Model Output Discussion - Colder spell ending, what's to follow?

[BLAST FROM THE PAST]

ECM looks very good to me.  Want to see that solidify.  Cold Christmas about to happen from that run.

cold air digging in and the low to SW is being squeezed and flattened...nice channel runner

 

BFTP

Edited December 12, 2020 by BLAST FROM THE PAST

[blizzard81]

1 hour ago, swfc said:

Yes it's built better than I thought. Anywhere near that would be fine. Is it me or is it like "one flew over the cuckoo's nest" on here this evening "

Ha ha I'm with you mate. It definitely felt like that earlier. I'm still very optimistic about Christmas week. There's been nothing generally on the models thus far to make me change my mind

[Tim Bland]

12 GEFS show the op was on the mild side in FI thankfully. Average for Xmas day was -2.2 (t850) with around 25 % cold enough for snow (-5) 

[blizzard81]

The more I look at the day 10 ecm op chart, the more I like it . 

[Griff]

1 minute ago, blizzard81 said:

The more I look at the day 10 ecm op chart, the more I like it . 

Wait until you see the monkey face... 

[blizzard81]

4 minutes ago, Griff said:

Wait until you see the monkey face... 

I've really tried but I just can't see it lol  

[blizzard81]

That is a decent day 10 mean from ecm and goes with the gfs mean. All good

[Griff]

19 minutes ago, Tim Bland said:

12 GEFS show the op was on the mild side in FI thankfully. Average for Xmas day was -2.2 (t850) with around 25 % cold enough for snow (-5) 

An attempt at seriousness and trying to avoid my predisposed confirmation bias, but looking at GFS runs beyond day 5 are enough to induce manic mood swings in both directions, often at the same time. 

The ECM, ukmo, and dare is say it my beloved gem all seem to be less prone to jumping overboard and seem more steady and consistent. 

As other probably wiser members have said previously, there definitely seems to be an issue with quality vs quantity. 

That said, this winter seems to have a lot of signals to complicate the issue, yet it's a bit too easy to refer to defaults which seem to happen more regularly on the GFS. I'm not convinced any model is coping too well beyond any given week ahead. 

[Griff]

7 minutes ago, blizzard81 said:

I've really tried but I just can't see it lol  

Apologies off topic I'll stop after this. Sorry

[MATTWOLVES 3]

At first glance the 10 day ECM mean is above the op on those 850s,but not to worry folks I've just viewed the extended out to day 14, and the mean is coming down several degrees and more in line with the op, so it's not quite the outlier it looked at first glance... Could be a tad cold for Xmas.. That's the plan and current guidence anyway. 

@Mike Poole thanks for the heads up on that Winter watch programme, covering the 1963 Severe Winter... Its on the BBC i player folks... Well worth a watch.. Enjoy your evenings. 

[Decemberof2010]

No random ensembles from me today. Day 10 (again) on the ECM does look decent and a fair few GEFS look good too. All is not lost as I haven’t yet heard that well known winter straw clutch of

’anyone seen the JMA?, I’ve heard the Met hold it in high regard’

So here is the JMA 192. Heading the way of ECM?

 

Lets hope for a continued improvement tomorrow and maybe if you’re all lucky I will post up some ridiculous cherry picked charts JFF of course

[Jason M]

2 hours ago, Frosty Winter said:

Appreciate that, but posting one timestamp from a singular ensemble member nearly ten days away is about as much use as a chocolate fireguard.

In fairness, if we apply that as a test just about everyone on this thread would have been banned years ago. 

[BLAST FROM THE PAST]

34 minutes ago, blizzard81 said:

The more I look at the day 10 ecm op chart, the more I like it . 

Because it’s a beauty....I hope that is very similar to fruition

 

BFTP

[Jason M]

1 minute ago, BLAST FROM THE PAST said:

Because it’s a beauty....I hope that is very similar to fruition

 

BFTP

Quite a few GEFS have looked similar, but unfortunately the winter killer is present on this chart (as per many of the GEFS). Heights are centered around Iberia and when that's the case we can completely forget anything cold away from northern Scotland. IMHO the most likely outcome would be that 24 hours later the pattern would already be flattening.  

[Tim Bland]

4 minutes ago, Jason M said:

Quite a few GEFS have looked similar, but unfortunately the winter killer is present on this chart (as per many of the GEFS). Heights are centered around Iberia and when that's the case we can completely forget anything cold away from northern Scotland. IMHO the most likely outcome would be that 24 hours later the pattern would already be flattening.  

Do you not think this low to the south west would assist if it went through the channel. Even better it ends up further south and heads south east? 

[Daniel*]

21 minutes ago, MATT said:

At first glance the 10 day ECM mean is above the op on those 850s,but not to worry folks I've just viewed the extended out to day 14, and the mean is coming down several degrees and more in line with the op, so it's not quite the outlier it looked at first glance... Could be a tad cold for Xmas.. That's the plan and current guidence anyway. 

@Mike Poole thanks for the heads up on that Winter watch programme, covering the 1963 Severe Winter... Its on the BBC i player folks... Well worth a watch.. Enjoy your evenings. 

There’s pretty good agreement for more seasonal temperatures just in time for Xmas.

 

[Nick F]

Hints from the 12z EPS extended mean of amplification upstream, starting around D10 over the NE Pacific, as the Aleutian trough amplifies teleconnecting to amplifying ridge/trough across N America which eventually leads to amplifying ridge over the N Atlantic around D12. 

Day 10-15 EPS mean

Day 15 EPS mean

[Griff]

10 minutes ago, Daniel* said:

There’s pretty good agreement for more seasonal temperatures just in time for Xmas.

 

Also supported by latest CFS (but I don't hold that against it) 

[Jason M]

11 minutes ago, Tim Bland said:

Do you not think this low to the south west would assist if it went through the channel. Even better it ends up further south and heads south east? 

That's just riding the polar front. It is likely headed NE to give us a splash of cold rain (if you run the ECM chart sequence it shows this). 

[bluearmy]

24 minutes ago, Nick F said:

Hints from the 12z EPS extended mean of amplification upstream, starting around D10 over the NE Pacific, as the Aleutian trough amplifies teleconnecting to amplifying ridge/trough across N America which eventually leads to amplifying ridge over the N Atlantic around D12. 

Day 10-15 EPS mean

Day 15 EPS mean

My disdain for single cluster eps clear from comparison of that 10/15 day mean and the updated single cluster ?

 

[blizzard81]

8 minutes ago, bluearmy said:

My disdain for single cluster eps clear from comparison of that 10/15 day mean and the updated single cluster ?

 

Why do they do this one cluster shinanigans every now and then?

[blizzard81]

A clear trend downwards from days 11 to 15 on the latest ecm debilt ens. UK would see this a couple of days earlier due to the cold coming in from the north west. 

Edited December 12, 2020 by blizzard81

[stodge]

Evening all

A fairly downbeat assessment from me yesterday based on the evening's output but it's another day and some of the background signals continue to offer cause for encouragement for those seeking cold, snow or just some interesting synoptics.

12Z GEM: - by this Thursday (T+120), the first LP has pushed just to the north east of the British Isles and the trough extends back to the main LP far to the west. A SW'ly airflow keeps it mild and with a transient ridge we should be enjoying a fine day. By T+180, there have been some interesting developments. The main LP has cleared to the NE and a PM airflow from the NW is moving down through the country but there's not much happening in the Atlantic with the next instabilities far to the south west and the Azores HP trying to ridge in to Iberia and North Africa so not sure where this is going.  However, a new LP develops and swings NE pulling the Azores HP into Iberia so the mild flow remains but there is a  pronounced Atlantic ridge behind and heights remain over Greenland so it's a tantalising end to the run.

12Z GFS - GEM hints at a break in the flow and some amplification at T+240 - let's see if the OP is in a similar mood. At T+120 only marginal differences with GEM but perhaps the most interesting is a more defined ridge from the Azores HP through central and southern Europe. By T+180, some differences emerging against GEM - the main LP remains to the NW but with secondary features swinging toward Southern Britain bringing more pronounced periods of rain and strong winds. A further deepening LP in mid-Atlantic adds to the mix with the core of heights over SE Europe.  By T+240, we have a PM airflow as the LP moves across just to the north of Scotland with a pronounced trough passing through eastern and southern Britain at that time, Some amplification upstream but not as pronounced as on GEM.  By T+312, the Christmas Day BBQs looks safe with HP over France and a mild or very mild airflow with LP held well back in the Atlantic. T+384 is every cold fan's worst nightmare. Perhaps the only positive at the end of FI is another warming setting up which looks more extensive then the warming due at T+192.

12Z ECM - the last chance saloon tonight? It'll be interesting to see if it follows GEM in any way. T+120 looks pretty similar.  By T+192, the main LP is just off NW Scotland and the cooler PM airflow is moving in. An LP forming in mid-Atlantic and an HP developing to its north-west are interesting but I suspect it won't help us.  To be fair, T+240 is more encouraging than I suspected - the LP is taking a more southerly track with the HP less inclined to ridge NE and could we be seeing the HP building more into mid-Atlantic? I'm not 100% sure where the evolution's going from there.

Elsewhere, 12Z Control is a much colder option than the OP and at T+240 isn't too far removed from ECM at the same point. 00Z Parallel ends anti-cyclonic with a impressive cold wave coming out of Siberia but which probably wouldn't reach western Europe.

Conclusion: - just a few straws in the wind tonight for cold fans. 12Z GFS OP is a horror story apart from the 10 HPA warmings. Both GEM and ECM tease and tantalise with T+240 evolutions and the 12Z Control wouldn't be wholly unwelcome. One or two mused the reversion to a milder spell might last 7-10 days at most and that's not inconceivable but as always we need all the pieces to drop kindly. One thing in our favour is a quiet-ish Atlantic and a PV which still struggles to show the robust characteristics of some recent winters. 

 

[Man With Beard]

12 minutes ago, bluearmy said:

My disdain for single cluster eps clear from comparison of that 10/15 day mean and the updated single cluster ?

 

Yep, clusters are useless tonight. The mean ECM D10-D15 reveals the reality better - a big shift on the individual ensembles, with at least 50% now showing a useful Atlantic ridge, plenty of which could provide a path to wintry weather by Christmas Day. Being a big shift, though, makes me a little wary of starting a bandwagon though. Will be watching the 00z ensembles with interest!

[Man With Beard]

6 minutes ago, blizzard81 said:

Why do they do this one cluster shinanigans every now and then?

I can only think it's because their supercomputer can't see any distinct groupings. Bit surprised tonight though, as when I scrolled through the 51 members individually, there seemed a big grouping going for a mid Atlantic high