casparjack

I am with the above comments about the side-bar, even on a large monitor it feels very cramped and the content is a distraction. Each to their own though, so an option to disable/enable would be great.

Hey ho indeed...

I completely agree, however the issue I rather suspect, is that they consider the data to be 'theirs', rather like the jealously guarded attitude to sharing NWP output.

I was looking at the CET earlier to compare with my own records - Philip Eden has the latest figures on his site as 5.2c (-0.3c) - so just below. http://www.climate-uk.com/ Not wanting to be contrary, just trying to help...

'Weeks to come out of' - says who and why - you can't come out of something you're not already in? Sounds like pattern matching again to me, (or something worse), unless you provide justification for your thinking with charts, which would be a novelty for the members in here. If the high to the NE does come into play, can you explain how you foresee the jet running over the top as you keep describing, surely what you mean is that there will be no link and the jet will continue to run between the two. As ever you're trolling the thread trying to wind people up, you've been calling what you rather poorly explain above since the end of November in a number of threads, yet here we are on the evening of the 12th December and we are yet to see what you describe, with the models only really hinting at its development by T216 - acknowledged by a majority of experienced players as real FI. You always appear to be so certain in your statements, yet they don't become reality as far as I can remember; go on prove me wrong with evidence of past success...

I was just looking at the T240 frames from the 12z ECM and exactly the same occurred to me, the build in pressure to the East is very apparent, as is the Azores high, in between we have a real squeeze going on; any number of outcomes are possible from here, though one of them could be mild...

Maybe I missed it amongst all the bickering, but I haven't seen any reference to the FAX chart for 0600 tomorrow; it shows the 'middle' low at 943mbs, this still has the potential to be very notable...

It would be unlikely to fall afterwards!!

Not trying to be pedantic, but meteorologically speaking you have had a frost, 0.0c is freezing point and is therefore classed as an air frost from a recording perspective. My first air frost of the season yesterday morning, 10th December -0.7c.

I think they'll say it's going to be very windy on Thursday night and Friday!!

It may well be the outcome as you have been predicting, but as I said in my post we'll have to wait and see - I still have my doubts, you clearly don't... Some members, but not me. I come here to discuss what the models show not semantics - leave it to the mods!!

I think that's spot on - if you predict something for long enough then eventually it will happen; I'm afraid we've seen him do it too many times before. Who really knows right now which way it will go, it does look as if the stormy spell has about a week to run, but really after that any number of scenarios could emerge - though I accept that at the moment deep cold is perhaps the outsider as far as December is concerned.

CC I fully appreciate what you're saying here and I too would love to see a prolonged cold spell; however I think what many people fail to appreciate, is that although you say one third of winter is already written off, what we are experiencing at the moment and expecting in the next couple of weeks is really typical British winter weather so we shouldn't actually expect anything else despite what we coldies might wish for...

I have to say that whilst there may ultimately be some merit in pattern matching, I am yet to be convinced; I just feel there are too many variables to be taken into account for it to be a credible and viable form of prediction. Our relatively small available sample (100 years or so of reliable chart records) is just too narrow for any really robust method to be devised in my opinion. I don't doubt the potential for it to follow as before, but it could just as easily do something totally different as the models currently indicate - they could and no doubt will change though in the next 96 hours or so...

I've taken out the charts to avoid using loads of additional space, but considering they are the 'ensemble means', they all look remarkably similar to me, apart from subtle differences in the position of the high (none of them favouring real cold for the UK) - I think that gives a very strong and perhaps largely unwelcome signal.

Well I think that's exactly it, the majority of the 'casual' posters in the MDT are treating December 2010 as the norm now and expecting it to repeat every winter - then getting wound up when equivalent conditions don't show in the model output; the more experienced amongst the members will of course appreciate that last Dcember was a real rarity, probably 100+ years repeat probability and I therefore find it refreshing to come in here and read 'grounded' discussion on more realistic events such as cold snaps (2 or 3 days in my definition) the like of which before 2007/2008 we would have been grateful for. I find it fascinating to consider what type of cold events we can achieve with unfavourable 30mb temperatures and John's venture into linking temperature spikes with subsequent cold snaps/spells certainly deserves a great deal more effort and a much broader sample - whilst unlikely to be totally conclusive I see it as another individual brick in a very large wall.

To add to those in Durham, Blanchland gets cut off regularly as does Muggleswick - drifting in an Easterly being the most likely cause...

It really isn't a case of how low in terms of there being an absolute limit, there are too many other variables to consider, though obviously the lower and denser they are the greater (and quicker) the heating effect. The difference is that often high cloud heralds a change in air mass so often it might have a marked effect, though sometimes high wispy cirrus could pass through, but actually have little impact on the temperature, maybe stopping it falling rather than actually raising it. Whereas patches of Cumulus (perhaps former shower clouds) drifting through on a Pm air mass might raise the temperature back a couple of degrees above freezing, then once they have cleared it falls back below 0c again. There are various formulae that one could consider, but that gets into the realms of NWP; you need to remember that on a clear, relatively still night there will be a temperature inversion, with the air closest to the ground being the coldest then rising to perhaps 1,500 ft, then beginning to fall again as one would usually expect in relation to the altitude.

...and what's it like outside?

Cold front just gone through here, rainfall not as notable as further North though; temperature has dropped from 12.2c to 7.6c (currently) in about fifty minutes...

Backtrack is right, clouds emit infrared radiation (in this instance described as downwelling infrared radiation - though they emit it in all directions), it is efficiently absorbed by the ground and whilst the passing cloud is present has the effect of raising the temperature of the air nearest to the ground, this is obviously particularly noticable on a frosty night. On the subject of wind, the simple explanation here is that it mixes up the air and the cooler air nearer the ground (cold air is dense and tries to find the lowest point) is mixed with the slightly warmer air aloft, the windier it is, the less effect the radiaitve cooling will have and accordingly the minimum temperature will be higher than it would have been on an 'ideal' perfectly calm night (though in reality these are almost non-existent as air will always be subject to eddies due to uneven terrain and therefore is never totally still). Hope this helps...

51.4mm here as of today; that's about 60% of our long term average, but we remain around 270mm short on where we should be against the long term annual average figure.

I agree there hasn't been a great deal of snow either, though we did get snow throughout December 2010 (unlike you guys further North and East) and three times in January 2011, but nothing since. This feels less unusual however to me, as I have become resigned to the lack of real old fashioned frontal snowfall in the past 15-20 years, but I don't recall having so few air frosts, that's why I wondered if it was my imagination or something more noteworthy...

To be fair whilst I appreciate your point, there is no such thing as the law of averages - all such events are unrelated and not affected by what has gone before - flipping a coin for example, you might get fifty heads in a row, but the chances of getting a head on the next flip are still 50/50 - weather is just the same, though infinitely more complex, we could just as easily get five Novembers like 2010 in a row or never see another one in a generation; Mr Data's post today about cold spells around 22nd November is a perfect illustration of this...

As I collated the figures for October and started to compare the year with others, apart from the obvious rainfall deficit (272mm here to date against the long-term average), it occurred to me that there have been very few air frosts this year. My recent counts are as follows: 2007 - 32 exceptionally low 2008 - 47 2009 - 46 2010 - 83 2011 - 28 to 13th of November with little prospect of any for at least a week based on current modelling (17 in January and 9 in March, just 2 in February). We haven't yet had an air frost this season, the lowest temperature being 0.9c on 7th November, with only three ground frosts. The annual average at Shobdon (Uk MetO) just five miles from here is 47 - they are slightly lower than my station and often in marginal conditions will record a figure just below 0c when my station is just above, but over a whole year this balances out. It follows that to even approach the average we'll need to see another 20 air frosts in the remaining 48 days of the year, unless we see a dramatic pattern change very soon, then I doubt we'll even get close. Interested to know how this compares with other people's records...