Jump to content
Cold?
Local
Radar
Snow?

Model Output Discussion - The Run In To Christmas


Recommended Posts

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: Mile Oak, 3 miles West of Brighton UK, 130 Meters above sea level
  • Weather Preferences: Anything Extreme
  • Location: Mile Oak, 3 miles West of Brighton UK, 130 Meters above sea level

    If you run through the various outputs on the 06z you'll see that the reliable time frame sits about about 3 days out right now. 

     

    Some runs keep that low pressure system well away from the UK, some don't develop it at all, some have it running through Iceland, some to the South of the UK, I expect if it does develop it will take the normal route through N.Ireland and into Scotland and the reset westerly bore fest would soon follow. 

     

    IMO this will be a bog standard winter storm and by the new year we'll all be looking for the next opportunity for things to go our way. 

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Irlam
  • Location: Irlam

    GFSp: If the snow storm on 27 Dec does look on I say bring it on. There is nothing more annoying on this forum than people saying "be careful what you wish for, people are travelling" - of course the weather will do what it will do and in any event people wouldn't travel if that bad boy was forecast at T12hrs.

    If you are hoping a snowstorm on that GFSp run, you maybe disappointed because although it does show some snow as the colder uppers dig in, they are mixed out pretty quickly. It could a cold very breezy wet affair in the end. At least on that GFSp 06z run and at lower levels.

    Edited by Weather-history
    Link to post
    Share on other sites
    Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

    I have to say with regards to the possible storm, I am more concerned with the wind strength than snowfall. At the moment it appears most of the precip would of cleared the UK by the time it is cold enough for snow. Also the models hints at a NE,ly and the warming effects of the N Sea would reduce the chance of snowfall even further for E areas. Obviously the track will make a difference but at this stage only higher ground appears at risk.

     

    Moving further on and I cannot see mild returning beyond the storm. I said there is a chance of it turning much colder from the E towards the New year and I continue to believe this.

     

    I don't often predict an E,ly :cold::shok:

    I can't see an easterly developing after the storm. A transient north easterly (a blink and miss it affair) as the storm sinks south east

    quickly followed by toppling ridge and the northern arm re strengthening over the top.

    On a side note, something at ECM headquarters needs to be discussed with that particular model's propensity to

    blow up heights to our north west. It is a real big problem for the model (both ops & ensembles) and has been for quite a few years.

    It causes a hell of a lot of frustration in here, I know that much.

    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

    Can you post a chart / model that is showing a "Snow storm" ? GFSp is the closest I have seen but it shows sleet or rain for 90% of the uk population. It was always looking like a slim chance for the south or low ground to see snow but now only tops of Pennines etc and Scottish mountains see a decent dump. I'm praying last nights ECM resurfaces!

     

    Yes despite the more amplified 06z run the chances of snow in the south from the ensembles remain about 10%: 

     

    post-14819-0-59465500-1419161075_thumb.g

     

    About 50% of the ensembles support the cyclogenesis of the LP system and its track to sink SE/S and that includes the C:

     

    post-14819-0-84253000-1419161149_thumb.p  post-14819-0-46179800-1419161230_thumb.p

     

    With such a deep storm it is likely that it will not have cold enough uppers for snow for most.

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: st albans
  • Location: st albans

    I didn't post that spread chart this morning with this in mind but perhaps if might be interesting to keep posting the timeframe until we see the spreads fall to a level where we can have some confidence in the subsequent pattern

    Newest one first

    post-6981-0-06389700-1419161435_thumb.jp

    post-6981-0-66213300-1419161422_thumb.jp

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

    Really disappointed with the models these last couple of days with the way they have downgraded the potential

    cold as we approach New Year. The worst thing about them at the moment is that they do not even show any

    rainbows for us to chase in the long term. I know these rainbows are generally false dawns but at least they

    give us something to talk about. I guess all we can hope for is some sort of flip in the models for late next

    week. Clutching at straws though I certainly am.

    • Like 1
    Link to post
    Share on other sites

    Yes despite the more amplified 06z run the chances of snow in the south from the ensembles remain about 10%: 

     

    attachicon.gifgraphe4_1000_306_141___Londres.gif

     

    About 50% of the ensembles support the cyclogenesis of the LP system and its track to sink SE/S and that includes the C:

     

    attachicon.gifgens-0-1-150.png  attachicon.gifgens-0-0-150.png

     

    With such a deep storm it is likely that it will not have cold enough uppers for snow for most.

     

    And yet on some models (GFS normal) 850Hpa uppers of -8c are forecast for Wales with NW winds giving the chance of wintry/snow streamers from the North west.

     

    post-213-0-83438600-1419161942_thumb.png

     

    Even on the 06Hz(P) which does mix the uppers there is the chance of some front edge snow. (sub -6c for a time)

     

    post-213-0-79504200-1419162405_thumb.gif

     

    I do think though that deeper the low pressure the lower the chance of more general snow and the above run (normal GFS) makes less of the LP system hence colder uppers.

     

    If the current models are close to fruition, it is difficult enough to model at 24 hours, let alone 144 hours.

     

    Edited by J10
    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.

    To my eyes the various NWP outputs are now suggesting a mostly quiet picture as we head towards the New Year with HP influence never far away. Get the next couple of days nuisance rainbands out of the way and we should have a settled calmer picture for all come Christmas Eve through to Boxing Day. As mentioned by many more of the seasoned forum posters and by myself here for instance, the 27th and 28th December are dates to watch. During this timescale, the current modelling suites all suggest that this could be a potential game-changing Low Pressure system, which as it pushes over our shores, it is likely to bring much rain and perhaps back-edge snow for a lucky few and more appropriately a gale to severe gale to some parts. Why a game-changer, you ask?

     

    Well, heights are over Europe are stubborningly High up to then and this is never a good sign for coldies, wanting deep cold. As the depression is currently forecast to dive into Central Europe as we near the year-end, we will end up with colder air following up behind it, affecting us and also the nearby continent. This new found weather setup could well persist into the New Year in my opinion and is our best shot at cold over the next two weeks. More widely, the positives continue to be the brief pulses of  WAA pushing up towards Greenland and Iceland and added to this, a confused much weakened NH Jetstream compared to this time last year and is shown to produce a split flow at times too. The Atlantic fronts should be held at bay as we end the year too as the stubborn troughing signal has seemingly relented for now, we can and should get a very different setup in place. Mild at times at the surface then nearer Average over Christmas and a most likely colder scenario to end the year is how I view things right now.

    Edited by gottolovethisweather
    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

    Looking at the Ens, factor in what is likely to occur in the States and you can see how zonal Atlantic driven weather may actually now be the favourite outcome as we head into the New Year. FAR from set in stone though. Plenty of water to get under plenty of bridges before we start getting too confident on that score! Personally I think we are heading, with blips, towards a decent cold spell in the new year

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: ipswich <east near the a14> east weather watch
  • Location: ipswich <east near the a14> east weather watch

    http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

     

    well after  the  storm things  are  now looking much    better  for  cold  weather in the new  year  could easily  bring  snow to the  u.k.  just  in time  for  the  rush   hour  back  to work on jan  5 :smiliz64: :cold: !!

    Edited by tinybill
    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: The Purbeck Microclimate, Dorset.
  • Weather Preferences: Gales, T-storms, Heavy Rain, Heat, Cold - Love it all.
  • Location: The Purbeck Microclimate, Dorset.

    If you run through the various outputs on the 06z you'll see that the reliable time frame sits about about 3 days out right now.

    Some runs keep that low pressure system well away from the UK, some don't develop it at all, some have it running through Iceland, some to the South of the UK, I expect if it does develop it will take the normal route through N.Ireland and into Scotland and the reset westerly bore fest would soon follow.

    IMO this will be a bog standard winter storm and by the new year we'll all be looking for the next opportunity for things to go our way.

    Quite a few solutions have the pressure dropping some 30mb+ in under 24 hours, I'd say that's a bit more than a bog standard storm!

    Disclaimer: I know it's the GFS op run but it's just an example.

    1010mb to 976mb in under 24 hours..

    post-15177-0-08235900-1419162859_thumb.ppost-15177-0-58590800-1419162870_thumb.p

    That one of a few extreme solutions, I'm sure!

    Anything involving cyclogenesis on that level will be above your average storm, and looking at it across the board, I'm not surprised the guys at Exeter are watching this with a keen eye.

    Edited by Mapantz
    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Everyone knows by now I'm not quiet in displaying irritation at the outputs, however before this thread becomes too negative I think we need to just be a little patient but at the same time realistic.

     

    It's best to work from the premise that we won't be seeing a Greenland block, the conditions at present don't support a proper high there.

     

    The trend from the models is to take lower heights back across Greenland later on, there are timing differences with how quickly this occurs.

     

    So I think its best to kick into touch a long lasting northerly however within the scope of whats on offer and realistically possible there are still some decent solutions in terms of a spell of colder weather.

     

    It might be less snow and drier colder weather, it might also be a short northerly followed by an east/ne flow as the low slips into the Continent then high pressure close by and frost and fog type scenario, of course it could be short northerly then the high slipping much further south.

     

    Much depends really on the movement of those low heights eastwards and also whether the jet digs south off the eastern USA which would of course help to keep things colder.

     

    Low heights to the nw aren't always disastrous for cold but its really at this point whether the jet kicks ne with some energy going se to help keep the high in a colder position.

     

    There are still disagreements between the outputs from an early timeframe, upstream regarding a shortwave over the USA, in the mid Atlantic with another shortwave.

     

    We have to remember that the GEFS and ECM ensembles will include solutions that are completely wrong because what happens between T120 and T144hrs in both those key areas results in some larger scale changes further on.

     

    For example the GEFS if the ensembles have got that crucial shortwave wrong at T120 to T144hrs over the USA then this changes downstream events.

     

    Perhaps not enough to deliver some snow nirvana but enough to make a difference to the block and longevity of cold.

     

    So until we see agreement at those timeframes then the outlook still has a level of uncertainty.

    • Like 5
    Link to post
    Share on other sites
    Posted
  • Location: st albans
  • Location: st albans

    Great post muffelchen but i'm not sure where renewed hope came from this morning ...... Yesterday's 12z runs were the last high point and it currently looks doubtful there will be more for another week.

    Just read that post kris and I've been wondering about Scandi height rises - however, there has been no convincing wxtended ens evidence. Hints but no more than that.

    Edited by bluearmy
    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: Mile Oak, 3 miles West of Brighton UK, 130 Meters above sea level
  • Weather Preferences: Anything Extreme
  • Location: Mile Oak, 3 miles West of Brighton UK, 130 Meters above sea level

    Quite a few solutions have the pressure dropping some 30mb+ in under 24 hours, I'd say that's a bit more than a bog standard storm!

    Disclaimer: I know it's the GFS op run but it's just an example.

    1010mb to 976mb in under 24 hours..

    attachicon.gifviewimage (17).pngattachicon.gifviewimage (18).png

    That one of a few extreme solutions, I'm sure!

    Anything involving cyclogenesis on that level will be above your average storm, and looking at it across the board, I'm not surprised the guys at Exeter are watching this with a keen eye.

     

    Yes the Op and a few other runs have this system filling and deepening as it crosses the uk. 

     

    And if it came off like that then yes it wouldn't be a bog standard winter storm, I wasn't commenting on what the OP was showing, as I don't believe it will come off as modeled by the OP. 

     

    If I had to pick a run to highlight my point, then try this one (just as one example of many on the 06z)

     

    As I said...a bog standard winter storm...

     

    gens-7-1-138.png?6

    Link to post
    Share on other sites
    Posted
  • Location: leicester
  • Location: leicester

    Referring to the spreads bluearmy! ! What about the low confidence spread thats across england at that time (138 hours)!! Does that suggest any shortwave may take a different path to what it shows now?

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Beverley, E Yorks, 19m ASL
  • Weather Preferences: Snow, Thunder - not necessarily at the same time!
  • Location: Beverley, E Yorks, 19m ASL

    Great post muffelchen but i'm not sure where renewed hope came from this morning ...... Yesterday's 12z runs were the last high point and it currently looks doubtful there will be more for another week.

    Sadly I think you may be right but it was TEITS and his 'Beast' that I was referring to here as well as Nick's shortwave drama. Both of these could well fall right for us but, if truth be known, we kinda know that this probably won't happen. In truth, after a great start last October, this winter has disappointed in spite of the potential.  Even though I hardly ever post in here, I avidly read pretty much everything that is written and have been doing so for the last 8 years or so. My view is, sadly that I think the opportunities have been lost and we may get a bit of snow prior to a toppler or two over the winter, which is quite normal here, but I am of the opinion that the Strat warming will continue to be postponed, the MJO will never quite make it to phases 7 and 8 and real heights will never arrive in Greeny. As I said; missed opportunities...

     

    My gut feeling is this will be a winter of near-misses: we will run out of time before things finally fall into place. The weather is in a pattern that will need some shifting and, by the time ten more days have gone by, we will only have six weeks left of winter. After that longer days and increasing sun heights tend to make any snow cover transient.

     

    So, as ever, I will live in hope but I expect to be disappointed this time around.

    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: Freshwater Isle of Wight
  • Location: Freshwater Isle of Wight

    Perhaps we should be looking NE in to the 10-15 day period....

     

    attachicon.gifscandihigh1.gifattachicon.gifscandihigh2.gif

     

    Split vortex and ridging tendency heading more and more towards Scandinavia over the last couple of runs

     

    SK

    There was a chap I used to know that made a forecast for the week ahead solely from the 100mb actual charts. I cannot remember if his forecasts were accurate but he was well respected so they may well have given a good steer. The scandihigh2 chart might well give potential for cold from the east if it were to verify.  

    • Like 1
    Link to post
    Share on other sites
    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

    Perhaps we should be looking NE in to the 10-15 day period....

     

    attachicon.gifscandihigh1.gifattachicon.gifscandihigh2.gif

     

    Split vortex and ridging tendency heading more and more towards Scandinavia over the last couple of runs

     

    SK

     

    Yes, I'm perplexed as to the modelling of the Canadian vortex lobe now, just what on earth is going on there to keep it in situ come hell or high water? With the strat in the weakened state that it is, and likely to remain so if the current elongated and suggested subsequent warmings transpire and range over the whole strat, then the likelihood of heights rising over Scandinavia becomes almost inevitable.

     

    Can anyone explain why the Canadian lobe is, at the moment, seemingly immovable? 

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

    As much as some may like the GFS 06z in FI, it is the 06z so anything after D6 is JFF. Looking at the op, as usual it is an outlier in FI: 

     

    post-14819-0-56315800-1419164568_thumb.g Dutch graph more obvious: post-14819-0-49137100-1419164920_thumb.g

     

    The D16 mean is similar to the 0z and remains zonal: post-14819-0-95371300-1419164596_thumb.p

     

     

     

     

     

     

    Edited by i'm dreaming of...
    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl

    It's been a long while since I can remember so many days of sustained model disagreement, and inability to get a hold on the hemispheric pattern. The last few days have seen all sorts of variations - not just on a theme, but on the theme or "pattern" itself. Note these differences this morning... GFSP at 192

     

    gfsnh-0-192.png?6

     

    and then ECM for the same timeframe

     

    ECH1-192.GIF?21-12

     

    It's like looking at 2 different worlds, bar the signal for high pressure close to the UK. European heights different, EPO ridge different, location of most vortex energy different.

     

    Frankly I dont trust anything I'm seeing at the moment. One thing is sure though - we have a pretty major wave 1 assault on the vortex underway now

     

    ecmwfzm_ha1_f192.gif

     

    But we also have strat remperatures at the pole running well below normal after a dramatic reverse earlier in December:

     

    pole30_nh.gif

     

    ... and as a result a vortex that is stronger at its core than we expected it would be, leading to an ensemble mean forecast for 3-4 weeks time from JMA that looks like this:

     

    Y201412.D1712.png

     

    I know that Chio is still pretty bullish on twitter about the strat forecasts, but from my more inexperienced angle we seem to be placing a lot of faith in the current wave 1 attack displacing the vortex in such a manner that it will allow heights to rise over Greenland and a consequent wave 2 attack shortly thereafter. Trouble is - the images I'm seeing this morning are not showing a consistent signal for proper height rises over Greenland, and NCEP forecast for the lower strat like this one suggest that low pressure in the atlantic will remain with us, with heights if anything sitting more over the UK in a dull omega block.

     

    gfs_z100_nh_f192.gif

     

     

    So - conclusion? The models are all over the place and nothing should be taken as gospel at the moment, but I'm less convinced than I was a week or so ago that we will get a proper GH... and this would be a fairly major blow to the idea of a trop lead wave 2 assault on the vortex with resultant wintry synoptics for Europe through January. 

    • Like 5
    Link to post
    Share on other sites
    Guest
    This topic is now closed to further replies.
    • Settled, dry spell continues as daytime temperatures edge up a degree or so

      The risk of frost continues and it is chilly out of the sunshine but the fine, dry spell continues this week as the temperatures creep up, closer to average rather than below as they have been. Read the full update here

      Netweather forecasts
      Netweather forecasts
      Latest weather updates from Netweather

      2021 Arctic Sea Ice Melt Season Outlook

      Samual Hayes explores the trends and the main influencing factors as the Arctic Sea Ice Melt season for 2021 gets underway. Read the full article

      BornFromTheVoid
      BornFromTheVoid
      Latest weather updates from Netweather

      Cold waves hitting Europe continue to threaten growers, is there a link to climate change?

      Much of Europe, not just the UK, has experienced unseasonably cold weather since the Easter Weekend. A plunge of cold arctic air brought by northerly winds early last week brought several nights of frost and even snow across large swathes of Europe, followed by another wave of cold arctic air spreads across much of Europe this week. The frosts causing damage to new growth in vineyards and orchardsa0spurred on by a late March heatwave, the vineyards of France werea0particularly badly affected.

      Nick F
      Nick F
      Latest weather updates from Netweather 4
    • Recently Browsing   0 members

      No registered users viewing this page.

    ×
    ×
    • Create New...