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Model Output Discussion - The Run In To Christmas


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Posted
  • Location: Portrush. (NI) UK
  • Location: Portrush. (NI) UK

    Forget the "is it going to snow in my backyard" for a second and look at those wind arrows! Dangerous storm that could be which I should imagine ties in with Ian F twitter comments earlier. Gales, (storm surge in North Sea) Rain and northern Snow in that system, not nice.

    This is Icelandic style LP system as PV is displaced Eastwards, the UK's proximity to PV is at point blank range when trigger pulled.

    Extreme for East Coast and Dutch.

    North Sea floods of 1953,1962 in mind a repeat has been along time coming

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    Unfortunately, there needs to be a recognition that if we share at *this tentative juncture* the exact nature of what we have as Ops Centre guidance, certain individuals will inevitably extrapolate/wa

    If the UK can't get cold from an upstream pattern with a negatively tilted troughing setting up over the ne USA , indeed the best set up since two winters ago then I will seriously consider throwing m

    The good news just keeps on coming!   Upstream pattern is falling into place to deliver what many people in this thread want to see, NCEP give us the best update since winter 2012/2013,  indeed I'm

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    Posted
  • Location: suffolk
  • Weather Preferences: deep snow/warm sunshine
  • Location: suffolk

    This is Icelandic style LP system as PV is displaced Eastwards, the UK's proximity to PV is at point blank range when trigger pulled.

    Extreme for East Coast and Dutch.

    North Sea floods of 1953,1962 in mind a repeat has been along time coming

    only this time last year some places on the east coast actually had higher levels than 1953
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    Posted
  • Location: Hollywood, Worcestershire
  • Weather Preferences: Thunderstorms, Cold & Snowy
  • Location: Hollywood, Worcestershire

    This is Icelandic style LP system as PV is displaced Eastwards, the UK's proximity to PV is at point blank range when trigger pulled.

    Extreme for East Coast and Dutch.

    North Sea floods of 1953,1962 in mind a repeat has been along time coming

    2013?

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    A weather bomb with winds, snow and storm surges, Nathan Rao has just wet himself ....

     

    The UKMO has that same shortwave ejected ahead of the LP at T+144

     

    Can someone explain please the term ejected? Ejected how, why, where, or is it simply a surface low pressure sytem moving quickly.

    genuine question and you are not the only one to use the term.

    help please?

     

    Googled and so far no mention even on the NOAA site for both east and west based meteorology in the states?

    Edited by johnholmes
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    Posted
  • Location: leicester
  • Location: leicester

    Just when you wanted the models to get some unity, GEM pushes the pattern further east:  attachicon.gifgemnh-0-222.png

    to be fair no disrespect to the model and you but that's at 222 hours and whatever gem shows hardly ever comes to reality!! Maybe once in a while!! But its funny cos everything was further west and now everything east!! I think in the end everything will hit the uk direct lol!! And the USA will always be colder i think cos more land and less sea to pass through! ! Always a higher chance of getting harsher cold there!! But its all the way at 324 hours so lets not worry about that!!
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    Posted
  • Location: Cobham, Surrey
  • Location: Cobham, Surrey

    This is my first post and i think quite a sensible one... and by the way thanks to everyone on this forum as it really helps someone like me understand the models..... i am one for getting carried away as i love the snow... but i think we should look at the models with a tad of caution..... because just yesterday they where indicating average temps..... i just think we should wait till the end of tomoz to get really excited..... but i agree with everyone that low pressure system looks a beauty and supposed to be driving back from north yorkrshire of a hill on the 27th... if that comes off i don't think i will be going anywhere!

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

    Looking at the complex situation with the ongoing movement ie positioning of the rise in pressure to the west and switching run to run shortwaves and all gives credence to what Tamara has been saying in the switch in the general pattern change heading in to January.Way in deep fi there are signs of things changing to the east which she also mentioned!fascinating mo atm be it a bit frustrating

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    Posted
  • Location: Otley(Leeds)
  • Location: Otley(Leeds)

    If this run verifies then it will be one of the biggest weather events ever, severe gales, monsterous blizzards dumping several feet of snow on favoured areas, storm surges, unreal

     

    A bit OTT don't ya think.

     

    Lost count of the amount of times I've seen severe storms like what the gfs is showing completly dissapear nearer to the time.

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    Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

    Much better prospects for a post Christmas cold spell in the latest runs,so far.

    The main difference upstream today has been the inland runner!That is a low within the Canadian trough around T96hrs which runs north up the east coast of NA instead of pushing into the Atlantic.

    http://www.meteociel.fr/ukmo/runs/2014121912/UN96-21.GIF?19-17

    http://www.meteociel.fr/ukmo/runs/2014121912/UN144-21.GIF?19-17

    We can see the movement on the above links.

    This enables better Greenland ridgin downstream and enables the cold air to cut south.

    Looking very interesting after Boxing day with the possible development of a deep low running into the cold air to our north.

    Edited by phil nw.
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    Posted
  • Location: HILL OF TARA IRELAND
  • Weather Preferences: SNOW ICE
  • Location: HILL OF TARA IRELAND

    great charts I note gfs p was on to something a few days ago when it had that nasty low in the north Sea and it's on to in again in 12z.The only thing that concerns me is its 8 days away,and I've seen these lows pushed further east with consecutive runs.I have to admit I have a feeling something big is comming for us poor coldies and the toes and fingers are crossed!

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    Posted
  • Location: st albans
  • Location: st albans

    If this run verifies then it will be one of the biggest weather events ever, severe gales, monsterous blizzards dumping several feet of snow on favoured areas, storm surges, unreal

    Nothing like a bit of over exaggeration John! The reality is never like the charts at that range. Good to see the predicted long wave pattern solidifying in the modelling. Still a little way to go before the actual solution comes Into view

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    Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

    Can someone explain please the term ejected? Ejected how, why, where, or is it simply a surface low pressure sytem moving quickly.

    genuine question and you are not the only one to use the term.

    help please?

     

    Googled and so far no mention even on the NOAA site for both east and west based meteorology in the states?

     

     

    hi

     

    As I understand it...it is when a LP system in situ is squeezed and some of the energy is forced out of the LP:

     

    post-14819-0-68356100-1419009735_thumb.p post-14819-0-32131300-1419009744_thumb.p post-14819-0-99519000-1419009751_thumb.p

     

    In this instance the original LP remains in situ and the daughter low is ejected NE into the jet.

     

    Not sure it is a Met Technical term though!!

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    Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

    I wonder who will get the real cold (as per usual): 

     

    attachicon.gifgfsna-1-324.png  

     

    Clue: That is the US under there!!

    Didn't a similar thing happen in 1963 cold East northeast United States at the same time the uk was in a seasonal ice age.

    On our side lots of beautiful charts but are we anymore near in the evolution and we're does fi stand!.

    I'm not convinced county wide but certainly confident further north.

    -8 upper air would be enough to see snow fall and stick around.

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    Posted
  • Location: Coulsdon, Surrey
  • Location: Coulsdon, Surrey

    Nothing like a bit of over exaggeration John! The reality is never like the charts at that range. Good to see the predicted long wave pattern solidifying in the modelling. Still a little way to go before the actual solution comes Into view

    Oh I agree, at the moment it is "eye candy", but IF it verifies or does not downgrade significantly it is a storm that will go down in the history books

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    Posted
  • Location: Osmotherley, North Yorkshire
  • Weather Preferences: Extreme Events
  • Location: Osmotherley, North Yorkshire

    I observed it then but winds speeds were a lot less in comparison 200 kilometre per hour winds where not present.

    I don't usually post in here but the storm last year was quite extreme and caused a fair bit of trouble, also the wind speed was pretty high as well for some areas.

    http://www.bbc.co.uk/news/uk-25220224

    post-17858-0-18579500-1419010700_thumb.g

    post-17858-0-99299900-1419010746_thumb.j

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    Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

    Much better prospects for a post Christmas cold spell in the latest runs,so far.

    The main difference upstream today has been the inland runner!That is a low within the Canadian trough around T96hrs which runs north up the east coast of NA instead of pushing into the Atlantic.http://www.meteociel.fr/ukmo/runs/2014121912/UN96-21.GIF?19-17http://www.meteociel.fr/ukmo/runs/2014121912/UN144-21.GIF?19-17

    We can see the movement on the above links.

    This enables better Greenland ridgin downstream and enables the cold air to cut south.

    Looking very interesting after Boxing day with the possible development of a deep low running into the cold air to our north.

    Also East based negative nao which is never a bad thing that's if the gfs is right.

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    Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL

    Great call by Steve Murr - my optimism has increased to 65% of a decent chance of fleeting severe cold. Not exactly long lasting but packing a punch, Going by my gut I expect the cold to wane and then amplify towards mid January, many background telecommunications support an very respectable looking January. Back in November I went for a bitter cold January the OPI team and the guys in the stratosphere thread have induced this ideology successfully, really its just been a matter of when and how...?

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    Posted
  • Location: .
  • Location: .

    Very good 12z GFS main, GFS parallel and UKMO. Let's see how ECM shapes up. Having held a lone flag these past 36 hours it would be sod's law to see ECM revert.

     

    Such has been the model volatility that we need to see Saturday and Sunday runs come in behind a cold Christmas season setup (accepting a few hiccups). If Monday morning's 0z outputs are clear and the ensembles mostly match then it's game on. Meantime we need to be tempered, not because that's always right but because of the recent model yo-yo ing.

    Edited by West is Best
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    Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

    Also East based negative nao which is never a bad thing that's if the gfs is right.

    The good thing is that the holding back of energy from that Canadian trough and better downstream ridging is almost within the reliable.

    This raises the hope that we will end up with some type of cold spell a few days later.

    Anyway we will soon see what the ECM makes of it.

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    Posted
  • Location: st albans
  • Location: st albans

    Well, the models seem to firming up on this cold trend! huzzah

     

    I just wondered why Michael Fish has forecast an average Christmas, with mild air pushing in after boxing day towards the weekend? does he have privy to data otherwise known to the rest of us?

     

    At least he did say he could be wrong, and as we all know, he's got it wrong before...!! :shok:  :clap:

     

    Looks like a chilly xmas and boxing day under that ridge. breezier on xmas day in the ne with a chance of some wintry showers in the prone areas on a norwester first half xmas day. boxing day looks questionable later on (could be an approaching little depression or the ridge could hold a bit longer). possible fog issue on both days further south

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    Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

    At last!

    Good consensus building for what we can expect to see develop over Christmas and into the New Year across the output.

    I fully expect the best ECM we have seen for some time in terms of cold being modeled this evening.

     

    There is still potential for things to go wrong but the output has very much moved in the right direction through today though GFS ensembles are a little slow to pick out the detail of how shortwave energy will interact with the trough but that is to be expected. Confidence is increased because the higher res of the operational runs is important for detail.

     

    We have two areas of shortwave energy to watch just after Christmas, one to the NW and one to the W/SW, timing is important though not actually crucial so long as the closed low to our SW does not push NE and only spits off shortwave energy as it disrupts to our SW.

     

    See the following GFS chart with shortwave energy NW and W/SW of the UK.

     

     

    gfsnh-0-168.png?12

     

    These shortwaves, often the demise of a cold spell are actually just what is needed as the initial trough is too shallow and weak to displace the spoiler Azores high and back the ridge West and thus amplify the pattern enough to bring in the colder polar air.

     

    Here they have merged to form low pressure over the UK which will then phase with the main trough to our NE. This period will likely be wet and windy and not cold bu it should also be brief.

     

    gfsnh-0-180.png?12

     

     

    Now the low moves East and merges with the main trough displacing the Azores high to the South and ridge to the West and amplifying the pattern, dragging in much colder air from the N/NE

     

    gfsnh-0-228.png?12

     

    Why post just one run and detail the synoptic?

    Because this is very much the typical pattern being set up and what the consensus is being built around.

    The details will vary but if the models are right about how they are handling the shortwave energy then cold is guaranteed from this pattern.

     

    Currently the ensembles want to move the PV back West in the later output and are reluctant to build high pressure over Greenland, in stead offering a 4/5 day cold snap before the Atlantic pushes back in, but this is very much against the background signals so if things turn out along the lines of the above which is currently looking good then we can expect large and rapid upgrades to the severity and longevity of any cold into the New year.

     

    If ECM goes the same way this evening and there is a firming up tomorrow I would happily forecast a cold spell in the run to New Year with many areas likely seeing snow.

    No more wobbles please! :cold:  :cold:  :cold:  :help:

    Edited by Mucka
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