Jump to content
Cold?
Local
Radar
Snow?

Model Output Discussion - The Run In To Christmas


Recommended Posts

Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

    There we go one run with downgrades and this topic goes downhill in a matter of hours predictable really (not the runs but the uproar in here this afternoon), wait until ECM has finished and then make conclusions. Anyway, still looking good for Christmas and on wards in my opinion, we are in fantastic position compared to last year and also we still have ongoing wave activity and increased chance of SSW/Wave 2 Activity by turn of the year. So no complaining from me today.

    Yes but you can't expect the mood to be buoyant given the charts we were seeing yesterday. Most of the comments I have read have been entirely realistic, except for the few that are perhaps overreacting a tad!

    Even if the ecm throws out a stunner, there's reason to be concerned.

    Edited by CreweCold
    • Like 2
    Link to post
    Share on other sites
    Spotted a post you think may be an issue? Please help the team by reporting it.
    • Replies 1.8k
    • Created
    • Last Reply

    Top Posters In This Topic

    Top Posters In This Topic

    Popular Posts

    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

    Posted Images

    Posted
  • Location: Windsor
  • Weather Preferences: Snow and cold
  • Location: Windsor

    Regardless of whether GFS or GFSP is better in the overall scheme of things, the important point here is that GFSP stays in high res out to 240 hours (I think that's correct). It is the 180 to 240 bit that's important at the moment, so between 192 and 240 hours I'd be paying more heed to the GFSP (whilst still just noting the old GFS)

    All the models regardless of their resolution are likely to be miles off as the upcoming pattern change is so volatile. Currently FI is 96 hours.

    Link to post
    Share on other sites
    Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

    A major step back from Atlantic ridging on the whole GEFS suite and it does appear they have mis-read the signal in the previous  2-3 days:

     

    post-14819-0-22668200-1418923027_thumb.p

     

    The question is will the other models follow the GFS lead or is this just a wobble by the GFS?

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Springfield, Chelmsford, Essex 30Mtr ASL
  • Weather Preferences: snowy or sunny but not too hot!
  • Location: Springfield, Chelmsford, Essex 30Mtr ASL

    When there are major shifts between outputs run to run it generally means that the pattern is very volatile and could go one of several different ways which is why I don't take credence to individual runs and hence why I only commentate on one run a day (the 00zs). This eliminates any post stress that occurs after every 6 hour run doesn't show what was shown on the preceding one and gives the models a chance to iron out such swings into a more calculated 24 hour outcome. I admit day to day too provides some interesting comparisons at times usually when cold weather threatens the UK. Every brick has to fall in the correct place for the UK to receive the holy grail of snow and cold most want to see and there is a 90% chance of that not happening on an island such as ours lying on the Eastern end of a large Ocean as we do and with a usual prevailing Westerly wind across it . It only takes something seemingly quite small synoptically to move in a different way to expected to mean quite different results at the surface.

    Thanks for your reply,

     

    Much appreciated.

     

    Kind Regards

     

    Dave

    Link to post
    Share on other sites
    Posted
  • Location: London Waterloo 0m/ Leeds Bradford Airport 200m
  • Location: London Waterloo 0m/ Leeds Bradford Airport 200m

    Bin the GFS P 12z, a complete lack of consistency on the upper 500mb profiles across the North Atlantic/ North West Europe.

    A spell of colder weather is a definite across far northern areas of the uk as has always been the case, whether the shortwaves play ball is another story and one that won't be modelled consistently until 36-72 hours out.

    I think some are forgetting we are analysing output a good 6+ days a way, perhaps the more indepth view the GFS P poses

    Post T192 is throwing people of. FI is still T192 onwards and anything post T168 should be looked at in a broad sense, essentially if we retain heights in the North Atlantic then parts of the UK will see colder weather. There has always been a caveat for southern England as shortwaves are unlikely to deliver.

    Edited by Cheese Rice
    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

    There we go one run with downgrades and this topic goes downhill in a matter of hours predictable really (not the runs but the uproar in here this afternoon), wait until ECM has finished and then make conclusions. Anyway, still looking good for Christmas and on wards in my opinion, we are in fantastic position compared to last year and also we still have ongoing wave activity and increased chance of SSW/Wave 2 Activity by turn of the year. So no complaining from me today. 

     

    well actually it wasnt one run, as the past two (at least) were a downgrade of the severity of the cold the gfs suggested previously. so the short term trend is away from the colder option and the ecm was never really on board. i dont expect much change from the ecm, but itll be 'better' for cold lovers then the gfs 12z.

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    Looking at GFS P the vast majority see temps no higher than 4c on Xmas day

     

    168-582PUK.GIF?18-12

     

    Similar story for Boxing day

     

    192-582PUK.GIF?18-12

     

    Snow for parts of Scotland

     

    192-779PUK.GIF?18-12192-780PUK.GIF?18-12

     

    One more cold day on the 27th though a lot milder in the far west, snow on the leading edge in the east and Scotland

     

    216-582PUK.GIF?18-12216-779PUK.GIF?18-12216-780PUK.GIF?18-12

     

    Milder for most by the 28th with some rain around

     

    240-582PUK.GIF?18-12240-779PUK.GIF?18-12

     

    What I'm seeing is a chilly Christmas with some snow around in the north mainly to high ground initially then maybe becoming milder W/C 28th which ties in well with today's met office update

    Edited by Summer Sun
    • Like 4
    Link to post
    Share on other sites
    Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

    How do you like your Christmas weather? All are catered for within GFS ensembles.

     

    gensnh-1-1-174.png?12gensnh-11-1-174.png?12gensnh-12-1-174.png?12

     

    Signal for Xmas day Northerly very muted in 12z ensembles.

     

    graphe3_1000_255_103___.gif

     

    But most importantly a very obvious split developing with 2 distinct clusters milder/colder from day 5.

    Which will we get?

    Edited by Mucka
    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Coney Hall Village 260ft asl, North West Kent
  • Location: Coney Hall Village 260ft asl, North West Kent

    Viewing the output this evening, one gets the impression this has come too early in terms of stratospheric state. It's just not conducive enough for HLB establishment yet. It's extremely frustrating watching the stubbornness of the vortex this year given on the face of it it has little working for it!

    It's always just one more blow away from being taken out but then inexplicably stumbles back to its feet.

    I believe there is ongoing interest in the strat thread re the life / future state of the P vortex CC

     

    https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/page-40

    Edited by Biggin
    Link to post
    Share on other sites
    Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

    There are 3 current predicted tracks for our problem shortwave

     

    Once it in the central atlantic it can

     

    Recurve NE over the UK- worst case scenario - GFS

    Recurve ESE over the UK whilst pressure builds north - GEM

    Recurve NW & pressure builds behind it-

     

    Interestingly conditions are VERY favourable for Greenland high pressure as long as the shortwave doesn't get bent NNE to the North of the UK.

     

    The GFS is a total mess, the high entropy starts around 120

     

    S

    It all boils down to that shortwave Steve. Comes out of nowhere at the worst possible time (as ever) and you really couldn't make it up.

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

    Like a few other more seasoned model-watchers have stated, let us not jump to conclusions about the big day itself yet as it is still some seven (7) days away. Having said that, I've consistently favoured a colder period post Xmas itself, more especially if you live in my region of the UK. I've highlighted Boxing Day before as a date by which I expect colder uppers and snow-producing synoptics to show up more readily, well take a look at this.

     

     

    post-7183-0-89130700-1418923641_thumb.pn

     

    The UK broadly is under the -4c to -12c uppers range on the above chart. Yet, even then its at t+195 hours right now so could upgrade or downgrade.

     

    I suspect the general synoptic pattern for my patch is getting nearer the mark as I feel Christmas Day will be a drier day with largely an HP dominated pattern, so looking like a nice crisp, cool to cold day for most. A chance for a countryside walk or pleasant walk to the local by then, I would reckon. 

     

    The general broader weather pattern looking like this for Boxing Day afternoon, again according to today's 12z GFS P

     

    post-7183-0-49085000-1418923641_thumb.pn

     

     

    24 hours earlier, Christmas Day perhaps looking something similar to the chart below.

     

    post-7183-0-98248300-1418923640_thumb.pn

     

     

    Plenty of positives to note, ongoing building heights over Greenland, associated WAA across that region too. Added to that, a decent setup ongoing up in the 10hpa region of the stratosphere as illustrated below for 1500hrs on Christmas Day.

     

    post-7183-0-63150400-1418923640_thumb.pn

     

     

    • All in all, a far removed weather pattern from last Christmas and its horrid Winter and any further confidence in the forecast will continue to grow, once other runs back up and perhaps play catch up nearer the date. I have a feeling the Countryfile forecast will be the mostly hotly anticipated forecast of the year. My current bet (not having one as I've punted on the darts) is that there is a very small chance of snow up North on Christmas Day but a much greater chance of more widespread snow as we head nearer the turn of the year.   :smiliz19: 

     

     

    More runs are needed and patience remains a virtue for the big day itself and beyond.  :friends:

     

    PS keep a close eye on where the NE USA depression currently forecast by 0000hrs Saturday due south of Greenland tracks to, beyond the weekend as this will be key to specific developments further on. I don't trust how the GFS 12z handled it but of course it could be right, if it behaved as previously modelled, I would suggest the Christmas Day/Boxing Day setup would be snowier.

    Edited by gottolovethisweather
    • Like 5
    Link to post
    Share on other sites
    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    Exactly. I always use the notion that they have 6 hours of new data....what went before is history and holds less weight than the most recent model runs. We can't brush these things under the table but equally we can't draw firm conclusions.

     

    That is only true for fairly close days ahead, say out to 144h beyond that and increasingly the further out you get then using the same run for the same time ahead ie, 216h then 192 h etc will get a more reliable result on most occasions. Something I proved about 10 years ago and I doubt that the validity has changed.

    Link to post
    Share on other sites
    Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

    Rewind 12 months to the rotton to the core winter of 2013 / 14 ...now flash forward to the present and you will see what progress we have made apart from the current mild mush, the outlook is a lot whiter. :-)

    Edited by Frosty.
    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

    Rewind 12 months to the rotton to the core winter of 2013 / 14 ...now flash forward to the present and you will see what progress we have made apart from the current mild mush, the outlook is a lot whiter. :-)

    The irony is if the GFS 12z was correct then this December might actually come out milder than last year  :rofl:

    Dear oh dear, we have come to the point now where we could still get a prolonged spell of cold weather, or indeed get nothing (that includes the cooler days which were agreed on for Christmas Eve/day).

    How that low in the central Atlantic develops and interacts with the ridging around it will determine when and where it will move. This will take a couple more days to resolve.

    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

    The irony is if the GFS 12z was correct then this December might actually come out milder than last year :rofl:

    Dear oh dear, we have come to the point now where we could still get a prolonged spell of cold weather, or indeed get nothing (that includes the cooler days which were agreed on for Christmas Eve/day).

    How that low in the central Atlantic develops and interacts with the ridging around it will determine when and where it will move. This will take a couple more days to resolve.

    I was just going to reply to Frosty saying exactly the same thing! Wider NH synoptics mean zilch if the weather on the ground here isn't benefitted by them!

    It's like your wife treating herself to some new sexy lingerie, only to find out they're for the benefit of another fella.

    Edited by CreweCold
    • Like 8
    Link to post
    Share on other sites
    Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

    The alarm bells rang for me yesterday when I saw the flatter pattern develop from the Canadian trough in the ECM suite.

    The weaker Alaskan ridging is the source of the problem and this works it way into seeing less amplification of the Atlantic around Christmas.

    http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=168&mode=0&carte=1

    Without that substantial Greenland ridging the cold air can't drive south over the UK and this leaves the Euro heights closer.

    Not a trend we wanted to see and the hope is there are more warmings to come for another re jig of the pattern.

    • Like 4
    Link to post
    Share on other sites
    Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

    The irony is if the GFS 12z was correct then this December might actually come out milder than last year  :rofl:

    Dear oh dear, we have come to the point now where we could still get a prolonged spell of cold weather, or indeed get nothing (that includes the cooler days which were agreed on for Christmas Eve/day).

    How that low in the central Atlantic develops and interacts with the ridging around it will determine when and where it will move. This will take a couple more days to resolve.

     

    Currently near average at my house, with a departure from the norm of +0.2c, would take something special, well horrific perhaps to reach the 0.7c warmer than average December and the bucket loads of rain that ruined so many folks Christmases too.

     

    1330.png and cheese_oh_cheese.jpg

     

    A lot of overanalysis on both sides of the debate in here tonight and at this stage, I would probably favour a colder scenario for most with maybe one or two milder nights and days thrown in across the final third of December. Truth be told we're all second-guessing really but that is simply part of the fun.  :w00t:

    Edited by gottolovethisweather
    • Like 5
    Link to post
    Share on other sites
    Posted
  • Location: Oldbury, West midlands
  • Weather Preferences: Heavy snow, Thunder storms and lightning
  • Location: Oldbury, West midlands

    We might not like it but we have to give credit to the ecm for spotting the shortwave first, I am sure it also did the same last year those shortwaves are becoming a real pain in our winters, let's hope the ecm spots another trend and burries that shortwave so we can all get back to good spirits in here, does anyone have the information if one those shortwaves popped up in 2010 and gave the same headaches the models and forecasters are having now or was it a much more smoother transition

    Link to post
    Share on other sites
    Posted
  • Location: west yorkshire
  • Weather Preferences: extreme weather
  • Location: west yorkshire

    Even if the xmas cold blast fails to deliver it's not end of world. We have wave 1 & 2 activity happening a ssw warming looking more and more likely. And I think not long into new year till we see some stunning charts. Lots of winter to come yet guys.

    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

    I was just going to reply to Frosty saying exactly the same thing! Wider NH synoptics mean zilch if the weather on the ground here isn't benefitted by them!

    It's like your wife treating herself to some new sexy lingerie, only to find out they're for the benefit of another fella.

     

    Conversely we could have a powerful PV stuck in residency over "you know where" and a raging Jetstream bringing endless depressions under a SWr'ly flow and yet the NWP outputs aren't forecasting either.  :sorry:

     

    A la 2013-2014.jpg

    Edited by gottolovethisweather
    • Like 3
    Link to post
    Share on other sites
    Guest
    This topic is now closed to further replies.
    ×
    ×
    • Create New...