Nick B

Hook echo off Kent coastline? .... maybe not, just looked that way for a moment!

Seems like the shadow of an aeroplane contrail cast from above... don't forget, at our latitude the shadow will not be directly below the contrail itself.

Utterly correct, but they will not be as long as powerful and wealthy individuals wield power in the way nation states are governed (i.e. forever!). Because true sustainability (locally-based permaculture as well as ensuring oil reserves are carefully managed / eaked out) flies in the face of current economic policy of virtually every developed and developing nation on the planet, it is so much easier to deflect attention to the great bandwagon of global warming, CO2 etc. The term consensus is used as a political baton to beat down gainsayers through carefully controlled media, and of course to keep the public attention focused on the great roundabout argument of global warming, in order to milk as much tax from individuals as possible. So those in power remain that way through their own lifetimes, which is as far as any of them are prepared to look ahead.

Hmm, well you see I think usually my posts tend to be a bit boring and dry, so I couldn't help this one... Anyway, agree with you about the models atm - nothing particularly inspiring (yes, there is the ECM 144hrs, however, given how in the current setups we've had the HPs and LPs shifting around by the odd few hundred miles to take them to the wrong side of marginal for us for anything even up to 24 hours away, this output is treated with a barrel load of grit by me). To get any decent wintry weather deep snow that will last a reasonable length of time (5 days plus) I think we'll need to see upgrade after upgrade from this point on. Chances are now getting much slimmer. We can of course get the odd fun blast of Nrly/NErly full of heavy convective snow showers during the next couple of months but for more than this we do need a run of luck!

Yum! What type of confection? Should we stand outside with something to catch it?

5.4 deg C please.

Wellingborough too. Looking at the radar, it seems to now be intensifying in a separate band north of the main area, and we are benefitting atm. Light for now, however has been enough in the last few hours to give about a cm on the roads here.

Scatter begins in earnest from Saturday on that chart. FI should begin at least then. Up to that point it's staying cold and could well get colder..

As per my earlier concerns with this low, imo we are now within 24 hours of the point where the positioning of this LP system needs to be firmed up properly in the models for the majority of the country to get more than cold rain. However, even if it does turn out to be a damp squib, could it open the door for a colder synoptic pattern afterwards?

Fair enough but do we hold on to it in time for any decent amounts of precipitation? Slight precipitation is a big no-no for snow, of course. That's the question for many now. I was never under any illusion that a 'even larger teapot' couldn't produce proper long lasting cold. That has been categorically shown to be beyond question. Just how much more can we have though?! ...(please?)

Interesting point you make about the tendency I have highlighted above. I am concerned whether, even if the placement of next week's potential LP system were further east, there might be there a significant chance that exactly the same scenario could apply to systems originating in and sweeping down south from the Arctic? i.e. As we move closer towards the reliable (for me well within 72 hours atm) might we see the penetration of the cold air to the South held back, keeping this as a feature only for mid-Scotland and further north? I'm not sure at all, but I wonder if this has previously happened. Also, the seas to the north of Scotland are not as cool as the North Sea, so if flow was slacker, surely we will then see more moderation and end up with a week of sleet, cold rain and the occasional wet snow flurry melting away? Trying not to be downbeat, but I see this as another distinct possibility, and am therefore curbing my enthusiasm with a healthy dose of realism / pessimism - therefore anything we receive after this point I now view as an unexpected bonus. In mid-Northamptonshire we may possibly have seen less lying snow - about 5cm at most - than almost anywhere this winter (except maybe for SW Cornwall, or did they get some?) and I would rather like a winter wonderland for a good week! Yes, there's bags of potential but I look at these charts and with the good stuff potentially heading a bit too far west for most of us, I am again looking at what I see as very marginal set-ups, and feel time is now beginning to run out for a real dumping of deep long-lasting powder snow for all, which, let's be honest, is the jackpot most of us addicts are particularly interested in! Btw, if Ireland get everything and we get nothing I am still happy for you guys over there! Could you just nudge it our way though?!

Japan, North island? Stunning scenery (alpine in places), warm/hot summers, cold and very snowy winters.

Missing data aside, I would say only look at it to get idea of next 24-36 hours because of issue over Scandinavian SW. Beyond that and who could back any of them based on the last week's changeable output. TEITS's wait and see approach may be necessary not just for next few hours, I guess, but perhaps even for next couple of days just to see what may pan out over the weekend. Low confidence you bet!Especially so, given remarks by Chionomaniac just now in Stratospheric thread.

The below quotation is from the ECMWF Ensemble page as posted by GP (I hope they don't mind). I suppose the questions below are directed in particular to anyone who has professional or in-depth experience of how models work. 'In the European Centre for Medium-term Weather Prediction, the operational model is re-run at a lower resolution (the control run) and this is then repeated 50 times, each with slightly different starting conditions. These ensemble runs are shown in the graph above as the grey lines; the average is shown in yellow.' (my emphasis) 1/ What is different about the starting conditions? Is it the choice of exact data used, or is the data very slightly manipulated by the modelling tool to represent tiny changes in real life which would naturally be happening? 2/ Are the ensemble runs done at a lower resolution purely for speed (i.e. if data is very slightly manipulated anyway, to create the range of possible outcomes, there is no point in having fine tuning)? Is it because of the ways the data is supposed to be interpreted (i.e. saying, "Oo, I wish we could have seen how number 32 got down to -20 deg C for next week" is pointless since it was never designed to be seen - but rather to show the likely spread of possibilities, with the yellow average being the mid-point of greatest likelihood)? 3/ When a model is upgraded (like the recent Parallel GFS becoming the new GFS), what is changed? Actual measured data? Programming within the modelling tool itself? Thanks for any answers Nick

Dewpoints for most locations above 0 deg C on that chart. May well usher in something colder afterwards... no, not in the immediate aftermath. Precipitation type says snow for many, but dewpoints still a bit on the high side if that warm sector verifies - too early to be looking at precipitation then anyway. LPs tracking too far north on this run if most want snow in the medium term. Then we are the block and much of Europe continues in the cold, though under the anticyclone would bring sharp frosts if not ice days. Some will say bin it, I am sure...

2.3° for me please.

Yes, still FI, but that Easterly just goes on and on and afterwards we could end up with potential for a Northerly reload with the big -AO conditions already there. Absolute biting cold for well over a week. Now, how can we drag that run into the reliable timeframe?! Though it goes on so long that by the time the first part of the Easterly was with us, the end would still be well in FI. The Easterly shown makes its way across the Atlantic almost to Newfoundland at times. Hmmm. A few burst water mains around with the ice days that would follow that one! Plenty to get through - we haven't even had our Northerly yet. Plenty of time for downgrades yet (and of course upgrades, which on that run is a little scary!).

Your point is particularly relevant if you really take into consideration GP's latest contribution to the In Depth Technical Discussion thread last evening. Enjoy it, the cold may well stay with us for some time yet. This would also echo JH's warnings to us and BFTP seems to be hinting about February though he is waiting until mid-month to let us have his prognosis...

Oo that looks like they will just pass north of Wellingborough. Maybe some more out off the Norfolk coast a bit further south might make it to ours. We had the dregs off the last decent Peterborough shower but it looks like the track is more ENErly now rather than NErly. At least Sat pm into Monday is looking promising. Though sheer depth is fun, for me if there's more than about 10cm and it's the crisp dry stuff that sparkles and packs hard, dry and crunchy underfoot rather than melting, that's perfect. Would of course settle for 40cm of it too! For your last forecast this evening you deserve a dumping! Mmm some pepping up south of where yours sprung from. If they can just make it all the way across...

Hmmm. Not actually an outlier I would say, in that it has support from just a few of the members, but it's of course not a run to be welcomed by those wishing to see the very cold pattern extend. However, there is still time for either upgrades to the models, though I feel we are definitely heading towards a lessening of cold in the medium term. It would be fun to see plenty of snow for many areas in the way this is worked out, but this will not really be known until the event itself is almost upon us. There is of course plenty of time and opportunity over the course of the next couple of weeks and into the longer term for the next cold spell to appear over the horizon - as far as I am aware things still hang in the balance for a cold vs mild February? Don't forget, in the past, this type of winter has often lasted well into March...

Excellent post. Good discussion.

For all their problems with getting supplies of grit occasionally, you'd have thought that if a spell is forecast to councils in good time, as this has been, then the chances of having deep snow in the main strategic routes in C London would be fairly low even in a good snow outbreak, simply because the dispersal and amount of grit available now must be much greater than the 60s and 70s (faster lorries, able to carry more, better autmatic spraying, use of computers to determine fastest routes for covering large areas of map etc.). The side-streets, however, would be a different matter...

Agree! Slight jest. Not having the NW Extra radar I can't be absolutely sure, but are my eyes deceiving me in seeing a slight pep-up of precipitation just beginning NW of Birmingham (on raintoday)? If so, this would tie in with your mention (I read about second -hand) of a separate low pressure area forming further SE over the UK and might explain how and why the precipitation bands were brought to a halt? Also would it have anything to do with the relatively strong 700 hPA vertical winds being forecast (or did I interpret that incorrectly as well?!)? <BR>Hmm... actually I think my eyes were deceiving me after all. It doesn't appear to be happening.