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Model output discussion - into 2018


Paul
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    6 minutes ago, Catacol said:

    So - here we go: starting tomorrow the height rises to the NE begin to fade away SE under the influence of falling AAM via low torques, unhelpful MJO phase and background Nina forcing. Ventrice posted this today - atmosphere clearly coupled to the oceanic nina signal.

    DS8bUWnVMAAec0X.jpg

    The logical progression of this is that there is insufficient forcing over the next 7 days to change very much, and let's remember that ECM has an over amplification bias in the extended range - I'm not buying a major block arriving in 7 - 10 days. A coldish pattern with plenty of polar maritime influence... but for lowland south of England we'd need to roll a double 6 to get something significant and even then it would probably be relatively transient. For high ground and the north - plenty more snow potential through this period: always worth acknowledging that not everyone on NW is a lowland southerner!!

    But all is most definitely not lost. Taking apart the specific signals - as GP said a post or two ago - there is much for cold lovers to get excited about in the longer term.

    Frictional torques have reached their approx cycle minimum

    Frictional Torque

    and shortly they will start to climb again. Relative AAM has gone through the floor, down to -3SD at the moment and probably bottoming out at that point

    Tendency of Relative AAM

    With increases likely from this point as the atmospheric elastic band that constantly tries to keep momentum neutral at 0 kicks in. MJO currently in 2 but ready in around a week or so to move into 3 which has a much better composite for continental flow

    ECMF_phase_MANOM_51m_small.gif

    z500_p3_01_1mon.png

    What does this all add up to? Chasing shadows for another week via NWP... but from around about this time next weekend we might start to see some very good looking charts hitting NWP output for Jan 20 onwards... maybe a few days later. Frictional torques will lead +MT and combine with MJO phase 3.. well supported by the atmospheric instinct to wipe away that very low relative tendency in AAM. This will encourage steeper incline of the Nina jet into Europe (that Nina forcing will remain so I dont see a Greeny high and -NAO from this) and the scandy high properly fighting back west. Undercut scenarios a-plenty.... and with Strat interest aptly timed to kick in later in the month we may see something of decent duration. It is too far out for me to speak about duration with any confidence... but I think lag effects of MT and the strength of the spring may well help establish a durable and strong scandy high which is then hard to shift... so a week of something cold seems a decent bet and if it went longer then it wouldnt be a surprise.

    Eyes will be firmly looking for cold pooling over Eastern Europe in the meantime. Seeing -12 uppers heading for Greece in the modelling for next weekend could well end up being a rather good thing in the longer term...

    Is the frictional torque projected increase what will untimately drive mountain torque and subsequently some of the Strat warming events projected on the NWP output, also I'm led to believe that the MJO in the bottom right quadrant is sometimes the catalyst for +ve E.Asian mountain torque events?

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    Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
    10 minutes ago, northwestsnow said:

    What a brilliant post!

    Thanks Catacol :)

    Perhpas GFS may be calling this correctly if i'm reading you right..

    I think GFS in the extended may be doing a better job of reading the jet tilt...I'd certainly question the angle of atlantic attack present on the ECM at 216. There simply isnt the background forcing in the near term to justify a dig as steep as that. However I'd love to be proved wrong!

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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    The ECM ensembles are a touch disappointing for De Bilt which is a good indicator in these set ups.

    The op goes from one of the warmer runs for next Friday and Saturday to one of the coldest after that .

    So on one hand it’s possible the colder air could make more westwards progress upto that point but then too much energy might spill east rather than se.

    At least the uncertainty isn’t a case of one cold solution versus one mild mush one , but more a case of a battleground set up with possible slider versus a more PM flow type scenario .

    Hopefully we should know by tomorrow which trend is more likely to verify .

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    Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
    7 minutes ago, Catacol said:

    I think GFS in the extended may be doing a better job of reading the jet tilt...I'd certainly question the angle of atlantic attack present on the ECM at 216. There simply isnt the background forcing in the near term to justify a dig as steep as that. However I'd love to be proved wrong!

    How does ecm come with these solutions? These aam and mjo diagrams all seem to be based on the gfs, could it be the ecm is seeing something else? 

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    Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

    Had a good look through the past 6 ECM clusters including this mornings 00Z (not 12Z as not out yet)

    Very clear trends common to most clusters:

    D5-D8: Battle between heights to east / trough to west - not absolutely clear where the dividing line will be but probably not far from the UK

    D8-D11: Atlantic trough dives in a SE direction probably straight through the UK

    D12-D15: Azores high ridges in, introducing a WSW/SW flow to the UK for at least a day or two

    The two signals D8-D11 (15-18 Jan) and D12-D15 (19-22 Jan) are surprisingly clear! Basically, a big bite at the cherry D8-D11 especially for the north, and no instant second bite at the cherry shortly after.

    This also would mean tonight's ECM op is pretty much on the page with the ensemble trend right out to D10.

    The idea I had a couple of days ago about a northerly effectively binned :)

     

    Edited by Man With Beard
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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

    Seems to be a spate of wannabe mods on here tonight. 

    Anyway - ECM, UKMO and to an extent GFS ops still going for blocking but still little sign of any significant cold aside from the UKMO in FI which has the cold air fairly close to us.

    ECM whilst synoptically looks good, probably wouldn't produce anything away from the Northern hills. 

    I'm still really struggling to see where this bitter Easterly is going to come from, despite the small corrections on the OPs, there still isn't that much supporting it.

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    Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
    33 minutes ago, ArHu3 said:

    How does ecm come with these solutions? These aam and mjo diagrams all seem to be based on the gfs, could it be the ecm is seeing something else? 

    NCPB and ECMM are the 2 I use. Ensembles with tweaks. ECM is definitely in the suite.

    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

    Some excellent posts in this thread today - one of the best this winter I say. Models are trending more towards the trough edging the battle from the continental ridge, but a close call. Looking like we will see a very unsettled trough dominated set up mid January, prior to a possible much colder wintry locked in pattern to end the month thanks to background signals placing pressure on the PV as suggested by Catacol and others tonight.

    For those wanting cold easterlies may have stay patient they may well arrive before the month is out, before then, for those in the north at least every chance of some significant snowy episodes possible as we see low pressure sliding through the UK - similar to December, but perhaps on a more northerly path, which reduces the chances of snow in the south -but for all it is far from a mild zonal outlook, cold zonality indeed!

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    Posted
  • Location: Erith. SE London/kent 40m asl
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Erith. SE London/kent 40m asl

    Just noticed that the ICON is looking very good tonight out to T120, I wonder what the 18z will come up with? Could be some really cracking runs coming out in the next 24hrs.

    icon-0-120.png

    icon-1-120.png

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    Posted
  • Location: Skirlaugh, East Yorkshire
  • Location: Skirlaugh, East Yorkshire

    A few posts have been removed. If you feel a post is against the rules then by all means use the report button so we can take action.

    Thanks :)

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    Just now, Catacol said:

    Really? And there I was thinking I was answering a specific question. Nobody forced you to read it.

    Just one last thing (promise I wont bother anyone any more), not actually sure exactly what frictional torque (just seen it is a pre-cursor to mountain torque) is but presume its linked to the GWO and angular momentum (is it the frictional effect of wind against the earth surface?) - I  already know the very basics of MT, although cant remember which one is _+ and -, whether high pressure to the east of mountain trange or west.

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    Posted
  • Location: Wigan 259 ft ASL where it always rains
  • Location: Wigan 259 ft ASL where it always rains

    BBC going for a jet stream across the country at the end of the week with LPs attacking from the Atlantic , no indication of anything cold

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

    If it wasn't for that shortwave to the East of Iceland knackering it, this would have been a corking run.

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    Posted
  • Location: Bournville Birmingham
  • Weather Preferences: Hot n cold
  • Location: Bournville Birmingham
    2 minutes ago, Spurry said:

    BBC going for a jet stream across the country at the end of the week with LPs attacking from the Atlantic , no indication of anything cold

    Mr Hammond told me 'Give it time....'

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    Posted
  • Location: Bournville Birmingham
  • Weather Preferences: Hot n cold
  • Location: Bournville Birmingham
    1 minute ago, feb1991blizzard said:

    If it wasn't for that shortwave to the East of Iceland knackering it, this would have been a corking run.

    Which run?

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    1 minute ago, Sweatyman said:

    Which run?

    This one.

    EDIT : GFS

    Edited by feb1991blizzard
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    Posted
  • Location: Hoyland,barnsley,south yorkshire(100m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(100m asl)

    Well,the 18z is sinking this high quicker than the TITANIC,lets move on and have some interesting weather in the source of PM origines

    the 12z showed a pressure drop in Oslo and looks to drop further on the 18z.

    prmslOslo.png

     

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    Posted
  • Location: Sowerby Bridge, West Yorkshire
  • Weather Preferences: Click on my name - sorry, it was too long to fit here......
  • Location: Sowerby Bridge, West Yorkshire
    5 minutes ago, feb1991blizzard said:

    If it wasn't for that shortwave to the East of Iceland knackering it, this would have been a corking run.

    It's the one west of Iceland that concerns me, the more it sticks to the PV chunk the better but, this run, it's separated itself again. Still time for recovery but that could spoil any clear flow.

    Edited by ukpaul
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    Posted
  • Location: Bishops Cleeve, Cheltenham. 300 M ASL
  • Weather Preferences: Extremes, the very hot and the very cold.
  • Location: Bishops Cleeve, Cheltenham. 300 M ASL

    https://mobile.twitter.com/DrAHButler/status/950120680636538880/photo/1

    Looks like those zonal winds will be dropping considerably later this month. Ties is with GP, Tamara & Catacols ideas.

     

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    Posted
  • Location: Grimsby, North East Lincolnshire 16m asl
  • Location: Grimsby, North East Lincolnshire 16m asl
    1 minute ago, Sweatyman said:

    Mr Hammond told me 'Give it time....'

    Please can you explain. I have read the name Johm Hammond a few times on here today,  Are you referring to a well known weather presenter? If so what has he said? thanks?

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    Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

    Red herring springs to mind. This is a close but no nirvana moment - again! We are just too far west - again! The cold pool will make it to western Germany - again! But no further. This may seem a touch arrogant but they are my thoughts based on the current model projections. 

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