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Posted
  • Location: North Hampshire
  • Location: North Hampshire
    1 hour ago, Steve C said:

    Is the 0.87 factor just a good rule of thumb? I'm thinking pressure doesn't increase / decrease in a linear fashion through the depth of the atmosphere. Would an extreme (say) 950mb or 1050mb surface pressure test the 0.87 factor quoted?

    Just interested, as I've wondered about this previously. ?

    For those who know any fluid dynamics it's just hydrostatic balance...

    dp/dz = - (density * acceleration due to gravity)

    dz = - dp / (den * g),        density of air = 1.225 g/m**3, g=9.81 m / sec squared

    So change in height = change in pressure / (about 12) - a factor of about 0.83?     (give or take pressure units!  Pascals ---> mb)

    The density of air varies quite slowly at sea level, so the factor should be pretty constant...!

    Edited by February1978
    typo
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    For those who think the SSW was a bust take a look at this at T+3   Then look at the NW/SE jet axis over us, then look at the fact that the downwelling has been delayed but is just und

    Feel I have an apology to make.  If people are wondering why this thread vanished for almost an hour, basically I went ahead a locked the thread first. Then, went and hid it. Was feeling fed

    Leaked express headline for tomorrow.   #sorrynotsorry

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    Posted
  • Location: Leigh-on-Sea
  • Location: Leigh-on-Sea
    1 minute ago, sparky1972 said:

    afternoon all, dont know about the hunt for cold, i think we have found mild, lol temps forecast to climb to 10/11c over the next cpl of days, cant see a return to cold from there, HaHa, i do so hope that all us coldies are rewarded for our patience this winter , im looking forward to reading everyones views on this afternoons/evenings output.

    Have you read this thread lol? Or was that a joke? 

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    Posted
  • Location: uxbridge middlesex(south east england)
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(south east england)
    10 minutes ago, sparky1972 said:

    afternoon all, dont know about the hunt for cold, i think we have found mild, lol temps forecast to climb to 10/11c over the next cpl of days, cant see a return to cold from there, HaHa, i do so hope that all us coldies are rewarded for our patience this winter , im looking forward to reading everyones views on this afternoons/evenings output.

    Another 1 who has'nt been taking there meds!!!.

    And walks around blindfolded!!!

    images (6).jpeg

    MT8_London_ens (18).png

    Edited by tight isobar
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    Posted
  • Location: frome somerset 105m ABSL,
  • Weather Preferences: cold snow, thunderstorms
  • Location: frome somerset 105m ABSL,
    6 minutes ago, sparky1972 said:

    afternoon all, dont know about the hunt for cold, i think we have found mild, lol temps forecast to climb to 10/11c over the next cpl of days, cant see a return to cold from there, HaHa, i do so hope that all us coldies are rewarded for our patience this winter , im looking forward to reading everyones views on this afternoons/evenings output.

    Funniest thing I’ve heard all day, good one

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    Posted
  • Location: Rhoose, South Wales
  • Weather Preferences: snow, thunderstorms
  • Location: Rhoose, South Wales
    6 minutes ago, sparky1972 said:

    afternoon all, dont know about the hunt for cold, i think we have found mild, lol temps forecast to climb to 10/11c over the next cpl of days, cant see a return to cold from there, HaHa, i do so hope that all us coldies are rewarded for our patience this winter , im looking forward to reading everyones views on this afternoons/evenings output.

    Think you need to read the last few pages for the possibilities of cold next week !

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    Posted
  • Location: spalding, sth lincs
  • Location: spalding, sth lincs
    10 minutes ago, Rambo said:

    Have you read this thread lol? Or was that a joke? 

    it was a joke, i know temps are forecast to be a bit milder tomorrow and saturday, then its looking like the real cold will arrive soon after, well hopefully. lol  bbc forecast for MBY for tommow is 11c and saturday 10c though

    Edited by sparky1972
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    Posted
  • Location: Study: University of Reading - Home: Keynsham, Bristol 40m ASL
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Study: University of Reading - Home: Keynsham, Bristol 40m ASL

    By T132 on the ICON 12z, the building blocks are in place for a decent north-easterly by T180... hopefully!

    Azores high moving westwards with heights extending towards Greenland, Arctic high beginning to edge south and low heights moving into Southern Europe.

    Edited by Ben Sainsbury
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    Posted
  • Location: Straiton 145m asl
  • Location: Straiton 145m asl
    3 hours ago, snowray said:

    See, JMA was on the ball after all last night.?

     

    Para even gives us our Greenland high by the end of the run, fab run!?

    gfs-0-192.png

    gfs-0-240.png

    gfs-0-384.png

    gfs-16-360.png

    State of emergency in Scotland if that verified ??

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    Posted
  • Location: sheffield
  • Weather Preferences: cold ,snow
  • Location: sheffield

    Parra showing where fi is again ,around the 120-144 mark!!!!

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    Posted
  • Location: Sedgley Black country 731ft 222 metres
  • Location: Sedgley Black country 731ft 222 metres

    Icon 12z  similar to its 0z run  just that the pattern seems to be around 30hrs earlier. 

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    Posted
  • Location: Liphook
  • Location: Liphook

    Icon looks much too strong for the south unfortunately with too much mild air coming into the south. May even be too much for Midlands as well but we will see. All complex is still moving ESE nicely.

    ICON looks WAY too strong, pressure below 965mbs which seems highly unlikely and blows our cold pool to kingdom come!

    If it is that strong, it will probably delay cold again for another 4-5 days given the way the flow behind it slackens up....even the next slider would be screwed by that due to the lack of cold air!

    Edited by kold weather
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    Posted
  • Location: st albans
  • Location: st albans

    Icon phases the Atlantic with the scandi trough - causes the sw/ne nuance on the base of the troughing that some runs have been showing .... that’s the 20% total eps clustering from the 00z run - was well outvoted ! 

    see if ukmo heads that way in half an hour 

    Edited by bluearmy
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    Posted
  • Location: South Staffordshire
  • Weather Preferences: Snow
  • Location: South Staffordshire
    3 minutes ago, bluearmy said:

    Icon phases the Atlantic with the scandi trough - causes the sw/ne nuance on the base of the troughing that some runs have been showing .... 

    see if ukmo heads that way in half an hour 

    The only concern is that the ICON has been similar to the ECM recently in terms of output. Let's see what happens and where we go through the remainder of the afternoon... we did mention that FI is T72 and so nobody can be calling 'DOWNGRADE' every 5 minutes throughout the entire of this evening's suites. 

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    Posted
  • Location: Liphook
  • Location: Liphook
    10 minutes ago, bluearmy said:

    Icon phases the Atlantic with the scandi trough - causes the sw/ne nuance on the base of the troughing that some runs have been showing .... that’s the 20% total eps clustering from the 00z run - was well outvoted ! 

    see if ukmo heads that way in half an hour 

    Probably a similar number on the 06z GFS ensembles, it was there as option but hardly favourite.

    Of course with this winter, that 20% will definitely be the right option, everything has to be difficult ? 

    system also is rapid on the 12z ICON, pressure already down to 975mbs in the Atlantic at 120hrs and south of Greenland and then it phases as you say. I highly doubt its going to come in either that fast OR that strong at that point.

    Edited by kold weather
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    Message added by Paul

    Please ensure that the majority of your posts in this thread are model related - a theme of model discussion needs to run throughout.
    Some off topic chat and reactions are ok, but please use other, more relevant threads for entirely off-topic chat (such as snow reports, met office forecasts and general chat/moans about the weather or this winter).

    For more no banter and just model discussion please head to the new focused model thread - this is also a great place to post (or cross post) your longer model summaries or thoughts around the models.

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