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Model output discussion - is the beast awakening?


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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester
    25 minutes ago, CreweCold said:

    -12 uppers and low thickness over the N Sea. Not a chance that would be dry.

     

    Bone dry for me South Manchester. 

    Unless it is a sustained Easterly with very tight isobars and low heights showers fizzle out 9/10.

    The only hope would be embedded shortwave low as too far away for lake effect showers.

    I am hoping the low acts more like GFSp then I wouldn't mind an icy dry Easterly if that is what transpired.

    Still, better get the Easterly first!

    Edited by Mucka
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    Quick summary, GFS cold and snowy by 144 Para cold and snowy by 144 Ukmo cold and snowy by 144 Gem cold and snowy by 156 ECM cold and VERY snowy by 156.  

    OMG I love this post . Shows just what a weird but wonderful bunch coldies are ! Your post in a nutshell sums up just how much this means for cold and snow lovers . Bless you Mike . 

    Yes ! Low pressure finally developing over northern Italy . A biting east ne flow heavy snow showers driven much further inland . Lots of instability . Enjoy the snow UK coldies . Really gre

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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    8 minutes ago, mulzy said:

    In contrast to the GEFS, the EPS mean rock solid.  Very cold days 5-8.  850 Means of -9/-10 widely by day 6/7.

    Then we need GEFS to flip very soon because GEFS are very very iffy at 00z...

     

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    Posted
  • Location: Barnsley
  • Location: Barnsley

    Can anyone in here explain to me why certain posters on here are saying this cold spell is OVER.  Ok the GFS has had 2 bed runs (mainly for the south east) but two things to note.  1 All other models are against it and how many times have we seen this model drop the cold fir 24 hours only for it to come back running with its tail between its legs

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    Posted
  • Location: Liphook
  • Location: Liphook

    The GFS is different from the rest of the models in two key ways:

    1: Stronger Iberian low from the rest of the models though it keeps a slight limpet low with a weak center near Scotland. Ironically closer to the older ECM/GEM.

    2: Stronger LP in the Atlantic with the core being solely in the southern part of the low complex. Much more progressive in how fast it is throwing the Atlantic LP SE.

    Combine the remains of the limpet low hanging near Scotland for longer, with a faster stronger Atlantic low, and you can see why the whole thing phases, and so even if the Iberian low behaves we still struggle.

    However the GFS does struggle with these lows and does quite often have a habit of strengthening these types of lows too far. 

    Still big differences this morning in several features even at 72hrs!!

     

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    Posted
  • Location: Bedworth, North Warwickshire 404ft above sea level
  • Location: Bedworth, North Warwickshire 404ft above sea level
    1 minute ago, Jon Snow said:

    Just looked 👀 at the 0z and to me, there’s still plenty of stunning output showing bitter easterly winds and snow showers, severe frosts / wind-chill etc...that may sound OTT but with uppers (T850’s) plummeting to minus 12 or lower in places..it’s no exaggeration!...🥶😜

    yes, but we cannot ignore the elephant in the room the GFS, I think most people feel quite alarmed by the way it's flipped so drastically in the medium term.

    I'll go with the GFS, as I know I won't be disappointed

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    Posted
  • Location: Leicester
  • Location: Leicester

    Looking at the ecm the cold spell starts on friday night!!!!dont over look the 850s on friday!!some peeps could get snow from that stubborn low filling over us!

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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire
    8 minutes ago, Blessed Weather said:

    Here's the latest model verification stats for the Northern Hemisphere. This is the 500hPa anomaly verification and top dog is ECM followed by UKMO. Performance closer to 100% is best. The problem for us in the UK is the stats are measuring the performance across the entire NH and do not necessarily reflect performance relative to our little island sat on the edge of the Atlantic and the continental landmass.

    628038924_Verifto27Jan21.thumb.jpg.fe841f250721453359dbe3bdd5c80bdc.jpg

    Source: https://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

    Here's how the Met Office describe verification

    The VIPP team carries out continual monitoring of the models performance, in conjunction with detailed comparisons against a wide range of satellite and remote observations and feedback from forecasters, enables us to develop physically based and testable hypothesis of the causes of model problems and systematic biases, and develop model changes which address them........ Forecasts are compared against a variety of observations, from standard observing sites to remotely-sensed observations  (e.g. radar, satellite).

    Source: https://www.metoffice.gov.uk/research/weather/verification-impacts-and-post-processing

    Finally, an interesting presentation given by ECMWFNWP Verification: what can be learnt? 🙂

    Gordon's alive! Thanks Blessed!

    Reasons to be cheerful, glass half full etc. 

     

    In other news @MattHugo discusses his issues with gfs flip vs ao on twitter, here's the link to twitter thread for anyone interested.

     

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    Posted
  • Location: Liphook
  • Location: Liphook
    Just now, cyclonic happiness said:

    yes, but we cannot ignore the elephant in the room the GFS, I think most people feel quite alarmed by the way it's flipped so drastically in the medium term.

    I'll go with the GFS, as I know I won't be disappointed

    Reasonable enough.

    I think there is some logic in thinking the GFS is well...GFS'ing.

    However on the other side of things the macro details are very similar on the models, its just the GFS strengthens both things that we need to remain weaker. Its basically the worst case (which is still good for the north, hence why I think the north is utterly locked in now.)

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

    Well 6z GFS is another nail biter.

    If you are a coldie like myself another GEFS set like 00z and the concern will only increase.

    Could the 6z GEFS flip back?

    I really hope so.

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    Posted
  • Location: Somerset
  • Location: Somerset

    So yesterday ECM was clearly broke and GFS was the most reliable, today it’s switched!  Seems like people are taking what they want from whichever is the best model, rather than looking at the trends?

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    Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
    2 minutes ago, JimBob said:

    So yesterday ECM was clearly broke and GFS was the most reliable, today it’s switched!  Seems like people are taking what they want from whichever is the best model, rather than looking at the trends?

    Evidently Jim Bob you haven’t look at models the consensus is cold easterly.

    Edited by Daniel*
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    Posted
  • Location: Bury St Edmunds, Suffolk
  • Weather Preferences: Cold, frost and snow
  • Location: Bury St Edmunds, Suffolk

    So we have the ECM going very cold, plus we have the UKMO on board with their text forecasts.

    Everything points to this easterly, just that pesky GFS now. Is it right or is it wrong? Going by the other models and METO you'd have to think it's wrong, but we all know it's just not that simple.

    The GFS was the first to pick up this potential easterly and ran with it pretty consistently for a few days. Now we see the wobbles, the GFS often does this when it's the first to pick up a pattern only to revert back to it's previous output over the following 48 hours or so. So let's hope to see it edge back to look more ECM over the next day or so. But don't expect a sudden flip, look for small crawls back to what it was showing 24 hours ago.

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    Posted
  • Location: Cambridge
  • Weather Preferences: Heavy snow & long hot summers
  • Location: Cambridge

    Another battle of the models I see!

    ECM will likely follow the GFS, then both back track a little. So in conclusion no Easterly looks like a very possible outcome, more than 50:50.

    Edited by DCee
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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    Just now, DCee said:

    Another battle of the models I see!

    ECM will likely follow the GFS, then both back track a little. So in conclusion no Easterly looks like a valid outcome.

    But UKMO ,GEM ,ICON all follow EC ..

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    Posted
  • Location: Liphook
  • Location: Liphook
    4 minutes ago, Roger J Smith said:

    When the GFS and ECM diverge, I like to check which one the GEM supports, and in this case it is definitely the ECM

    The GFS has also changed its output drastically over two or three runs across N America. 

    Would say the odds are maybe 2:1 in favour of the cold solution in Europe, still trying to assess what's implied by all these flips in N America.

    No pro forecaster is going to go much further than "possibly turning colder next week" at this stage. 

    The difficult thing in this set-up is relatively small differences that normally wouldn't make a huge difference in any other time of year, makes a large difference at this time of year.

    A 5-10mbs difference and perhaps 100 miles difference in both lows is the big difference between the models and yet that is the difference between snow and cold for the south, or cool and rainy.

    ICON is actually not drastically far from the GFS, but the Lps being weaker allow us to get away with it, just about.

     

    Edited by kold weather
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    Posted
  • Location: Pontypool, 132m ASL
  • Weather Preferences: Extremes
  • Location: Pontypool, 132m ASL
    21 minutes ago, IDO said:

    The whole GFS suite has gone less cold for the south compared to the 12z from yesterday:

    yesterday>595916981_graphe3_10000_305.3763427734375_153.287109375___(1).thumb.png.2675f2ec5c2fe1f70cab4191c9618c32.png 0z>graphe3_10000_305.3763427734375_153.287109375___.thumb.png.4c7ea74f17d23f7ef86af6f3bb384438.png

    The control and the op were in the coldest cluster (12z) and probably at the margin of our coldest possible solution so maybe understandable. Unfortunately the op and control are now following the milder option (synoptic) and the op is clearly the worst case scenario in that envelope. 

    None of us know which is the right or wrong solution and it is a question of just waiting for the music to stop? Clearly the ecm will give the south 5-7 days of cold and snow and the gfs gives us just a day! I would at this range usually go with the ecm but...

    I still think every option is up for grabs after 5th as I posted yesterday - spaghetti and no consistency after 5th:

    GEFS from yesterday 06z, 12z and today 00z

     

    gfs-pontypool-gb-515n-3w (4).png

    gfs-pontypool-gb-515n-3w (5).png

    gfs-pontypool-gb-515n-3w (6).png

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