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Model Output Discussion - 14th Jan 12z Onwards


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Posted
  • Location: Santry, Dublin, Ireland. 50 metres ASL.
  • Location: Santry, Dublin, Ireland. 50 metres ASL.

    Indeed it is, but that is showing a very slack flow, no precipitation really, but damned cold. And also, it's also going only one way after that… Sadly!

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    I'm fairly certain when Frosty see's this chart:     He's going to be outside doing a lot of this:  

    My last post this morn as I'm fed up with the misery in here already. The UKMO at 144 has the PF straddling the UK & a stalled frontal line delivering snow on it similar to feb 96 - It is more a

    Or perhaps it means instead that some 'apparent' absentees are sitting back and looking at a very much bigger picture than simply building cyber snowmen to get knocked down, re-built, and then knocked

    Posted Images

    Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

    looks to me like that trough exiting the eastern seaboard of america is expected to push the atlantic ridge across us rather sooner then originally expected. post-2797-0-09839800-1421404721_thumb.gi

     

    trapping the east under cold uppers, but without any 'feature' to provide precipitation , its looking cold and frosty by next thursday

     

    post-2797-0-27549100-1421404858_thumb.gi

     

    before collapsing all the way allowing the atlantic back in

    post-2797-0-22155000-1421404901_thumb.gi

     

    this i believe is supported by

     

    post-2797-0-80109200-1421404957_thumb.gi

     

    so the gfs 06z might be an unpopular run, but its a feasable evolution with some support.

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

    At least after the GFS 06hrs run we have broad agreement on the overall pattern.

     

    So low pressure will stick to southern Greenland extending shortwave energy s/se through the UK, this may separate briefly to give a slack easterly flow.

     

    As for detail hard to pin down, if you're currently in a snow favoured area my advice don't get the sledge out and if you're in a currently unfavoured area don't throw away the sledge brochure!

    Edited by nick sussex
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    Posted
  • Location: Chipping Norton, 220mts /720ft asl
  • Location: Chipping Norton, 220mts /720ft asl

    Feb 1996

     

    Rrea00119960206.gif

     

    Now:

     

    gfsnh-0-114.png?6

     

    Many NW members are still receiving counselling after the 'Beasterly that disappeared' in Feb 06

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    Posted
  • Location: .
  • Location: .

     

    so the gfs 06z might be an unpopular run, but its a feasable evolution with some support.

     

     

    Yes. Taking T168 as limits of reliability, the jet is fired back up, less split and with less amplification. It's basically barrelling out of the eastern seaboard:

    generating cyclogenesis with it:
     

     

    Ouch:

     

    And we end up back with Atlantic muck:

     

     

    This was the trend the 0z picked and now the 6z has given it another huge shove. It will be interesting to see if this has much support or is an outlier. I hope the latter.

     

    Meantime, we should make the most of the next 5 or 6 days. A change isn't set in stone, and anyway it would be all the more reason to enjoy the cold spell that we do have within the reliable timeframe.

     

    Edited by West is Best
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    Posted
  • Location: West/East/Sussex Surrey border
  • Location: West/East/Sussex Surrey border

    Each run that goes by, the high to the east is encroaching more and more, I see an easterly in about 10 days time, after a small bite of the cherry now.

    Yet others above this post saying the jet stream is saying no to the above

    Confused

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

    I am looking for Dr Cohen's negative AO in GFS FI but it is worrying that the PV is going in the opposite direction:

     

    post-14819-0-80647100-1421406127_thumb.p

     

    It is puzzling though the 0z mean supports it: post-14819-0-56150500-1421406208_thumb.p

     

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    Posted
  • Location: Raynes Park, London SW20
  • Location: Raynes Park, London SW20

    Folks need to calm down.  The models have not indicated a scenario of  -15 uppers with a potent easterly bringing snow/snow showers to many - but they are showing a very messy complex synoptic pattern with the POTENTIAL of snowfall (albeit marginal for some)  anywhere in the next 5-7 days.

     

    ensemble-tt6-london.gif

     

    This clearly shows the ECM Det is on the milder side of the whole ECM ENS suite.  Still lots to play for in my opinion...

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    Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

    It seems that the AZH is again going to be a pain in the butt, it is now heading away from a memorable spell to just a cold spell as it stands.  

    My review thus far as regards to where I think we are heading is that its a nice bonus as this is looking a lot colder than anticipated at this junction.  For me heights to NE are favoured and should stay in place but as I mentioned the other day it's positioning is crucial.  Couple of days ago it was perfect, now its less favourable, will it be modelled differently on the 12s or tomorrow?  who knows. [active stormwatch 20/21 anticipating strong Atlantic activity trying to push in against cold air and could be very/nicely messy] Going beyond I'm anticipating these heights being removed as we head towards months end [slow or quick? don't know but a prolonged easterly wasn't in my book and am not going to be hunting that scenario]  with very cold trough taking over turn of month and UK under northerly quadrant regime as the PV shifts to 'our' side of the hemisphere.

    So my cup is over half full and filling at the moment

     

    BFTP

    Edited by BLAST FROM THE PAST
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    Posted
  • Location: Alvechurch 8 miles South West of Birmingham
  • Weather Preferences: Snow
  • Location: Alvechurch 8 miles South West of Birmingham

    This cold Snap\Period hasnt really started to get going yet and already some people are looking for the end???

    i use to be a regular on here but with so much sniping going on i prefer to keep my head under the parapet!!!! 

    Oh By the way it will be a snowy week for quite a few next week!!! :wallbash:  :wallbash:  :wallbash:

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    Posted
  • Location: Reigate, Surrey 78m asl
  • Location: Reigate, Surrey 78m asl

    Well, and I know it's lala land, but I wasn't expecting such an angry pv over Greenland in 10 days time...

    http://www.wetterzentrale.de/pics/Rtavn2401.gif

    That strikes me as a mighty quick reformation after a good mjo, half ssw etc...

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    Posted
  • Location: Frome 330ft ASL
  • Weather Preferences: Most(see in interests section.)
  • Location: Frome 330ft ASL

    Blast, Have to agree with you but i`m so happy to be looking for to a cold sometimes snowy week. Week is better than nothing and yes azores high been bugbare all winter , to far north and wrong shape.

     

    Saying that though i`m old enough to remember when cold was forescast to break down but just kept going.

    I remember long fetch siberian winds lasting for about a month at times ( back in the Francis Wilson forecasting days on Bbc breaksfast news).

     

    So cold pretty much guranteed with ice days for one week then there after even though mild showing its still anyones guess until 3-4days out until next Friday/Saturday.

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    Posted
  • Location: Leeds
  • Location: Leeds

    Meto warning for snow potential on Sunday in the SE quadrant of the UK doesn't tally with their own fax chart, the latter showing the front further north:

     

    attachicon.gif20150118 Warning.png

     

    attachicon.gif2015011812zT+60.png

    my analysis of this would be the highlighted area is where rain is fairly guaranteed however further North of this warning area may warrant a warning for snow, however as there is great uncertainty concerning this a warning may not be issued until Saturday as was the case with Tuesday's snowfall here in the Midlands. The fax chart shows the front is definitely further north than the warning area so expect and update tomorrow. Euro4 and NMM will be helpful for this forecast more so than GFS
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    Posted
  • Location: Pershore
  • Location: Pershore

    Just removed a set of posts discussing the met office warning's - please head over to the general discussion or regional threads for these as it's not model discussion. 

     

    https://forum.netweather.tv/topic/82292-upcoming-cold-spell-discussion/

    https://forum.netweather.tv/forum/142-regional-discussions/

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    Posted
  • Location: Addington
  • Weather Preferences: Love a bit of snow
  • Location: Addington

    At least all models have the potential to upgrade later today.

    Far better than looking at epic runs that only have downgrades to come later.

    Very complicated setup which could end up as a classic.has the potential at least which is exciting.

    Keep the faith.

    Far , far better than this time last year.

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    Posted
  • Location: Chichester West Sussex
  • Weather Preferences: Cold and snow
  • Location: Chichester West Sussex

    It's apparent that the models underplayed the power of the jet and as we get closer in time to this cold snap the models will firm up on finer details, one of which is the jet stream which powers our weather. We have I say at best a 5-7 day cold/cool spell with night frosts but any precipitation will be rain away from high ground and the north. We could still get an upgrade but the high pressure just gets flattened to quickly. Until we have some decent blocking to our north then low pressure will just crush any chance of deep cold.

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

    Looking at the GEFS at D6 the op and Control (more progressive with the Atlantic) lead a majority cluster (>50%). The rest are all over the place. Some nice outcomes by D8 (9 members) showing some cold synoptics: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=192

     

    TBH I would ignore this run and let them reboot the system for the 12z as to me Shannon Entropy has taken over the show, with big differences even at D4. Still time to flip back to a longer cold spell as the 06z shows, but we need signs in the next two runs.

     

    With regard to snow, that has changed nearly every run and it may not be till Sunday morning till we know what will happen in the south re the heavy precipitation.

    Edited by i'm dreaming of...
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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Looking at the GEFS at D6 the op and Control (more progressive with the Atlantic) lead a majority cluster (>50%). The rest are all over the place. Some nice outcomes by D8 (9 members) showing some cold synoptics: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=192

     

    TBH I would ignore this run and let them reboot the system for the 12z as to me Shannon Entropy has taken over the show, with big differences even at D4. Still time to flip back to a longer cold spell as the 06z shows, but we need signs in the next two runs.

     

    With regard to snow, that has changed nearly every run and it may not be till Sunday morning till we know what will happen in the south re the heavy precipitation.

    Yes I think Shannon has returned big time! I'm not sure we'll see a quick return of any easterly but I still think the GFS is too flat and for that matter the ECM later on.

     

    The GFS  output holds the northern Italian low in place but is still determined to send the energy over the top.One would expect a bit more energy to head se, nice to see the new GFS is just as biased as the old one!

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    Posted
  • Location: Burton-on-Trent
  • Location: Burton-on-Trent

    We need an upgrade on the 12z otherwise we can forget about a widespread snow event on Tuesday. And for your own health don't look at the GFS perturbations. I got as far as number 2, where they were all showing zonal weather in 4 days time, before I couldn't view any more. UKMO is the only one showing anything decent in terms of snow potential on Tuesday. We need that Azores high to collapse like it did on UKMO.

    Edited by Snowy L
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    Posted
  • Location: East Lothian
  • Weather Preferences: Not too hot, excitement of snow, a hoolie
  • Location: East Lothian

    I'm well aware that I'm adding to this but I don't think people will ever be able to understand the difference between 'Model Output Discussion' and 'Ramps and Moans Discussion'. Both threads are completely different, yet every day we see people discussing MetOffice warnings or asking if it will snow. The moderators make it clear about a dozen times each day telling people the difference, this could be avoided if people used their common sense. I don't often moan, and I'm sure this post will be deleted, but I want informed opinion on model output, not discussions about warnings or whether it will snow in Peterborough. There is a separate thread for that.

    You are right and for long time users of these threads, it is clear to see where topics should be. But for newer/infrequent users the boundaries are difficult. Sometimes a one line question goes off at a tangent and if 5 people answer on top of each other, it can look like a massive swerve off topic. I realise there will be a few users who should know better, but gentle help showing the right direction would probably be gratefully received by those who accidently step off the path in the early days. This latest wintry spell is drawing in new people

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    Posted
  • Location: Cork, Ireland.
  • Weather Preferences: Storms frost snow heatwaves
  • Location: Cork, Ireland.

    Morning all

     

    Although I expect this thread is likely be a bit tense given the overnight outputs. Firstly the easterly or as the case maybe the Easterly curse has struck, essentially today I think the games over for that, once energy from the ejecting low out of the ne USA phases with troughing to the west of the UK then you cant clear shortwave energy to allow the Azores to ridge over the top.

     

    Part of the problem is the low upstream flattens out and then phases with another piece of shortwave energy heading out of the USA plains.

     

    And even if the easterly verified we would need to see colder 850's than was projected, of course we'll never know now! It never looked like a 5 star easterly, about 3 stars especially given recent trends.

     

    So we can either just let this disappointment consume the thread all day or just make the best of whats on offer which is still interesting.

     

    Theres still a very small chance that the GFS might be right as NCEP have commented on a lot of uncertainty over the eastern USA however the diagnostic discussion upto T84hrs goes with a blend of the ECM/UKMET and ECM mean for that area, given the timeframes involved and the agreement between the ECM and UKMO operational runs I would be shocked if they're wrong.

     

    So having left the easterly behind the new trend is to have the UK on the dividing line with troughing disrupting and frontal snow possibilities, this type of set up is a total nightmare to forecast, much now depends on what the models do with the boundary between rain/snow.

     

    This type of set up still opens up the chance in the future for another go at an easterly but the placement of the dividing line is crucial because a hundred miles either way will make a big difference and if the models edge the pattern too far east then that wouldn't be good however that seems unlikely at this point.

     

    A good feature to view is low pressure over northern Italy, if that remains then good snow chances will continue for the UK as this a " marker" for cold for the UK.

     

    So overall I understand that some people will wake up and want to kick the cat or punch their laptop but the door hasn't closed on snow and cold, its just taking a different route. 

    On viewing some of the latest charts, Frosty and many others who were anticipating the cold conditions to become more entrenched have no doubt gone one better

     

    :wallbash:

    http://www.gifbin.com/bin/112010/1289908258_strange-scare-reaction.webm

    post-17830-0-94614000-1421410018_thumb.j

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    Posted
  • Location: Morecambe
  • Location: Morecambe

    Must admit, I never expected to easterly to vanish just like that although as I mentioned yesterday, I had my doubts whether it was cold enough or not(was probably cold enough for sleet/snow but lying snow?) however its still disappointing just how much the models have trended away from the easterly.

     

    So its relying on frontal snow for the most part it seems and I really would not get all worked up regarding detail of this just yet, it will vary no doubt for sure. 

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