickly. Trough activity will bring precipitation inland on Friday/Saturday according to the GFS, but with marginal 850hPa temperatures (-3 to -5C generally) we are probably looking mainly at sleet/rain at low levels with snow on hills. The UKMO/GFS have also toned down the potential for frontal snow next Monday but the ECMWF outputs would still support a fairly widespread frontal snow event. The disagreement over Monday's weather is also consistent with Paul's comment about T+96 being the point at which the GFS ensembles start to differ considerably- the "big three" models also start to deviate at around that time.

For the next two days, a northerly airstream will keep most places dry and sunny, with the winds blowing "down the spine" of the country and keeping showers largely restricted to north-facing coasts. Showers have come a long way inland on today's NNE flow, but by tomorrow the winds will be around to the north. During Friday and the weekend we have a fair amount of uncertainty as a trough will move into the North Sea. The GFS is showing a fair amount of shortwave activity around the trough, bringing belts of showery precipitation inland, but these shortwaves are associated with pools of milder air, which means that precipitation would be of a wintry mix for many rather than snow. http://cdn.nwstatic..../72/h500slp.png http://cdn.nwstatic..../h850t850eu.png Meanwhile the UKMO and ECMWF show a "cleaner" northerly flow, which means temperatures generally low enough for snow (850hPa temperatures generally -6C or below) but with showers more likely to be generally restricted to north-facing coasts. The UKMO outputs have the trough sinking as far south as East Anglia before the northerly runs out of steam, and this would be likely to bring sleet/snow showers a fair way inland off the North Sea late on Saturday and into Sunday, though there isn't much support for this from the ensembles. Personally I feel that the GFS is rather overdoing the shortwave activity and that the most likely outcome is along the lines of the ECMWF operational run- the trough in the North Sea may cause wintry showers to develop more widely across the British Isles on Saturday, with a slight westerly component to the flow bringing sleet and snow showers into Wales and SW England off the Irish Sea. Further ahead, I sense significant potential for a frontal snow event on Monday, particularly for southern Scotland and northern and eastern England, similar to the one that hit NE England on the 4th December 2008. After that, the east to north-easterly incursion shown by the ECMWF operational run is unlikely to come off, but if it did, we would be talking showers getting a long way inland off the North Sea, perhaps falling as a wintry mix near east-facing coastal fringes but falling and lying snow elsewhere. The ECMWF ensemble mean and the NOAA 8-14 day forecasts are my main ports of call for the T+192 to T+240 timeframe and they suggest a generally cold and cyclonic outlook, with marginal snow events more likely the further north you are, but not as cold as the ECMWF operational run. For those suffering from flooding, the next five days will be somewhat drier than recently which will help to alleviate the problems, but with low pressure set to take control into next week, there is no guarantee that there won't be further flooding problems then.

Yes, the UKMO and ECMWF are making rather more of that North Sea trough which would presumably promote showery activity further inland and perhaps the odd more organised belt of precipitation. The UKMO continues to look the most potentially snowy of the three IMHO, but even the GFS is now suggesting wintry precipitation getting inland for a time on Saturday.

The main issue that we have is that when the colder air arrives the winds are projected to back northerly, and pretty much down the spine of the country, which will help to restrict sleet and snow showers to coastal fringes unless we get any significant trough activity. Troughs are not out of the question though, as it will be a cyclonic/northerly regime. I think many of us are in with a shot at frontal snow on Monday, especially to the east of the Pennines- perhaps reminiscent of the 4th December 2008.

I think of Summer 1998 as a fairly typical example of a "westerly" summer- a succession of lows bringing a lot of cloud, rain belts interspersed with some brighter showery interludes, and the occasional short-lived ridge from the Azores High bringing dry cloudy weather to the north and sunshine to the south. Having said that, June 1998 was notably wet in many places and July 1998 was unusually wet in Scotland. July 1998 contained a fair number of active "convective days" in Tyneside from the showery westerly flows in between the rain belts, but these were mixed with a large number of cloudy days with the odd bit of drizzle- the latter must have been particularly prominent over eastern and southern England as statistically July was rather dry but dull in those areas. August was memorable in Tyneside for its distinct lack of "weather"- mostly dry, quite breezy, a fair amount of cloud, the odd bit of sun and the odd bit of rain, but it was very much a north-south split month and Heathrow Airport had 40% above average sunshine thanks to the persistent ridges from the Azores High.

Note that many earlier model runs had the -5C 850hPa isotherm struggling to penetrate beyond northern Scotland, so although the east to north-easterlies that they showed may have brought more precipitation, most of it would have been rain at low levels. 850hPa temperatures look set to dip below the -5C mark over most of the country this week, though on the other hand, the winds will be northerly and this will mean a more pronounced "wishbone effect", with sleet and snow showers restricted to windward coasts. If this was March or April we would no doubt get a fair amount of homegrown shower activity in a setup like this, though of course the stronger sun would generally mean daytime thaws in the sunshine in between the showers. Troughs, however, cannot be ruled out as they do sometimes turn up at short notice in these cyclonic/northerly regimes, and they could bring rather more widespread snowfall. The UKMO outputs were too progressive at sending the trough in the North Sea southwards which is why they kept showing a north-easterly or easterly flow, but in fairness the model has only done a slight backtrack this morning (today's T+120 output bears a lot of resemblance to yesterday's T+144 output) while the ECMWF has flipped about rather more. On the basis of this morning's outputs frontal snow could well be quite widespread for a time on Monday, with Scotland and the north and east of England most likely to see the white stuff. Behind the frontal system there will be some quite chilly polar maritime air due to the NW-SE alignment of the jet, so the subsequent Atlantic-driven weather could well feature some marginal snow events in the north, with very little evidence of heights rising at high latitudes anythime soon and the likelihood of further northerly and north-easterly outbreaks.

I think there is indeed the possibility of a fourth option along the lines of what today's GFS 00Z/06Z and yesterday's ECMWF 12Z showed, involving a stronger Atlantic influence with low pressure to the north, but it doesn't look like classic zonality to me- we keep high pressure at high latitudes with little sign of the reformation of an organised polar vortex. Even the relatively zonal-looking outputs, such as the GFS 06Z, have temperatures generally near or below average with the jet tracking NW-SE. Also, the last few frames of this morning's ECMWF 00Z run are far from "zonal"- we get an increased Atlantic influence but the high pressure to the north and west of the UK is still a prominent feature.

Yesterday's runs saw the UKMO and to a lesser extent GFS painting a snowy-looking picture and the ECMWF going for a breakdown into early December with a northern arm of the jet developing and lows heading across to the north of Scotland. It seems that the ECMWF and GFS have switched around- the ECM does show the Atlantic temporarily making inroads but the jet always remains titled NW-SE, while the GFS has a full-on breakdown. These sort of model switch-arounds cause a lot of forecasting headaches and the length of this cold wintry spell is still up in the air, though with a considerable amount of evidence to suggest that the GFS is being too progressive. The UKMO operational runs have been remarkably consistent up until now and this morning's T+144 output shows a pretty snowy-looking east to north-easterly flow with some of the coldest air getting down from the NE, but most of the other cold runs tend to favour a northerly with shortwaves out in the North Sea. The northerly type could still be quite snowy if the troughs in the North Sea help to generate more organised precipitation, but a "wishbone effect" is more likely when precipitation is generated mainly from cold air flowing over the comparatively warm North Sea. Meanwhile some relief coming up for the flooded areas as it appears that the persistent/frontal type rain will clear out of the way tomorrow leaving brighter weather and some showers, increasingly of a wintry nature, in the east of the country. It is probable that showers will be mostly of sleet and rain tomorrow, maybe sleet and wet snow in the north on Wednesday, before generally turning cold enough for snow at low levels by Thursday, but again watch out for the wishbone effect with winds likely to be from the north, rather than the north east as shown on the UKMO operational runs.

36mm in the 12 hours from 10pm-10am yesterday morning. Now up to 50mm in 36 hours.

The key differences around T+120 to T+192 are associated with the re-invigoration of a northern arm of the jet and building pressure to the south which, on the ECMWF operational run, ends up seeing low pressure systems track over northern Scotland by T+168 and cutting off the northerly flow. http://cdn.nwstatic..../ecm500.168.png The GFS 18Z also gets there eventually, but the lows coming in off the Atlantic keep filling out and sinking underneath the extensive Arctic blocking through the high resolution part of the run. For instance at T+168 we see the jet aligned NW-SE at our end of the Atlantic and keeping depression tracks to the south of the blocking, keeping us in a northerly flow: http://cdn.nwstatic....168/h500slp.png The ECMWF ensemble mean shows a fair amount of support for a breakdown of the northerly regime but at T+168-192 the operational is a clear mild outlier, as the ensemble mean 850hPa temperatures never get above the 0C mark. Even on the ECMWF the breakdown occurs at T+168, and in these sort of "northern blocking" setups I've known the models go for a breakdown as soon as T+120 only to ditch it completely (I remember a few UKMO runs bringing in mild SW'lys during the December 2009 cold spell for instance)

I don't think there is a significant chance of wintry precipitation across the region (except on very high ground) until Wednesday, when the cold airmasses will come down from the N and NE. There is still a lot of uncertainty over how much of an easterly component to the airflow there will be, so there is the possibility of a "wishbone effect" with showers confined to coasts, though the GFS 06Z also shows quite a few troughs which would bring belts of organised sleet and snow to some parts of the region. The UKMO/ECMWF evolution would tend to bring wintry showers further inland off the North Sea.

My experience over the last few winters has been that, on the whole, most people cope rather better than the media makes out, and so the accusations of the younger generations being "soft" are a bit wide of the mark. If you read the tabloids and hear the news the picture painted is usually a lot more negative than the overall reality, probably because the greatest negative impacts are the most news-worthy, and implying that the worst-affected groups are representative of the population as a whole makes for sensational headlines. When the local news goes around polling people for their opinions on the snow, they choose their groups carefully, e.g. elderly people waiting at bus stops and retirement homes, and so the prevailing responses are about how disgraceful the weather is because snowy weather makes it particularly hard for many of the fragile to get around. If they were to survey students and lecturers at a university campus for example, the responses would often be very different. However as many posts have noted, if we were to have a long cold winter with repeated severe snowstorms or, worse still, ice-storms, there would come a point beyond which the reality would be every bit as harsh as the media typically makes out.

Plenty of concerns re. flooding over the next few days before the wintry spell commences, with yet more moderate to heavy persistent rain following into south-western areas overnight Sunday/Monday following tonight's deluge: http://cdn.nwstatic....8/30/ukprec.png It's already looking as if what had, so far, been a fairly quiet November on the weather front is going to turn out as yet another wet month for most parts of the country. I am seeing a general trend in the model outputs for a northerly airstream to dominate from mid next week onwards, rather than an easterly or north-easterly. This should reduce the amount of mixing from the SE and thus guarantee temperatures cold enough for snow, but on the other hand, it also increases the chances of the airflow being mostly down the spine of the country which would promote a wishbone effect, i.e. sleet and snow showers largely restricted to north-facing coasts barring any trough activity. I am reminded a bit of how the synoptics looked at the beginning of December 1997, although it looks unlikely that the northern blocking will subside anywhere near as quickly as it did on that occasion. http://www.wetterzentrale.de/pics/archive/ra/1997/Rrea00119971202.gif The ECMWF and UKMO operational runs look more conducive to widespread showery activity in eastern areas as we get a significant easterly component to the flow at times, though the GFS may be the snowier bet for Wales and the high ground of SW England which sometimes pick up a fair number of wintry showers in N to NW flows.

The November/December 2010 spell consisted mainly of two severely cold and snowy spells- 25th November to 2nd December, and 17th-26th December. During both spells there was considerable disruption, but a quieter spell around the 3rd-9th December and a temporary thaw midmonth helped enable the authorities to get things moving again, and so many of us got by with just minimal overall disruption to our lives. In the meantime, the sub-zero temperatures were not severe enough for long enough to cause the likes of the National Grid to freeze over. I remember you posting that you aren't old enough to have experienced the winter of 1946/47- that winter would surely have been the critical test! I've posted earlier about breaking points beyond which I start hoping for a temporary thaw, but I rather suspect when it comes to experiencing a degree of cold/snow that would make me subsequently hope for mild dry winters, my breaking point might well be similar to yours. My enthusiasm for those sunshine-and-snow-showers setups, in particular, would have to take some extremely heavy battering through hardship for it not to come flooding back again straightaway.

I agree; if we had a repeat of 1947, the threat of our electricity & water supply sources freezing over may be less than in a repeat of 1963, but the travel disruption would be a lot greater. I think it's quite possible that a repeat of March 1947 alone could cause the UK more trouble than a repeat of the entire winter of 1962/63, as March 1947 had repeated heavy snowstorms followed by rain and gales with associated flooding and melting slush and ice. In 1962/63, in contrast, a large proportion of the snow in lowland Britain melted gradually during a spell of dry sunny weather in late February/early March and so flooding was far less of an issue.

I've been having a bit of amusement thinking of some uninformative answers to that question, like the following: 1. Cold weather is on the way because... cold weather is on the way. 2. Cold weather is on the way because... I said so. 3. Cold weather is on the way because... that's life. 4. Cold weather is on the way because... the GFS says so, and the GFS is the GFS.

Grit also leaves ugly brown patches everywhere and, if applied in a half-baked way, can succeed only in partially melting the snow, subsequently turning it to ice and making conditions underfoot more dangerous than if no grit had been applied at all. Thus I too prefer the "clearing the snow" approach to the heavy use of grit. Some good points about the way some people rely upon driving for their work in itself, showing that there is more to it in some cases than whether you can get to work or not. Taking the country as a whole I think most of us, with some exceptions, would get by alright with the transport disruption and many snow lovers would find that the benefits of the cold snowy weather outweighed the inconvenience- but more of us would be seriously tested if sources of core supplies like water and electricity were to freeze over. My assertions there are related to posts from Pennine Ten Foot Drifts back in December 2010 noting that the National Grid providers were worried about the freezing level penetrating well below the ground surface. Of course that would require several weeks of persistent sub-zero weather, so I doubt that a repeat of, say, 1978/79 or 1981/82 would get to that level.

Not everywhere has reliable buses. I suppose one could argue that someone in a cut-off area with a 4-hour walk to work could walk there from 5-9am, work 9am-5pm, and then walk home from 5-9pm and still have 12 hours for sleeping and eating in so "there is no excuse", but there are substantially greater health implications there than with someone who could take an hour or less walking or getting the bus to work. There's also the issue of those whose work involves travelling a lot and who are unable to carry out their work due to snowdrifts, ice etc. Tarring everyone with one brush due to the misbehaviour of some is the norm these days but it doesn't make it right.

Re. walking to work, it depends on how far you live from where you work, surely? In today's society a lot more people live a significant distance from where they work- a 40-minute walk to work could easily be coped with by most people but in some cases we'd be talking more like 4 hours. There is a problem with some people using snow as an excuse to stay off work when they could easily get in, but also one with people with genuine claims being tarred with the same brush. As for whether we would cope with another 1962/63, I think we would cope alright with a repeat of December 1962 and January 1963, but we may well struggle during February 1963. I recall that during December 2010, there were threats of the National Grid freezing over if we had a similarly cold January, and at that point we would have to make do without many of the things that we take for granted, so 6-8 weeks seems to be approximately the limit. After that, most of us would still survive but we'd have to make do with far simpler lifestyles. For me personally, my tolerance of cold snowy weather tends to drop if it turns to solid ice for a long period with no topups to cover up the ice, or if we end up cut off or deprived of electricity etc. for a long period (I'm thinking upwards of a week here). I find it hard to see myself turning my back on snow events altogether and saying, "I don't want any more until the next season", but I can certainly see myself hoping for temporary thaws to allow the National Grid to recover and/or remove the ice. This is a pretty high threshold- it was never crossed throughout November/December 2010- but it may well have been passed at some point during 1962/63. Overall though I think a repeat of 1962/63 would be rather easier to deal with than a repeat of 1946/47 (more serious snowfalls and a general shortage of sunshine in February/March) or, as Kevin noted, the ice-storm of January 1940.