Model Output Discussion - Christmas and New Year

[stratty]

Just now, bobbydog said:

Whilst everyone is worrying about the next few days giving us a few snowflakes, (though I for one would love to see it..) we should be looking (wishing) for a cold pool to spill into Europe. 

 

Has anyone seen what's going on 'upstairs'?.....

 

Now that... is a rare thing of beauty... 

Next few days lol I'm looking at the next few hours!    

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[Tim Bland]

Big improvement on the GEFS. Op definitely on the mild side and has very little support...

[Tim Bland]

5 minutes ago, Kasim Awan said:

The eastwards track is looking less likely now.

I’m more worried about whether there is anything worth tracking

[bluearmy]

1 minute ago, Tim Bland said:

Big improvement on the GEFS. Op definitely on the mild side and has very little support...

I reckon 25/30% support Tim on uppers alone ?   That’s a reasonable cluster if the sypnotics are in broad agreement  ??

 

[Howie]

6 minutes ago, The BEAST From The East said:

Genuine question, I understand a little about SSW and the affects it could have to increase our cold chances but I think it was last January or the year before the BBC and on here were saying how it looked like The end of jan and through Feb it looked like being record cold and snowy yet here in kent we ended up with a record warm February and I seem to remember the temperture hitting a crazy 20+ on a few days..  What could have made it all go so wrong and could it happen this time around.. Thanks.. ?

That's because it didn't downwell into the troposphere 

[Kasim Awan]

3 minutes ago, Tim Bland said:

Big improvement on the GEFS. Op definitely on the mild side and has very little support...

Gfs op was not handling the tropospheric jet split well at all & sending too much energy north. Euro ENS' have a vastly improved grasp on this & are favoured. Icon 06z is marginally more amplified around Iceland at 120h.

[Kasim Awan]

2 minutes ago, Tim Bland said:

I’m more worried about whether there is anything worth tracking

There 100% is 

[Tim Bland]

2 minutes ago, bluearmy said:

I reckon 25/30% support Tim on uppers alone ?   That’s a reasonable cluster if the sypnotics are in broad agreement  ??

 

Yes, probably c20% of runs in the same camp as the Op. probably easier to see in list form. Op was 4th mildest at the point there is an uptick. My positive self is saying that worst case scenario it’s an opportunity to reload with some serious cold over scandi / east Europe & our north to tap into once the effect of the SSW kicks in... 

[tight isobar]

Large swathe England/wales now.in yellow-warning area!!.. now we can start on precipitation charts..!

Edited December 27, 2020 by tight isobar

[snowking]

In the shorter term still great uncertainty around any snowfall potential tonight and tomorrow, but also worth keeping an eye on Tuesday, with another LP running down the western side of the country, some models (eg Icon and Arperge) swing this system into central areas - these are the sorts of features which you just can’t anticipate showing up until short notice, but make scenarios like this a fascinating watch

[The Beast From The East]

7 minutes ago, Howie said:

That's because it didn't downwell into the troposphere 

Thanks for reply, so does it look like this time round it has or will?

[sheikhy]

Now now according to that warning from the meto we could see the snow as far as the east midlands

[tight isobar]

The Arpege forme-@24 hrs =top performer..everyone to their own-n-all that !!!

Edited December 27, 2020 by tight isobar

[Skullzrulerz]

14 minutes ago, Tim Bland said:

Big improvement on the GEFS. Op definitely on the mild side and has very little support...

A bit misleading to say that it has very little support 

The majority do seem to remain below average but there is a "pack" that certainly does 

One to keep a eye on 

[Frosty.]

The world is changed,  I feel it in the water, I smell it in the air, etc etc..anyway, the ECM 0z ensemble mean is cold god dammit!

[Scott Ingham]

There is yet another area of snow shown on the icon due to the more western track of this first low.

Chances will pop up everywhere all week

Its a very unstable set up with these heights no body should write off snow chances in this set up.

Glass half full were in a great position

Edited December 27, 2020 by Scott Ingham

[Methuselah]

30 minutes ago, Tim Bland said:

Some runs like Arpege have almost nothing for anyone now. Can’t remember such uncertainty at under 24hrs. May as well just watch the radar

The Lowestoft Lurker looks good. But then Arpege snowfall maps often do!

[bobbydog]

4 minutes ago, The BEAST From The East said:

Thanks for reply, so does it look like this time round it has or will?

It can take anything from a few days to a few weeks. The GFS is showing a complete vortex split in week 2. So... potentially... we could be seeing some classic charts showing very soon... 

[bluearmy]

Just now, Skullzrulerz said:

A bit misleading to say that it has very little support 

The majority do seem to remain below average but there is a "pack" that certainly does 

One to keep a eye on 

Given that we will have a cold environment established across W Europe, that breakdown pack does at least pose a decent chance  of a snow event (at worst transitional and at best messy lasting a day or two). That could deliver more snowfall than the colder clusters! 

[winterof79]

This my friends is highly likely at some stage and is a bi product of the formation of our own slack cold pool. If the small disturbances form it will be slow moving streamers galore. We had one such streamer that dumped 6" or more in a few hours of the Irish sea.

 

Now that would be some Sunday Lunch......

Edited December 27, 2020 by winterof79

[alexisj9]

2 minutes ago, The BEAST From The East said:

Thanks for reply, so does it look like this time round it has or will?

This time the troposphere is leading the way. A totally different senario. It's the high pressure segments, the strength of them, effecting the strosphere causing the warming, which is forecast to lead to the SSW. It will certainly help to stop things returning to climatology I should think. 

At least this is how I understand, what I've read, I may be wrong.

What I'm wondering what has made the difference. It certainly feels different some how.

[Anti-Mild]

5 minutes ago, Jon Snow said:

The world is changed,  I feel it in the water, I smell it in the air, etc etc..anyway, the ECM 0z ensemble mean is cold god dammit!

Nice LOTR reference! Here's hoping for some Pass of Caradhras type bilizzards, which is pretty likely were the ECM to verify.

[DanDorsetUK]

Nice wording from the Met Office on the app right now for my location Bournemouth. Chances all week by the sounds of things. Just seeing some flakes falling I'll be happy with. Will most definitely come down to Radar watch all week. Like a few posts have already mentioned this is a slow developing situation. Model disagreements will continue for some time while the SSW is cooking nicely. I still feel were on the brink of pretty major cold spell of weather right through January. 

[chionomaniac]

I’ve been watching every model run over the Christmas period and no major changes. Firstly, synoptically, the 500hPa pattern has always looked better than the 850,s it brought with it. Snow was always going to be marginal, and I think that most members realised that even this isn’t armageddon territory, there is still risk of seeing white stuff falling out of the sky in the coming days.

In my eyes, the start of the cold spell was always that. The starter. And it is the main course that follows this starter that I will patiently await. Whether or not this arrives before the forecast SSW remains to be seen, but I certainly wouldn’t look too far ahead in the output. Stick with the ensembles after day 6.

The critical day for an SSW was 10th Jan for me and looking at the latest GFS forecast at 10hPa we are more or less there

 

what is great to see is the split element following the displacement - how this then plays out trop wise in the heart of winter will be critical to the size and splendour of our main course. 

A scotch egg will never be enough for me!

Edited December 27, 2020 by chionomaniac

[Scott Ingham]

19 minutes ago, snowking said:

In the shorter term still great uncertainty around any snowfall potential tonight and tomorrow, but also worth keeping an eye on Tuesday, with another LP running down the western side of the country, some models (eg Icon and Arperge) swing this system into central areas - these are the sorts of features which you just can’t anticipate showing up until short notice, but make scenarios like this a fascinating watch

Good post! So much smowfall potential this week at short notice! All of this before it looks to become even colder the week after!