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Model Output Discussion - Colder spell ending, what's to follow?


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Sigh....given we have crossed swords before over the notion of bias, and I have put my position on it very clearly out there for others to see, I'm disappointed to read about it again. But seeing as y

Hi the link doesnt exist any more plus the locale we would want to look at isnt on that small chart! Anyway evening All > Lots to be optimistic for tonight all detailed before the 18z Is

Evening All - A very disappointing 24 hours where the very promising charts have not evolved into anything more than a fleeting prospect of deep cold > I held off all the while the UKMO contin

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Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    2 minutes ago, DiagonalRedLine said:

    Seems like there is currently some good support for something chilly to develop towards Christmas.

    The 3 longer distance models at 240 hours - 06Z GFS and the 00Z ECMWF and 00Z GEM - showing up the mid-Atlantic ridge quite nicely:

    06Z GFS

    4637F2D2-CA4D-4B42-9149-7FA241771222.thumb.png.0350c3b0fe4e5dae57957f70832c5954.png7CEE0110-A5B7-4CE6-B296-5E1D4BFBD74B.thumb.png.1bb4bb251373294d0db7f897bc43690e.png
     

    00Z GEM

    316F4906-FE09-4574-A5E8-823455D34A6F.thumb.png.df7d80dd066fab3fe96bb089a046d4ac.png384EC1BC-D3FF-4027-BB6C-2B132200A3B8.thumb.png.0ec3560c352a13e650f8cca7dd245cce.png

    00Z ECMWF

    F8E370A1-2FD9-43AD-941F-F393DAECC077.thumb.png.a709c7f335932d16e72f883b803b8ac3.png21E7F4F1-CA1B-4FB0-988E-A307CFE7EE8E.thumb.png.7c7ddab1687888b3ee6271443b49217a.png

    GFS probably the messiest with how it plays about with the Atlantic amplification to our West. Less pronounced than on the other 2 models, but still a pretty good area of High Pressure to our West. Would be chilly. More of a cyclonic flow from the North-West and North on both the GEM and ECMWF with a chance of some showers, wintry at times of high ground, but perhaps to lower levels on the GEM as -5*C 850 hPa line gets down into Northern France. 

    Both the GEFS and ECMWF ensemble means between day 8 and 10 supporting the amplified ridge shifting East into the mid-Atlantic to our West upstream:

    GEFS ensemble mean

    45AFE3A4-2C9A-42C9-AACA-6269C50A2636.thumb.png.be81ac36df959978a338e7c8b8b85a1a.pngBF44D456-CCC8-419F-9143-88FEC90C54D6.thumb.png.f53a5eae40c1e3227081786278910a35.pngFFA5341A-7CA4-46C5-B8EF-3DBADB10538D.thumb.png.55f57128babcb06235c796fa790f571c.png

    ECMWF ensemble mean

    10231399-2586-46EB-9534-A0B5CB13B5DB.thumb.png.05a94b6c5a5005c21b08552e5ad93de2.png59E14E67-4D9C-4618-B5A1-40C0C020B235.thumb.png.cb5c99a40b83be272923b2b0f6f19498.png1E65EAE3-24FE-40BA-BFC0-9D822DC4A3CB.thumb.png.1923d5b49c4c6847200c5fa4e631ef00.png

    The ECMWF maybe a little less amplified in the Atlantic than the GEFS mean. Both, though, showing a signal for amplification with Low Pressure over Northern UK moving further East into Scandinavia allowing colder weather from between the North-West and North take over. No evidence on these charts for the Vortex rock about over Greenland, which makes these amplified patterns around the Atlantic sector be easily possible. And that prospect as well of the MJO, some spoke off, possibly going into some high-level phase 6 territory. That of which being kind to some amplification to the West of the UK. (Sorry if some of these charts have already been posted).

    The GFS Jet stream chart at 240 hours illustrating some buckling of the Jet upstream to our West. A wavy pattern that maintains ridging into the mid-Atlantic. No flat, powerful, Jet stream powering through to flatten out the ridge at that time frame 

    1F208074-AFEE-41D6-A5F6-3775A48B644E.thumb.png.a9d306dfec5b483f438ae23f87fa8e38.png
     

    Both the London and Aberdeen GEFS line graph 2 meter temperature ensembles show enough of a trend for things to cool down towards Christmas.

    79F0EA29-BB3E-4E12-A461-BB5B93E506B9.thumb.jpeg.0a11bdc82fecb48e48bb9a05d16aacc0.jpeg330C1D41-E022-486A-AB97-6ED677C4D7C5.thumb.jpeg.ddff71ae09eb26c4f4a9da59c86ae6db.jpeg

    Aberdeen, in particular, may drop close or around freezing levels. Definitely a real wintry flavour their. London ensembles have a little more scatter towards Christmas and beyond, but still looks like a trend to something chillier, like with Aberdeen. I guess some of this, however, depending whether a chillier Polar/Arctic Maritime flow can penetrate far enough South to reach Southern UK areas, which I think is very possible. Need to also have a pretty clean evolution with the link up of that hang back Low to our South-West taking a mostly Eastwards track, and then linking up with the main UK Low Pressure across our South. This should also help with supporting the amplified ridge as it crosses East into the Atlantic. More of the smaller details really.

    CE16FEDD-3CD8-4059-95FE-A674D3B03E1D.thumb.jpeg.0d569b43cf93c685a526085ddcfa0e97.jpeg
     

    Overall, things look rather sweet for the cold weather fans towards Christmas from this mornings charts. No signs of any really deep cold, plus the GFS is a bit messy with its evolution. Not quite certain enough yet I feel whether this would be something transient, or something longer lasting (although there doesn’t seem to be any real hurry to flatten out the likely Western/mid Atlantic ridge). Would be very seasonal and it could be cold enough for something white. Both on the ground and precipitation-wise, particularly over Northern areas of the UK.

    Not really experienced deep cold in my lifetime in the UK, any idea why the control hates us later on? 😉 

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    Posted
  • Location: Broadmayne a few miles north of Weymouth in Dorset
  • Weather Preferences: Snowfall
  • Location: Broadmayne a few miles north of Weymouth in Dorset

    I Have just been flitting around a few model and ensemble runs and would thoroughly recommend coldies and snowies take a look at the extended gfs 0z control run 384 -840.  Just follow it right through to the end, it is indeed a thing of joy and beauty.

    just a titbit below

    GFSC00EU99_720_1.png

    Edited by Broadmayne blizzard
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    Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)

    Growing support for a cold spell after Christmas. This is the coldest set so far for that period . This is for London / south as well! 

    855DBB5A-A95E-4A4D-8252-58B0104F162D.jpeg

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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.

    Cold is coming, this is the max temperature, looking good.

    image.thumb.png.9e461a3d3c3ac13621127da88ab8931e.png

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    6 hours ago, Griff said:

    Why didn't anyone show me yesterday's GFSP? 🤔 

    2139136671_gfsnh-0-300(2).thumb.png.aba9ebac35fd3c98872e9509c487800b.png

     

    More importantly this morning's gem says keep calm and carry on... 

    121599819_gemnh-0-144(7).thumb.png.b183f38c5ed2ad02448ddb4e615e9f43.png

    615908729_gemnh-0-240(5).thumb.png.ad0ff5aeb879d062fb041c203008ff14.png

    Is today's GFSP broken? Proper question, ta. 

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    Posted
  • Location: Abergavenny
  • Location: Abergavenny
    24 minutes ago, Broadmayne blizzard said:

    I Have just been flitting around a few model and ensemble runs and would thoroughly recommend coldies and snowies take a look at the extended gfs 0z control run 384 -840.  Just follow it right through to the end, it is indeed a thing of joy and beauty.

    just a titbit below

    GFSC00EU99_720_1.png

    Just viewed this run, it is completely outrageous. Definitely a coldie at the controls.

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    Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.
    9 minutes ago, Tim Bland said:

    Growing support for a cold spell after Christmas. This is the coldest set so far for that period . This is for London / south as well! 

    855DBB5A-A95E-4A4D-8252-58B0104F162D.jpeg

     Of note that there are several members colder than the op in the days following Christmas a couple even tap -10 which is my benchmark for decent cold. 

    One might also say that the cold grouping is in the ascentancy post Christmas..

    Nice plot 🙂 thank you

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    Posted
  • Location: Sedgley 225metres above sea level
  • Weather Preferences: Summer heatwaves and electrical storms, and fidgid Arctic type winters
  • Location: Sedgley 225metres above sea level

    Like others have said,most definitely interesting NH synoptic appearing...consider what we were locked into last year,and all of a sudden things look quite rosey.

    gensnh-4-1-384.png

    gensnh-7-1-372.png

    gensnh-9-1-300.png

    gensnh-12-1-360.png

    gensnh-16-1-312.png

    gensnh-19-1-348.png

    gensnh-20-1-288.png

    gensnh-21-1-312.png

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    Posted
  • Location: Strood, Kent, 19 feet above sea level
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Strood, Kent, 19 feet above sea level

    Is it possible for those posting loads of charts to add them side by side? It's becoming an absolute nightmare to scroll using a mobile.

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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.
    Just now, steveinsussex said:

    For 6am

    Gonna Be Colder Earlier Then. 

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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.
    1 minute ago, Frosty Winter said:

    Again, this is one ensemble member 16 days away at 6am so it really doesn’t tell us much at all.

    Tell that to Jon Snow 🤣

    Anyway

    Atlantic Low Lingering. 

    gens-4-1-384.png

    gens-2-1-264.png

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    Posted
  • Location: NW LONDON
  • Weather Preferences: Sun, sleet, Snow
  • Location: NW LONDON
    9 minutes ago, MATTWOLVES said:

    Like others have said,most definitely interesting NH synoptic appearing...consider what we were locked into last year,and all of a sudden things look quite rosey.

    gensnh-4-1-384.png

    gensnh-7-1-372.png

    gensnh-9-1-300.png

    gensnh-12-1-360.png

    gensnh-16-1-312.png

    gensnh-19-1-348.png

    gensnh-20-1-288.png

    gensnh-21-1-312.png

    With a set up like that we will be needing sleet depth charts:reindeer-emoji:

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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.
    5 minutes ago, Frosty Winter said:

    This is one ensemble member 16 days away at 6am so it really doesn’t tell us much at all.

    One day I will learn

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    Posted
  • Location: South-West Norfolk
  • Location: South-West Norfolk
    8 minutes ago, Sheldon Cooper said:

    Gonna Be Colder Earlier Then. 

    And warmer later...

    Love your enthusiasm, but think you may need to temper your posting a little.

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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.

    Everyone has a bias and I'm A Ramper so no need to Criticise My Every Move. 

    tenor.gif.86eed92c08a7e7890fba81229058c585.gif

    Atlantic low on the Cards. 

    gens-5-1-336.thumb.png.cfbd50a83e342ff758012f5924a18971.png676592321_gens-27-1-288(1).thumb.png.9d798cb8238c01029cc114f07bcf252c.pnggens-2-1-300.thumb.png.b9f5ddc46986391b865941af80a1daac.png

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    Posted
  • Location: Cambridge
  • Location: Cambridge

    As others have said, everything pointing in the right direction on the GEFS. But we'll need the EPS pack to run with this signal before we get too excited - those of us who've been around for a while will be able to recount many times when the GFS or GEFS  did a mad one and wound up leading us astray. Other models clearly toying with a similar notions but as xmas week approaches let's see how far they take it - still plenty of time yet for this to unfurl in both  directions. 

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    Posted
  • Location: Birmingham (Solihull), West Midlands
  • Weather Preferences: Sunshine, thunder, hail & heavy snow
  • Location: Birmingham (Solihull), West Midlands
    1 hour ago, Griff said:

    Not really experienced deep cold in my lifetime in the UK, any idea why the control hates us later on? 😉 

    To be fair, we don’t seem to get deep cold often. Most of us would probably be happy having something chilly and seasonal, along with the chance of something white too (though not the end of the world if the chillier period towards Christmas doesn’t deliver. January or February could offer something) 😉

    One reason the GFS (00Z) control run I think seems to hate us is that although, synoptically, it looks interesting for a time, that Azores Low to our South-West gets a bit stuck. Blows up a bit. The high heights to our South-East over Europe at first get in the way. Got a pretty Greenland High from the Azores ridge, although other Lows in the Atlantic get stuck as the high heights to our South-East fight back. Would be one of the things to watch out for to not get a Western based negative NAO pattern with cold weather avoiding us to the West. Which is also why I feel the handling of that Azores Low and the heights over Europe is going to continue to cause the gears of the models to grind at times. Until at least they get a better handle of the situation.  
     

    2D265C71-3045-4B2E-9E8F-E7C40799EBF1.thumb.png.40b93449f2fea2fecc9f452a5c136f17.pngD8557072-66A6-42E2-A3D1-ACCB290F7D1D.thumb.png.ec9adebceb57a001eb77f2803f7b8c6a.pngD2607EEF-339D-473D-B5A2-6DE0CBF2192D.thumb.png.13c81ec75aa2458448724708b7f6bce5.png4D906C07-E3FC-4E9F-82A4-4E69C4EFE36C.thumb.png.3b9e83a1fc305574d602a2162b679628.png

    The 00Z control run finishes off with High Pressure building over Eastern UK, then collapsing against the pressure of the increasing Low Heights to our North-West.

    3759CE31-36FD-49C5-812C-5DF8D8DC285D.thumb.png.e0f6e9d8fa9a098f725fcc574511c385.pngD5861D0E-3746-4826-A36B-4BF2CD331F7E.thumb.png.ebdd3a3cd13cc03503aa9f30272525b2.pngF2D5ABF5-049A-4C3C-9859-3ECBA7965689.thumb.png.50d4478072a62f42b15d13b8c612da14.png

     

    The 06Z GFS control run, while synoptically not the same as the 00Z one, has the same problem of Low Pressure to our South-West being naughty. Gets stuck again to our South-West bringing milder air up over Southern UK from the South. Probably also thanks again to those high heights to our South-East over mainland Europe getting in the way. And the Low just struggling to get to the East of the UK failing to link up with Low Pressure across Northern/North-Eastern UK. The Low just fills and the Azores High builds East over the UK and towards Scandinavia. 

    8093FAE8-4A9C-4F89-8106-68BDE6676510.thumb.png.074d41ab5e23f4107122fe3154462710.png3E8F5881-0F72-49A0-A295-C9B563BA92EF.thumb.png.f6e21698779cc2fa1946b0a18e29f874.png8C539157-ECDC-4BB4-997E-B1C859D72BCD.thumb.png.7ad1abfbe6874f20848f96993e99041a.png1D32E6C4-D245-44DA-80A6-80388B81A8FD.thumb.png.e7bddfcd2510e06a7154b165e4c709ce.png464BE220-18FD-48FC-A6E4-F0247CD025D9.thumb.png.bb97dbb3d6c3ea85aec3611440ee6d6d.png

    Edited by DiagonalRedLine
    Typos
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    Posted
  • Location: Cambridge
  • Location: Cambridge
    8 minutes ago, Sheldon Cooper said:

    Everyone has a bias and I'm A Ramper so no need to Criticise My Every Move. 

    tenor.gif.86eed92c08a7e7890fba81229058c585.gif

    Atlantic low on the Cards. 

    gens-5-1-336.thumb.png.cfbd50a83e342ff758012f5924a18971.png676592321_gens-27-1-288(1).thumb.png.9d798cb8238c01029cc114f07bcf252c.pnggens-2-1-300.thumb.png.b9f5ddc46986391b865941af80a1daac.png

    I know you're still learning this stuff but this isn't all right. The member on the far right contains a small polar low running down the eastern UK with a cut-off icelandic high - that is far from Atlantic driven weather. Similarly the second frame does show several lows in the atlantic - including insanely stupid ones which is why we shouldn't examine individual members for detail - but it also shows a ridge of higher pressure north of Iceland. The first frame is classic GFS but is admittedly Altantic dominated

    And anyway, all of these frames are at +itdoesntmatterhours so best a) ignored and b) ignored and c) glanced at for nothing more than cursory trends. On the whole, save yourself the emotional turmoil of looking through the fine lines at this range - it's basically computer generated long term guesswork. Fun and potentially relevant for trends, but nothing more 🙂

    Edited by ITSY
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    Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Thunderstorm.
  • Location: Woodchurch, Kent.

    Well it's been a fun filled day we've still got the 18z runs and Remember, it's over a week to go still until the day that we want Snow At Least.

    We can't even trust past 5 Days.

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