Model output discussion - Christmas approaches

[bluearmy]

said we needed to see the eps suite be consistent 

alas, the warmth is headed too far north for any error 

the chart on the left is the change from the 00z mean at day 9 T2 temps 

on the right is the 7/12 day T2 which is still decent but getting v close for comfort !

    
 

 

[LRD]

Just now, Radiating Dendrite said:

I would still caution that the snow is showing in FI. Let's get this down to 4 days out first before getting our metre sticks out!

That's true but what I think he means is that, whatever happens, at least we're not looking at a zonal train of strong high pressure over France into Central Europe, lows driving the pattern over Iceland and to our north and West/Sw'ly winds piling right into Russia, leaving us desperately looking for a SSW or signs of tiny height rises over Greenland or Oslo at 384 hours

[Ali1977]

As a mean at 192 that looks very winter storm esk ️

As do 216 and 240. Some historic snowfalls in these ENS I reckon 

Edited December 16, 2021 by Ali1977

[LRD]

ECM op is a WARM run and right at the top end of the suite days 9 and 10

A real split between cold and less cold in the ensemble suite though

Edited December 16, 2021 by LRD

[Lukesluckybunch]

wow the ECM op is sitting at top of the pack

[Malarky]

Just now, Lukesluckybunch said:

wow the ECM op is sitting at top of the pack

That’s pretty gobsmacking considering it wasn’t at all bad.

[Mike Poole]

ECM clusters, now where do you start?

T120-T168:

OK, so there are 6 of them.  All of them end up -NAO with some kind of heights into Greenland, including a full GH.

T192-T240:

It is a shame these aren’t NH view, but I think you can see that the vortex shredder option, which includes the op run, is Cluster 3.  All -NAO by the end of the time period.

T264+

Well, we don’t want cluster 1, others look OK but this is way way to far out in time to be relevant!

[SLEETY]

low pressure in these set-ups nearly always end up further south when it come into the reliable timeframe,ecm op probably one of the mildest runs for london ,when it comes out,everything still too far out anyway to be cetain of anything

[supernova]

Increasing chances of Christmas cold 

Cross model agreement for Atlantic low colliding with robust Greenie block and ensuing battleground 

Continental flow, low dew points, good chance (words chosen carefully) it'll be cold enough for snow somewhere over Xmas period 

Time for upgrades - significant detail still to be resolved - of course also still potential for shortwave shocker or slider positioning drama 

What's not to like? Merry Christmas fellow Netweatherers, not sure the festive chase for cold gets any more fun than this. Suggest you all chill your beans, open a can (or whatever takes your fancy), and enjoy the show. 

[Mike Poole]

Just now, Malarky said:

That’s pretty gobsmacking considering it wasn’t at all bad.

That’s for London, and it well and truly missed out on the cold on that ECM op run.  

[Cold Winter Night]

2 minutes ago, bluearmy said:

said we needed to see the eps suite be consistent 

alas, the warmth is headed too far north for any error 

the chart on the left is the change from the 00z mean at day 9 T2 temps 

on the right is the 7/12 day T2 which is still decent but getting v close for comfort !

    
 

 

Glad you be beat me to bringing the bad news.
The Ensemble has shifted quite a bit to milder in the days before Christmas.
I saw the Dutch meteogram and had to check if it really was the 12z ENS, alas, it was.

Not too happy with the clusters either.
High goes NW too far, too fast.

[swfc]

1 minute ago, Valleyboy said:

In these situations, you will find things trending south closer to the time, sometimes the Uk misses out, with the snow ending up over the channel isles.  Too early to predict where the snow will fall this far out.  Snow forecasting this far out is rarely correct.

Yes I understand the set up"i grew up in the 70s and have studied exceptional weather events"including fronts moving in from most directions. The classic easterly is a more northern England south. This isn't a straight forward Eastern cold easterly. My point is on one run the cold can't be too far north. Come Monday we could be in a westerly that's how quick things change. I'd bet we're not but the classic moving South imo is generally in the slider scenario 

[I remember Atlantic 252]

1 minute ago, SLEETY said:

low pressure in these set-ups nearly always end up further south when it come into the reliable timeframe,ecm op probably one of the mildest runs for london ,when it comes out,everything still too far out anyway to be cetain of anything

Aye, agree with this, my guess is any snow 24th to 27th will be S of the M4, with fronts not reaching far enough north, staying cold and dry

[swfc]

10 minutes ago, bluearmy said:

said we needed to see the eps suite be consistent 

alas, the warmth is headed too far north for any error 

the chart on the left is the change from the 00z mean at day 9 T2 temps 

on the right is the 7/12 day T2 which is still decent but getting v close for comfort !

    
 

 

Thanks for that blue. May temper the current frenzy

[Man With Beard]

58 minutes ago, Ali1977 said:

This screams decent longevity of the cold spell , and she’s loads of snow 

This is reminiscent of a NH profile after an SSW. Have I missed something? Has there been one?

[Ali1977]

12 minutes ago, bluearmy said:

said we needed to see the eps suite be consistent 

alas, the warmth is headed too far north for any error 

the chart on the left is the change from the 00z mean at day 9 T2 temps 

on the right is the 7/12 day T2 which is still decent but getting v close for comfort !

    
 

 

I thought the ECM was very good, and it was actually on the warmer side of the pack so there must be much better - why are the EPS not so good then?? Or am I getting this wrong?

Edited December 16, 2021 by Ali1977

[swfc]

5 minutes ago, I remember Atlantic 252 said:

Aye, agree with this, my guess is any snow 24th to 27th will be S of the M4, with fronts not reaching far enough north, staying cold and dry

OK wel see but the cold boundary is very fickle 

Edited December 16, 2021 by swfc

[bluearmy]

2 minutes ago, Cold Winter Night said:

Glad you be beat me to bringing the bad news.
The Ensemble has shifted quite a bit to milder in the days before Christmas.
I saw the Dutch meteogram and had to check if it really was the 12z ENS, alas, it was.

Not too happy with the clusters either.
High goes NW too far, too fast.

Basically the suite moves everything too far north (as illustrated in the op).  It’s still within a tolerance which is going to be more than ok. We are seeing the pendulum swinging. Today has been a decent day for the cold spell but highlights that we still have a fair way to go yet on pinning things down. 
 

what we don’t want to see tomorrow is any more movement north and west on the trough - we need some correction south and east 

[Lukesluckybunch]

6 minutes ago, Mike Poole said:

That’s for London, and it well and truly missed out on the cold on that ECM op run.  

that has to be a positive sign

[Man With Beard]

8 minutes ago, Mike Poole said:

ECM clusters, now where do you start?

T120-T168:

OK, so there are 6 of them.  All of them end up -NAO with some kind of heights into Greenland, including a full GH.

T192-T240:

It is a shame these aren’t NH view, but I think you can see that the vortex shredder option, which includes the op run, is Cluster 3.  All -NAO by the end of the time period.

T264+

Well, we don’t want cluster 1, others look OK but this is way way to far out in time to be relevant!

Mindboggling set of Greenland Highs at D7, Mike. You can go through three winters with seeing that once!

[LRD]

1 minute ago, Ali1977 said:

I thought the ECM was very good, and it was actually on the warmer side of the pack so there must be much better - why are the EPS not so good then?? Or am I getting this wrong?

The mean line on the 850s graph is definitely warmer than this mornings meaning the suite has trended north along with the op, although the op seems at the extreme end of that

Could move back south tomorrow

Some of the clusters has the Greenland High almost too north for my liking. How ironic after we were worried, earlier in the week, that it would sink before it got to a decent latitude!

[Cold Winter Night]

4 minutes ago, Ali1977 said:

I thought the ECM was very good, and it was actually on the warmer side of the pack so there must be much better - why are the EPS not so good then?? Or am I getting this wrong?

If the pack is warmer, being on the warmer side is not as good as when the pack is colder.

We don't want the High moving too far NW for us to benefit, but that is what the EPS is favouring this 12z.
Can shift back though, the developments going on are so complicated, details matter.

Edited December 16, 2021 by Cold Winter Night

[bluearmy]

1 minute ago, Ali1977 said:

I thought the ECM was very good, and it was actually on the warmer side of the pack so there must be much better - why are the EPS not so good then?? Or am I getting this wrong?

There are six clusters - just too much uncertainty 

the ec uppers are not that far from the mean until after day 9 in London . 

[SLEETY]

Wait until everything gets into reliable timeframe before worrying if  its too far North,maybe all models should end at 168 hours like ukmo,save all the  heartache in here every few hours!

[Mike Poole]

2 minutes ago, bluearmy said:

Basically the suite moves everything too far north (as illustrated in the op).  It’s still within a tolerance which is going to be more than ok. We are seeing the pendulum swinging. Today has been a decent day for the cold spell but highlights that we still have a fair way to go yet on pinning things down. 
 

what we don’t want to see tomorrow is any more movement north and west on the trough - we need some correction south and east 

Having watched the models chase this setup over the last few days, I’m not on board with the idea that suddenly from 0z to 12z, this high is going so far north it gets into orbit!  (Yes I know that is not possible , it’s a metaphor).  For once I will welcome the 0z runs with their more conservative zonal bias!