Model Output Discussion - Into Winter

[Harveyslugger]

7 minutes ago, Ali1977 said:

So far the runs have downgraded snow chances in the south midland and down towards the M4 - although the BBC still uses the mornings ECMs graphics with everything much further south. I imagine we’ll be waiting till tomorrow lunchtime for it to firm up. Either way I think some people will be getting substantial snow, anyway from the M4 to Scotland

What's about south Wales 200m ASL?

[Mucka]

That GFS Op went against the ensemble mean by 96h as does the control in being too progressive.

By 120h the difference against the mean is a bit of a red flag. 

GFS Op V GFS mean 120h

[Ali1977]

3 minutes ago, Harveyslugger said:

What's about south Wales 200m ASL?

Looking good there I’d say

[bluearmy]

2 minutes ago, Mucka said:

That GFS Op went against the ensemble mean by 96h as does the control in being too progressive.

By 120h the difference against the mean is a bit of a red flag. 

GFS Op V GFS mean 120h

Not really in agreement mucka - I wouldn’t expect the mean to catch the slp detail in a situation as we have next week. The upper pattern looks pretty solid agreement. I’d be quite content that the gfs op is well within tolerance of its ens 

[Battleground Snow]

This is far from resolved...

[TSNWK]

4 minutes ago, Battleground Snow said:

This is far from resolved...

how on earth can Perb 7 be so different than the Op at 5.5 days - yes I get that adjustments to starting conditions are applied to in essence stress test the OP - but come on the difference is to wild for such a short timelead

Edited December 1, 2023 by TSNWK

[Mucka]

1 minute ago, bluearmy said:

Not really in agreement mucka - I wouldn’t expect the mean to catch the slp detail in a situation as we have next week. The upper pattern looks pretty solid agreement. I’d be quite content that the gfs op is well within tolerance of its ens 

The longwave pattern does suggest a breakdown and I already stated that in a previous post, but here we are discussing how far E and how quickly the Atlantic pushes and the fact is the GFS Op is extremely progressive in pushing milder air NE.

It is unusual for the Op to be so out of kilter with its ensemble suite in such a short a timeframe 96/120h and it is very much at the progressive end of the scale even if we disregard the signal mean being distorted with the more blocked runs that you are dismissing.

How far NE the Atlantic pushes from any breakdown matters if we are considering the possibility of blocking returning before mid Dec

[LRD]

2 minutes ago, TSNWK said:

how on earth can Perb 7 be so different than the Op at 5.5 days - yes I get that adjustments to starting conditions are applied to in essence stress test the OP - but come on the difference is to wild for such a short timelead

The op and control follow each other. I'm sure I read it on here that you can put added confidence in an op solution if the control is following it (I know ECM now combines op and control but GFS doesn't as far as I'm aware)

[northwestsnow]

We need a last minute winner ie EC trends 50 miles south with the low Sunday..

[Cambrian]

12z ops for day 5 from GFS, GEM, UKMO and ICON. Some noticeable variation but around the same central theme, introduction of a flow from the south to southwest. Greater divergence thereafter. 

   

Hah, those saying it’s going to get milder! It’s like stopped clock syndrome, twice a day you’re bound to be right - unless, that is, it’s one of the models that goes out four times a day!

Ah, the old ones are the best ones.

Let’s face it though, to keep it all in perspective, plenty of people said it wasn’t likely to turn cold at all. -5.4 degrees here this morning, got just above freezing for three hours from 11 til 2, -2 as I write. Glad I’ve done all my outside work, although the recent nights have been well worth getting wrapped up for an outing. 

It’s the weather, and the beauty of it is that it will always keep us guessing . Have a great evening, I’m going to watch films and drink loads of wine  before heading out to no doubt once again be gobsmacked by the awesomeness of the night sky. 

[northwestsnow]

UKMO 168

The entrenched cold across Scandy under threat ..

Edited December 1, 2023 by northwestsnow

[BarnetBlizzard]

Mean GEFS 12z has more heights into Scandi at at 162h compared to 6z. Some similar to Icon 12z in that respect.

[TSNWK]

2 minutes ago, northwestsnow said:

UKMO 168

The entrenched cold across Scandy under threat ..

this is next big concern - I think we can safely say that is 95% on Milder  for UK middle of next week onwards - we need it to stop there though and hope that we dont lose SCandi cold pool.. 

Impact of which is illustrated around day 12 on 12GFS - whereby synoptic wide it looks ok, but there is no cold to tap into because its all be flushed out for Scandi.

[Ali1977]

I like the last line of the METO long range , a chance of a longer cold spell later into Dec!! Guessing that’s MJO related!!

anyway, cmon ECM

[Dennis]

Good signs from strato too soon for the winter

see topic 

 

Edited December 1, 2023 by Dennis

[LRD]

9 minutes ago, northwestsnow said:

We need a last minute winner ie EC trends 50 miles south with the low Sunday..

Trouble is we're 2-0 down so need 3 last minute strikes!

[sheikhy]

On ecm we need that low on monday to be further south and then we can build from there hopefully!!!

[northwestsnow]

5 minutes ago, TSNWK said:

this is next big concern - I think we can safely say that is 95% on Milder  for UK middle of next week onwards - we need it to stop there though and hope that we dont lose SCandi cold pool.. 

Impact of which is illustrated around day 12 on 12GFS - whereby synoptic wide it looks ok, but there is no cold to tap into because its all be flushed out for Scandi.

I think even cold radicals like me on here accept a period of Atlantic dominated weather post tues/wed,the key question of course is how long ..

The back ground drivers seem relatively positive but thry have before ,and it doesn't always work out for us.

Overall, really happy we've had frosty nights here since Monday, killing all those nasty airborne bugs!!

I'm thinking a good week possibly a bit longer of +NAO hopefully the MJO does its thing and help buckle what will likely be a strong jet .

Edited December 1, 2023 by northwestsnow

[Frosty.]

6 minutes ago, BarnetBlizzard said:

Mean GEFS 12z has more heights into Scandi at at 162h compared to 6z. Some similar to Icon 12z in that respect.

Being realistic, I think the latest mean charts are indicating a gradual change towards less cold / milder and more unsettled next week..I wish it wasn’t so, as does yoda!  

[LRD]

5 minutes ago, Ali1977 said:

I like the last line of the METO long range , a chance of a longer cold spell later into Dec!! Guessing that’s MJO related!!

anyway, cmon ECM

Yes, that was an interesting little sign off from the Met!

[BarnetBlizzard]

  

haha Yoda wants nothing more than a full blown Easterly! I'm definitely not saying an Easterly is likely but there are just some small signs that the Scandi high could have more influence on weather in around 8-10 days time then is shown on GFS OP/UKMO. 

[northwestsnow]

Interesting Exeter referencing late December,potentially.

Certainly EC46 will be interesting over the coming days,not only trop but strat related.

 

[Premiere Neige]

31 minutes ago, Battleground Snow said:

This is far from resolved...

Uncertainty begins in 2 days time it seems...

[northwestsnow]

APREGE Sunday

[Mark wheeler]