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Please ensure that the majority of your posts in this thread are model related - a theme of model discussion needs to run throughout.
Some off topic chat and reactions are ok, but please use other, more relevant threads for entirely off-topic chat (such as snow reports, met office forecasts and general chat/moans about the weather or this winter).

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Worth noting on the 00z ECM ensembles that there are a fair few that go down the GFS para/ICON route, with a deeper low but the flow means the warmer air never totally makes it as far as it does on some of the other runs which keeps the precip wintry.

I have to admit I'm surprised by how snowy some runs are, they really don't look like they'd be that supportive. Interesting. Even for the south many have decent falls of snow.

Edited by kold weather
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For those who think the SSW was a bust take a look at this at T+3   Then look at the NW/SE jet axis over us, then look at the fact that the downwelling has been delayed but is just und

Feel I have an apology to make.  If people are wondering why this thread vanished for almost an hour, basically I went ahead a locked the thread first. Then, went and hid it. Was feeling fed

Leaked express headline for tomorrow.   #sorrynotsorry

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4 minutes ago, kold weather said:

Worth noting on the 00z ECM ensembles that there are a fair few that go down the GFS para/ICON route, with a deeper low but the flow means the warmer air never totally makes it as far as it does on some of the other runs which keeps the precip wintry.

I have to admit I'm surprised by how snowy some runs are, they really don't look like they'd be that supportive. Interesting.

Evaporative cooling coming into play perhaps? I think under heavy precipitation anything below zero uppers can be sufficient for snow, away from coasts of course. Lower the better obviously.

Edited by Weathizard
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4 minutes ago, kold weather said:

Worth noting on the 00z ECM ensembles that there are a fair few that go down the GFS para/ICON route, with a deeper low but the flow means the warmer air never totally makes it as far as it does on some of the other runs which keeps the precip wintry.

I have to admit I'm surprised by how snowy some runs are, they really don't look like they'd be that supportive. Interesting. Even for the south many have decent falls of snow.

Yup another thing is that low has moved south and east a lot more on the 144 hour chart compared to ysterdays 168 hour one!!the core has moved from west of scotland  on the 168 hour chart from yesteedays 00z to south west england on todays!!tell tale sign that ecm MAY be coming around!!

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20 minutes ago, Tim Bland said:

GFSp has patches of 25cm Dow depths for the far south and 20cm + for higher ground of Wales and Scotland by mid week.

GFSp is starting to be more consistent both short and long term so could be a good sign 

F0F046B3-2C5F-462F-A602-7D33304FD256.gif

Fantastic for snow starved south ????

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1 minute ago, Weathizard said:

Evaporative cooling coming into play perhaps? I think under heavy precipitation anything below zero uppers can be sufficient for snow, away from coasts of course. Lower the better obviously.

Possibly, it may also be being helped by a deeper system probably containing lower thicknesses as well but even so there are a lot of runs which don't look on the fact of it like snowy set-ups but there is enough cold air in front of the front that it still turns to snow.

So there maybe some slight agreement on a deeper low on the ECM ensembles, but no real agreement on the actual weather. ECM something of a outlier in terms of how much snow it gives to the south...IE nothing.

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4 minutes ago, kold weather said:

Possibly, it may also be being helped by a deeper system probably containing lower thicknesses as well but even so there are a lot of runs which don't look on the fact of it like snowy set-ups but there is enough cold air in front of the front that it still turns to snow.

So there maybe some slight agreement on a deeper low on the ECM ensembles, but no real agreement on the actual weather. ECM something of a outlier in terms of how much snow it gives to the south...IE nothing.

Ukmo is the perfect run this morning!!gives a snow event more widely i would with cold air staying in place!!

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Actually looking at the ensembles again, some of the snowier ones are pulling a small wave in front of the main low. This serves to take the wind from the slouth/SSE which draws in colder continental surface air which helps keep it as snow for longer.

However there is still a wide range of options on the table looking at the ECM. I feel rather sorry for anyone trying to make a forecast for Tues-Thurs next week!

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18 minutes ago, nick sussex said:

Still no resolution on the low .

The angle of attack though is better across the models but it’s how it phases with the troughing that’s still up in the air.

There have been a lot of changes since yesterdays 12 hrs runs so I wouldn’t put much faith in any solution until there’s agreement and that’s within day 4.

 

Tuesdays low is day 4 now so we should form on that soon Hopefully. Purely selfish / IMBY but I’m hoping UKMO has this one correct. I’ve also got one eye on your neck of the woods Nick as I’m off to Andora next week

BE8F5FCF-4E5D-46CE-9F87-2EC71B2B2B9F.gif

Edited by Tim Bland
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5 minutes ago, kold weather said:

Actually looking at the ensembles again, some of the snowier ones are pulling a small wave in front of the main low. This serves to take the wind from the slouth/SSE which draws in colder continental surface air which helps keep it as snow for longer.

However there is still a wide range of options on the table looking at the ECM. I feel rather sorry for anyone trying to make a forecast for Tues-Thurs next week!

Yup just checked the ecm snow charts and its snow midlands wales and north!!crazy considering how deep that low is!!icon i would say is an outlier at the moment with that shortwave low as it seperates it into 2 segments!!the others dont so maybe expect a slight downgrade on the 06z!!

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4 minutes ago, shaky said:

Yup just checked the ecm snow charts and its snow midlands wales and north!!crazy considering how deep that low is!!icon i would say is an outlier at the moment with that shortwave low as it seperates it into 2 segments!!the others dont so maybe expect a slight downgrade on the 06z!!

6z is gonna be an upgrade. We're gonna be in winter wonderland by 8PM tonight??

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7 minutes ago, Tim Bland said:

Tuesdays low is day 4 now so we should form on that soon Hopefully. Purely selfish / IMBY but I’m hoping UKMO has this one correct. I’ve also got one eye on your neck of the woods Nick as I’m off to Andora next week

BE8F5FCF-4E5D-46CE-9F87-2EC71B2B2B9F.gif

Hi Tim well conditions in the Pyrenees have improved greatly . At least a metre of new snow has fallen widely  .  More snow is expected over the next few days aswell so things are looking good .

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23 minutes ago, Weathizard said:

Evaporative cooling coming into play perhaps? I think under heavy precipitation anything below zero uppers can be sufficient for snow, away from coasts of course. Lower the better obviously.

Last year we had snow at night in northern England from 850’s around -2 because of evaporative cooling. D074B17B-6D60-4623-84DE-D89737EE333C.thumb.jpeg.7ecfd604f9c4978d586c055c68b64f9e.jpegThe south coast looking good if it can just nudge slightly north on the Ukmo model for Tuesday nightF0D22111-F335-41B5-B777-2E478BE5A48A.thumb.jpeg.c380d0f67f0d360ed6b41d1fec05d323.jpeg7BA95E64-8B73-45D6-8251-93466AA43B31.thumb.jpeg.b7f61abaec098bf3db0fc47ccc1c2b35.jpeg

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10 minutes ago, kold weather said:

So to explain how crazy marginal and difficult this set-up is, especially the further south you go here is an example.

Two of the ensemble members have what is basically the same set-up on Thursday morning. Both are around 960mbs, both center on W.Ireland and moving ESE. So without high resolution you could not tell the difference.

And yet one has 3-6 inches widely even in the south, and the other has 0 below B'ham. So why the difference?

The difference is BOTH have a wave feature on the front ahead of it turning the air southerly for the south. However the first one keeps it as an open wave meaning its not really drawing in any milder air from the south to any great degree...the 2nd just about forms a small tight closed low pressure/ This rotates around the parent low and drags up *slightly* milder air (maybe milder by 1-2c) BUT because it does that it makes the whole thing a rain event in the south, whilst the first solution gives a large amount of snow for all as it moves northwards.

At this time scale, its impossible to nail down such tiny features that could make the world of difference, and it really does make a world of difference on the ensembles!

It will definately be the 2nd one knowing our luck ??

This set up and who is in what camp etc reminds me of a 8 runner Handicap Chase at Haydock

2 have fallen, 2 are pulled up and 4 are left with 3 Fences to go, the even money shot and the 2/1 and 5/2 are clear from the 4th horse who is 66/1

At the last the Fav falls brings down the other 2 and the 66/1 shot is the only finisher

Sounds like the winter to a tee - Haha

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Very good overnight runs from ICON, GFS, GFSP and UKMO, although the ECM is not so good, so we have to be cautious.  Looking at the London GEFS there's pretty tight clustering on the 850's out to day 8 (although there's a bit of scatter around days 4-5)

image.thumb.png.550fb936e5c689583f4d241ba643eebb.png

I can't see to upload the table version of the 850's for London, but I would recommend checking them out.

 

 

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6 minutes ago, shaky said:

As expected icon joins ecm with that shortwave coming out of the states a lot quicker and also no 2 seperate lobes anymore!!

Yeah the 06z ICON won't be all that great unfortunately, but things are going to swing around still plenty yet!

Also would be fair to say the ICON has been shifting every single run recently.

Edited by kold weather
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14 hours ago, Ed Stone said:

The FV3 ends with remarkable Met O agreement...Once one's factored-out the 180 degree total wind vector-reversal, of course!?

image.thumb.png.340129bf1664c60b2779551b29e51a8c.png

Morning.im not seeing the excitement element this morning tbh? looking at the nhp  I can't see anything in the reliable to give a decent cold spell.yes some transient snow for some but nothing that will sustain.guess I've set the bar to high after many weeks of hype.anyone getting snow enjoy it for the short period it lasts.

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2 minutes ago, Jackski4 said:

Of course there is a chance that every single model is going to now follow ECM and we're all going to turn to alcohol by 11am..

Trust me mate theres a higher chance of that happening than an upgrade!!better to be dissapointed i say lol

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Adjusting my snowline down to derby across to stoke .....possibly a bit of a big jump down from Sheffield but you can see the trend currently is to correct south each run. 

Note the eps mean uppers at day 7 yesterday morning had the -4 c isotherm across the Scottish Borders - this mornings run across the midlands 

undoubdly correcting south but given the persistence of the ec op to phase the upper troughs and blow up the low, we are struggling 

Edited by bluearmy
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The ICON 00z was very similar to the GFS p ( & probably the UKMO ) for southern snow

here is the T90 chart 00z just waiting for the 06z

C0B4BBFE-5D4D-407B-A4EE-E6A5B8B9C3AE.thumb.png.6c5ab9c07b3755539e197e2e91bd6419.png

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3 minutes ago, Steve Murr said:

The ICON 00z was very similar to the GFS p ( & probably the UKMO ) for southern snow

here is the T90 chart 00z just waiting for the 06z

C0B4BBFE-5D4D-407B-A4EE-E6A5B8B9C3AE.thumb.png.6c5ab9c07b3755539e197e2e91bd6419.png

Its not as good as the 00z, basically a replica of the 00z ECM but a little more snow on Tuesday (but not huge amounts). Small amount of snow for the south, then the low deepens out west, and probably after 120hrs rain. Very poor BUT it is just one solution and there is a wealth of them out there. Probably would still be fine for the north though.

Ensembles really don't have too much agreement with how this roles still.

Edited by kold weather
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4 minutes ago, Steve Murr said:

The ICON 00z was very similar to the GFS p ( & probably the UKMO ) for southern snow

here is the T90 chart 00z just waiting for the 06z

C0B4BBFE-5D4D-407B-A4EE-E6A5B8B9C3AE.thumb.png.6c5ab9c07b3755539e197e2e91bd6419.png

Think it might have trended south steve but not by much especially considering how south you are lol!!

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