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Hunt For Cold: Model Discussion - Heading Into Christmas


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Last one from me for 6 weeks before I leave in the morning for Canada . Our experts we use in resort have told me that todays upper air soundings over the Russian Arctic are showing Easterlies now est

After a health scare I have had the best news ever and been given the all clear. What a year it has been weather wise.Just like to take the opportunity to wish Paul,all The moderating team a

Afternoon so 2 hours on the train should be plenty of time for a post- The last 2 weeks the projected SSW has gradually worked through the models & is now 'imminent' ~ 30hours away is when we

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Posted
  • Location: Loggerheads, Staffs
  • Weather Preferences: Hot and sunny summers, cold & snowy winters
  • Location: Loggerheads, Staffs
    30 minutes ago, karyo said:

    We can 'thank' the Alps for that.

    How so? Is it related to Foehn effect?

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  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
    2 hours ago, weirpig said:

    Wonderful Strat profile on the Para    Total Split   one side over above Canada which should stop anything becoming west based   and a additional warming at the end of the run.    Middle of January could well be fun 

    would bring some serious cold my way...talking -30c to -40c right at the coldest time of the year.

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    Posted
  • Location: Co Dublin, Ireland
  • Location: Co Dublin, Ireland

    icon-0-180.png?21-12

     

     

    ICON

    Synoptically analogues of what we see at the moment progged for the forseeable are probably the winters of 97 - 00. That's the closest I can think of certainly for the next 2 weeks as things stand.

     

     

     

     

     

     

     

     

    Edited by The Eagle
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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Not a great deal of excitement to be had for the next ten days given recent op runs .

    Just perhaps a small chance of something colder around day 7 and 8 ,  at the moment the upstream pattern over the USA is flat however some amplification is likely to work east as a Pacific shortwave develops as it runs towards the Great Lakes.

    Ahead of this a Canadian high will develop , this will slow down the Atlantic . Depending on how much dig south we see in the troughing in the west Atlantic this may allow some cut back in the jet to the east .

    The MJO forecast has improved today esp in the GFS which has a more coherent signal and eventually this moves in towards phase 6 .

    Theres still a lot of scatter in the ECM ensembles but the NCEP monthly update does suggest the MJO should continue to move towards the more favourable phases over the next few weeks .

    Edited by nick sussex
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    Posted
  • Location: East Ham, London
  • Location: East Ham, London

    Afternoon all ?

    As usual, those wanting snow, ice and -20 uppers are complaining because there's nothing showing in the next 7-10 days. 

    True and it looks a remarkably benign Christmas and New Year period for most which is no bad thing for those having to travel and visit their families and/or loved ones.

    The signals for something of more interest in the early to middle part of January remain there - the 06Z Parallel was a thing of beauty in far FI and interesting to see both Control and OP toying with slowing the Atlantic to a crawl and rising pressure over to the NE of the British Isles. GEM 00Z looks more like an inflated ridge from the UK and that's ten days out.

    The first HP for Christmas won't be strong enough to ridge NE combined with too much residual energy in the jet so it slides ESE but a second burst of HP at New Year looks more promising but nothing is settled. The 06Z GEFS does indicate more members taking the core of the HP to the north which may be good for cold fans but there's no snow in many of the members at this time. 

    It's a three phase process I think - the HP moves up from the south, transfers north or north east and later retrogresses. Ideally, we'd need a nice cool down before we get the easterly and then the northerly and then back to an ESE as the Atlantic tries to come back in from the SW. That's a 7-14 day severe cold spell for mid January (or maybe later).

    The split PV continues to be modelled on the Parallel if not the OP with the split coming on January 2nd and indeed the 06Z Parallel initiates another burst of warming on the shattered PV which would pretty much finish it off. Even the OP weakens the PV significantly from what we would expect in January but it is a displacement not a full split. That said, even a displaced vortex offers opportunities for cold.

     

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    Posted
  • Location: East Ham, London
  • Location: East Ham, London
    4 minutes ago, mountain shadow said:

    UKMO flat as a pancake but only goes out to Day 6 so not really concerned.

    image.thumb.png.9f084ba820801d61898d4a84fca612b2.png

    First, it isn't flat but yes, the first build of HP is declining SE and the second, more substantial build is coming NE from the Azores and Iberia. There's also a good sign the Atlantic is slowing and weakening on the UKMO as well which we also need to see.

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  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level

    Im watching the GFS 12z strat-wise and i have a feeling (only out to 210) that this run will be the one that breaks the mould!!

    Just watch it build a raging PV at the end lol..

     

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  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    So far, the 12Z is about as exciting as the three-thousandth remake of Pride and Prejudice!

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    Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

    diagram_40days_forecast_GEFS_member.gif

    Well this is actually hilarious. From crawling along at low amp in P5 to roaring through to P6 in the space of 24 hours.

    ECMF_phase_51m_small.gif

    ECM's also adjusted faster and more amplified but in a much less frantic manner. It often comes around more slowly but steadily at times like this.

     

    This should have the effect of promoting more NW extension of ridges from the UK past +7 days range, provided the operational models follow their ensembles with this trend.

    Regardless of what they get up to this evening and tomorrow for that matter, this development is in line with anticipations and suggests we truly are on the golden path to a tropical-stratosphere co-operation with respect to bringing 'proper winter' to our shores next month.

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    Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
    5 minutes ago, northwestsnow said:

    Im watching the GFS 12z strat-wise and i have a feeling (only out to 210) that this run will be the one that breaks the mould!!

    Just watch it build a raging PV at the end lol..

     

    Split start a week on Sunday, will we see a trop response by the end of the run?

    image.thumb.png.9850e889b6e00164aa8516caac89cce3.png

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  • Location: Loughmacrory, Co Tyrone. 170m asl
  • Weather Preferences: snow
  • Location: Loughmacrory, Co Tyrone. 170m asl

    Check out @judah47’s Tweet:

    Total novice here but this looks good from Dr Cohen. Am I right in thinking this backs up what a lot of you guys have been saying about GFS being a dud strat model?

     

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  • Location: Newhey, Lancashire ( 165m a/s/l )
  • Weather Preferences: Snow
  • Location: Newhey, Lancashire ( 165m a/s/l )
    A tweet from Mr Hugo
     
    A simple observation. The UKMO model has been as much use as a chocolate fireguard of late. Hell it's having a rough week. Absolute pile'o dung... ICON consistent regarding the colder, sunnier Christmas. GFS, like usual all over the place like it's had too much sherry too.
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  • Location: Manchester
  • Location: Manchester
    14 minutes ago, northwestsnow said:

    Im watching the GFS 12z strat-wise and i have a feeling (only out to 210) that this run will be the one that breaks the mould!!

    Just watch it build a raging PV at the end lol..

     

    Out to 300 hours is a small improvement to the 6z but still not the perfect split.

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  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    3 minutes ago, karyo said:

    Out to 300 hours is a small improvement to the 6z but still not the perfect split.

    Agreed, its better, and does show a split of sorts..but your right, its not great..

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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    3 minutes ago, Glacier Point said:

    NH_HGT_50mb_360.thumb.gif.79b14e59546a5ac83c05a99e3bfff931.gif

    Take a look further down. 12z op likely to be a significant outlier synoptically in our quadrant based on this.

    Yes, will watch the Para to see if there is a difference-FWIW Stewart does this recently released tweet match your thoughts perhaps?

    W COUNTRY: By Christmas Day & into early Jan, high pressure is set to dominate UK weather (ECMWF shown for 30/12, high cell position not to be taken literally!). However, this is likely to shift to Scandinavia further into Jan, with increasing risk of cold by mid-Jan on into Feb

    Fergie this afternoon..

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  • Location: uxbridge middlesex(south east england)
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(south east england)
    11 minutes ago, Glacier Point said:

    NH_HGT_50mb_360.thumb.gif.79b14e59546a5ac83c05a99e3bfff931.gif

    Take a look further down. 12z op likely to be a significant outlier synoptically in our quadrant based on this. Placement of the vortex west of Greenland the vital thing here. GFS likely to have it too far east and north here.

    Gfs has missed the sway..and imo the modeled vortex placements 'alone'..are of-mysterious miss modeling!!!

     

    Edited by tight isobar
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    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    If the 12Z is anything to go by, the Para can only be an improvement?? Is there such a thing as an Extra Slow Tropospheric Response (ESTR)?

    Netweather GFS Image

     

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    Posted
  • Location: Brighton, East Sussex
  • Location: Brighton, East Sussex

    Look at the stamps the crucial timeframe seems to be circa day 8 or 9 when the strongest segment of the PV over the pole and Greenland area starts to make a move, you only need to glance at the plethora of options amongst the ensembles to see that as of yet what happens to the vortex is a real guessing game.

     

    There’s certainly something going on CIRCA day 10 because the vortex is being shredded by blocking all over the globe. ? 

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

    Amazing consistency from the models in the medium term so high confidence remains up to D10.

    EDH1-240.thumb.gif.ffd2f4049c475b0eae870682fcff2677.gif1229459352_gfsnh-0-240(1).thumb.png.0f8755f68c9c88f2bbd383d909a76a14.pnggemnh-0-240.thumb.png.a00732c0ea4bcbf4218456bbd5678340.pnggensnh-21-1-240.thumb.png.b3a65102457e1dc82c55be73ee0078e6.png

    As the experts keep saying, mid-Jan onwards for definitive changes, till then HP UK domination! After D10 expecting trop led changes and hopefully a more meridional flow for when we get any strat downwelling. Of course, we are now getting to the timeline where we could see the models flip to something interesting within a short period of time so interesting times just around the corner!

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    Message added by Paul

    If you're hunting for cold potential in the model output, this thread is for you. But if you'd like to look more widely at the models, please head over to the general model discussion thread.

    This is a model related thread, so a general, frequent theme of the model output is a given, but it will not be strictly enforced:

    • Some topic drift, humorous responses etc are fine
    • Posts likely to lead the thread off on an entirely off topic tangent are not ok. For example (but not solely limited to): Posts entirely or mainly about Met Office, BBC or media forecasts with little or no model context, and posts solely asking for a weather forecast in a specific location.
    • Posts which start with something like 'I know this is off topic but ...' are not ok.
    • Posts which break the forum guidelines are not ok (eg trolling, troll-hunting, weather guilt tripping, overly defensive/aggressive, abusive, disrespectful to others)
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