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Model Output Discussion - Snow for some, but what else is in store?


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Ok, I have a bit of an update. Looks like the correction westward for today got the predicted snowfall about right . Nowcasting really comes into its own for this weekend. The team think another corre

Please allow me this small divergence mods... I feel like the last 3 weeks have been a bit of a blur. I caught Covid tail end of 2020 and was really rough with it. Low oxygen levels leading to in

I have had it once in October and again December the 30th. Theres a bit of chat over whether i have had it once had long covid and tested positive again as symptoms came back in December or caugh

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Posted
  • Location: st albans
  • Location: st albans
    47 minutes ago, IDO said:

    You are my harshest critic, but I make no bones about it and never have, I focus on the medium term. There are plenty of comments on pre-d5 but that takes little in the way of interpretation from my POV as the verification is very good at that point. 

    For me, looking at that d13 chart, here:

    1835968893_gensnh-31-1-324(1).thumb.png.0d9b3262c26b9f219ab66068d4f02fc3.png

    I am intrigued by the continuation of that reverse zonal flow to our north, in a mean at that range. That may in fact be an imprint from the strat? If not what is going on? These questions and possible answers pique my interest!

    Posters still get excited by the much discredited d10 ecm height-biased charts but you do not disparage those. The ecm d10 mean:

    1182219543_EDE1-240(1).thumb.gif.e2c8352a23226e7b27d3e65fa7484261.gif

    We can all enjoy different aspects of model watching and if you disagree maybe some reasons other than it is d13, and your alternative take so we can have a pleasant discussion? Cheers.

    It’s quite normal for the gefs and eps mean/anoms to be v similar 

    Why the gefs are being dissed I’m not quite sure ?  I didn’t gefs were being replaced soon - they’ve not long been upgraded ??

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    Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

    GFSp 12z Trickling out and looks broken. Not sure if that has anything to do with the delay but basically the low acts quite strangely stalling over the UK instead of moving slowly E/NE. Even at 96h it is few hundred miles further W than other output

    Here it is at 120 V UMO and ECM

    gfsnh-0-120.png?12UN120-21.GIFECH1-120.GIF

    Probably best to take with a pinch of salt

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    Posted
  • Location: Solihull, WestMidlands, 121m asl -20 would be nice :-)
  • Weather Preferences: Cold and Snow -20 would be nice :)
  • Location: Solihull, WestMidlands, 121m asl -20 would be nice :-)
    13 minutes ago, Had Worse said:

    image.thumb.png.bbc16b6cac2ebdfce6c6103657f045d6.png That straggling front over the Northwest is further south.

    That would be in line with GEFS pert 20, by Thursday large parts of England would be buried 🤗

    image.thumb.png.b5d962f6f06ca788a39cf69559a10c33.pngimage.thumb.png.4405d87f3986955c466ddd31cb12cbfb.pngimage.thumb.png.5f0187d579ebb70b0635a0f099e138b2.png

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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    9 minutes ago, virtualsphere said:

    Worth taking a look at the charts for the rest of Jan and Feb 2013 before that famously cold March.  The high latitude blocking ebbs and flows, and we get synoptics like this - for the UK, not dissimilar to what is being suggested for us towards the end of the week, even if the rest of the NH pattern is a little different.  Still a lot of interest left this winter I think, given how the rest of that winter / spring turned out!  

    That's a very interesting comparison to 2013.  At the end of January 2013, it turned milder for a time and then alternating cold/mild unsettled periods through February but never very cold or very mild.  I believe there were only transient snowfalls for most?  This continued for much of the month and overall was colder than average at 3.2C.  I see what you mean for the end of this week looking similar.

    Edited by Don
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    Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)
    7 minutes ago, Dancerwithwings said:

    That would be in line with GEFS pert 20, by Thursday large parts of England would be buried 🤗

    image.thumb.png.b5d962f6f06ca788a39cf69559a10c33.pngimage.thumb.png.4405d87f3986955c466ddd31cb12cbfb.pngimage.thumb.png.5f0187d579ebb70b0635a0f099e138b2.png

    The 528 dam line is through central Scotland on the meto chart? Perhaps high ground of northern England seeing something wintry , but I wouldn’t say large parts of England getting buried ?

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    Posted
  • Location: Solihull, WestMidlands, 121m asl -20 would be nice :-)
  • Weather Preferences: Cold and Snow -20 would be nice :)
  • Location: Solihull, WestMidlands, 121m asl -20 would be nice :-)
    4 minutes ago, Tim Bland said:

    The 528 dam line is through central Scotland on the meto chart? Perhaps high ground of northern England seeing something wintry , but I wouldn’t say large parts of England getting buried ?

    Sorry TB, I should of said looking at these pert 20 precipitation charts 🥴

    CA4BD160-8CCB-46D6-B864-942B8A594CDA.thumb.png.b09563ff576a0b368f80c11de6a6fe77.png

    Edited by Dancerwithwings
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    Posted
  • Location: Ludgershall, Wiltshire
  • Location: Ludgershall, Wiltshire
    9 minutes ago, Tim Bland said:

    The 528 dam line is through central Scotland on the meto chart? Perhaps high ground of northern England seeing something wintry , but I wouldn’t say large parts of England getting buried ?

    That's a shame as last nights METO fax chart for Thursday had the 528 dam covering all but the far south west!

    Edited by Don
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    Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

    ECM ensembles ... hmmm, not quite the update I was hoping for - op run at D10 only supported by about 10-20% - also in D12-D15, the signal for getting the jet south not quite as far south as on the last few sets. Could just be the waxing and wanings of different ensemble runs, they're never exactly the same! 

    I'd still be pretty happy if I way seeking a lot of snow and I lived Lancs Yorks or further north. And the cold flow from the east towards Shetland is still preferred into FI, and while that's there there's always a good chance just one Atlantic ridge could bring the house down. 

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    Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill
    35 minutes ago, Mike Poole said:

    Well the ECM clusters are a thing, 5 in the pre T96 timeframe, then 1 only in the next two timeframes, then 3 in the long range T264+:

    10BD29B2-A408-4D19-9E53-E6C3C35F08EF.thumb.png.1db9543544da9b71c2810de121d19762.png

    So in the mid range there is too much uncertainty to split clusters, and then there is in the longer term.  This happens sometimes, particularly when a SSW is the hidden driver of patterns down here.  

    So what of the 3 clusters?  Well some HLB is clear for all, but it is way too far north most of the time, Cluster 3 looks like a route to a Scandi high which would probably suit us best.  But don’t forget the uncertainty earlier.  

    I do not know the inner details of the ecm clustering but I would say it possibly uses top-down algorithms. So the AI would use different focal points for the early charts due to their lower spread over time, maybe a position of a low within a cut-off low, but as we reach say d8 the focal point(s) will probably be more long wave differences.

    The way I would see it is that the 5 clusters pre-d4 are more to do with micro-variations. If these micro-variations were drivers for pattern changes then the clusters would remain high at d8 (eg), but if the clusters reduce to 2, IMHO it would mean that the underlying pattern is not greatly affected by earlier clustering (differences), suggesting that there is confidence in the ensembles for d8. At the point in time we get 3 clusters then we could suggest the ensembles are diverging a bit more.

    Of course, garbage-in garbage-out, so we are making a big assumption that ecm ens are good, but that is really the point of ensembles so you can make that assumption. Add in that the gem and gfs ensembles are giving the same feedback, from the current runs/suites it is fair to put some faith in what they are showing, but as others say, weather will do what it wants and we can only best guess.

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    Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
    10 minutes ago, Don said:

    That's a shame as last nights METO fax chart for Thursday had the 528 dam covering all but the far south west!

    What was posted regards Wednesday and the waving front very large rainfall totals expected going by FAX looks worst through Wales and north Midlands further south than originally expected. That’s remained unchanged. Don’t understand why FAX chart is posting as a link?  @Paul

    AE6972AF-A097-4258-BBD8-21B3A346DF18.webp

    Edited by Daniel*
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    Posted
  • Location: Coventry
  • Location: Coventry

    Icon at 120 v 12z run

    Low looking more likely to disrupt and send energy towards our south.

    Slightly colder 850mb temps over the UK too.

     

    iconnh-0-120 (23).png

    iconnh-0-126 (12).png

    Edited by Battleground Snow
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    Posted
  • Location: Penrith Cumbria
  • Weather Preferences: Cold, snowy winters and warm sunny summers
  • Location: Penrith Cumbria

    Great ECM, the mild westerlies die on there feet next weekend and the cold wins out. Darren Betts clearly reading from the ECM script ramping the snow up for Thursday and stating that we stay cold for the foreseeable.

    The mild spell is dead in the water.

    Andy

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    Posted
  • Location: Hampton, Evesham, Worcestershire. 27m asl.
  • Weather Preferences: Extreme and Exciting weather, hate stratus clouds and drizzile
  • Location: Hampton, Evesham, Worcestershire. 27m asl.

    Snow Surprises by the end of the Week.....!!!!

    h850t850eu-18.png

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    Posted
  • Location: st albans
  • Location: st albans

    Para day 10 NH view has a very broken tpv look about it 

    I wonder what might have caused this ? 
     

    image.thumb.png.102795392a14c6080a764c0f1f836575.png

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    Posted
  • Location: North East Hampshire
  • Location: North East Hampshire
    1 minute ago, ANYWEATHER said:

    Snow Surprises by the end of the Week.....!!!!

    h850t850eu-18.png

    What model is that? 

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    Posted
  • Location: st albans
  • Location: st albans
    5 minutes ago, Battleground Snow said:

    Icon at 120 v 12z run

    Low looking more likely to disrupt and send energy towards our south.

     

     

    iconnh-0-120 (23).png

    iconnh-0-126 (12).png

    I don’t see that day 5 as being an improvement on the 12z run ....

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    2 minutes ago, bluearmy said:

    Para day 10 NH view has a very broken tpv look about it 

    I wonder what might have caused this ? 
     

    image.thumb.png.102795392a14c6080a764c0f1f836575.png

    Why is that low shown in the Norwegian Sea almost every run? Is it because of the temperature differential of cold Siberian air hitting the warm N. Atlantic ocean, or, is it a consequence of the pressure pattern with relatively high pressure circa Iceland / Greenland and the low pressure coming off the ESB and extending into the Atlantic?

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    Posted
  • Location: BS15 8bx
  • Location: BS15 8bx
    5 minutes ago, Penrith Snow said:

    Great ECM, the mild westerlies die on there feet next weekend and the cold wins out. Darren Betts clearly reading from the ECM script ramping the snow up for Thursday and stating that we stay cold for the foreseeable.

    The mild spell is dead in the water.

    Andy

    If that is the forecast from a pro why is nobody posting BOOM charts? Seems very downbeat in here considering Darren’s take on things. Confused.com. 

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    Posted
  • Location: Coventry
  • Location: Coventry
    6 minutes ago, bluearmy said:

    I don’t see that day 5 as being an improvement on the 12z run ....

    Probably isn't really, a bit colder over the UK, the interest is much past 120.

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    12 minutes ago, bluearmy said:

    Para day 10 NH view has a very broken tpv look about it 

    I wonder what might have caused this ? 
     

    image.thumb.png.102795392a14c6080a764c0f1f836575.png

    Ha - Do i detect a hint of sarcasm there??

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    Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire
    4 minutes ago, Richard Fisher said:

    If that is the forecast from a pro why is nobody posting BOOM charts? Seems very downbeat in here considering Darren’s take on things. Confused.com. 

    It might be because often people are looking for -15c 850s and the mother of all cold spells.

    The current output is suggesting a snowfall risk Friday into the weekend on a slightly more marginal flow. A northerly flow initially with fronts wrapping round with some colder air digging in. Then we have showers blowing inland, wintry with snow in some place. Then there is the potential for Atlantic fronts to push into the colder airmass with heavy snowfall on the leading edge.

    A messy picture, but with a decent risk of snowfall for some areas.

    No booms, but lots of interest!

    Lets do the booms on Monday in the regionals 😉 

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