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casparjack

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Posts posted by casparjack

  1. 12 minutes ago, Nick L said:

    Agreed. I lived in Oklahoma for a year and we had this page for all the official sites:

    WWW.MESONET.ORG

    It's fantastic with data every 5 mins. There's no excuse why a world-leading institution like the Met Office can't put something like this together.

    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.

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  2. We have a strongly +ve NAO going into next week and HP to the NE will not be coming into play other than to perhaps form an elongated High with the jet running over the top. As I said earlier, the scenario shown on the GFS and ECM at T240 is one that takes weeks to come out of generally speaking.

    '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...

  3. Putting aside the earlier timeframe and looking towards the weekend and into next week we see the Azores high making an attempt to ridge into southern Europe. One could look at the later output and think its a slam dunk! However the big 3 outputs at 144hrs could offer something different, the UKMO and GFS eject some energy east and the ECM holds the European troughing. The Azores high can not move east if the Russian high locks in low heights over central Europe, before some in here get their t-shirts and barbecues out again I'd wait a while longer.
    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...

    post-7301-0-55792100-1323719508_thumb.pn

  4. There still hasnt been an air frost here yet this season. Today was painfully close with a min of 0.0C.

    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.

  5. What is a usual following on from persistent low heights to the N and NW is development of the downstream ridge, be it the Azores High edging NE towards France or a proper Bartlett. Obviously this is coupled with the Stratospheric profile at the moment.

    Next weekend looks a classic trigger for this to happen, with a toppling High following a brief North Westerley, this typical leads to a minimum 10-14 days mild zonality thereafter. And looking at the extended GFS and I expect the ECM at what will be around T216, its going to be a long haul to get out of that sort of synoptic.

    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...

    In the interest of balance, there are those that do exactly the same with regard to cold, but for some reason that appears far more palatable to most members. If people don't like Ian's posts hit the ignore button, it's not rocket science.

    Some members, but not me.

    I come here to discuss what the models show not semantics - leave it to the mods!!

  6. The main snag there is that, if I remember rightly, Ian was calling this scenario on at least a couple of occasions when high pressure was set to ridge into Europe (most notably around now) and it didn't happen. Thus, while he might turn out to be right eventually, it won't mean that he was right all along.

    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.

  7. Zonal as far as the eye can see at the moment I'm afraid. Effectively one third of winter is written off now IMO. January and February are dependent on whether we can see some form of vortex break up and a warming of the stratosphere. I must say this pattern looks increasingly entrenched at the minute.

    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...

  8. The system progged for next week reminds me a lot of the system we had on the 16th-18th January 1999:

    http://www.wetterzen...00119990116.gif

    That one brought some gales and also some snow to parts of Scotland associated with a frontal system, and then a few days of sunshine and showers (wintry in the north and in some upland parts of Wales and the Midlands). It's worth noting that during January 1999 the pattern flattened out into a milder form of zonality into the last third of the month with high pressure over Europe, which again highlights the strong historical precedents for that evolution, but pattern matching is of only limited reliability and the GFS and ECM ensembles don't show much support for it at the moment.

    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...

  9. Big difference at just +144 with the ensemble means of GFS/ECM.

    GFS

    ECM

    Though even GFS turns more zonal later. My bet is on ECM/UKMO unsettled zonal outlook.

    GEM looking very unsettled and zonal too

    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.

  10. I think it really depends on what cold solution people are on the look out for to be honest.

    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.

  11. For NE England - in terms of towns Consett for sure, I would have also said Alston but it is Cumbria so I'll give that to the North-west.

    For villages - I'd go for one of the upland Durham villages, maybe like Lanehead, Wearhead etc, though Waskeley might end up being an unlikely winner due to its susceptibility to picking up heavy snow from a nor'easterly wind too.....

    I also think one or two of the Northumbrian villages in the Cheviot area might also get messy.....

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

  12. 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.

  13. 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...

    :)

  14. 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...

  15. i think iceberg hit the nail on the head with his post it is only novemeber last novemeber dec was a rare event so to expect the same out come year in year out would go against the weather law of averages.

    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...

  16. 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...

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