Both could very well turn out to be true, of course. (December being above average but also being the coldest month of the winter.)

I guess it depends on when you regard the 'form' as starting. It was only recently that blocked runs were being thrown out quite regularly.

The only obvious conclusion at the moment is that the behaviour of the atmosphere more than a few days ahead is proving difficult to predict.

But this has been my point for a week now. 

We have lots of blocking... but the positioning and lack of cold air is just wasted

Its starting to become a bit of a problem we need to flush away... its blocking mild atlantic air but its blocking the cold air too...

Possibly!? The models have been playing around with this idea of a warming ot SSW occurring over Siberia and pushing into the Arctic region for a while now at the end of FI:

Could all change but the theme has been consistent IE- seeing a warming of the stratosphere from the middle of December!?

That looks like the typical gentle warming that occurs every winter; certainly it doesn’t fit the definition of a SSW, which is for much greater warming in just a couple of days: it’s like a sudden shock being injected into the stratosphere which then propagates down into the troposphere.

I think a pattern change yes, flushing it with the Atlantic can quickly turn into an 8 week toilet of wet, wind and mild.

What certainly does need to happen is troughing into the East - we need a Greenie and go from there.  Ural Highs aren't really getting us anywhere further than seasonal.

T/O.

https://www.wetterzentrale.de/en/show_diagrams.php?model=gfs&lid=ENS&var=2&bw=1&geoid=49069

Doesn’t get much worse than this.

Jetstream continuing to throw a big loop to the S in the Atlantic before  weak N'ly return over W Europe and as the week progresses more emphasis on the S'ly stream. Another loop forms  to the S on Mon 14th followed by a chaotic week with bits of jet flying everywhere, but always with the more coherent branches to the S of UK and often into the eastern Med.

GFS - Any prediction of HP shown yesterday has disappeared so confidence must remain low. For this week, a trough of LP pokes in from the NW and is renewed from time to time by more Atlantic input. Next week more movement, with LP passing Scotland Wed 16th with SW'lies for most and another LP in SW approaches with S'lies Fri 18th. These two eventually link up with major LP over Russia and on Wed 23rd this set-up feeds E'lies from a cold source over southern UK and HP 1040mb Orkney (cf Retron's comment above)

GEFS - temps rising slowly to a degree or two above norm around Tue 15th and mean of runs falling back to just below norm Wed 23rd (but the op run is a notable cold outlier, as above, 10C below). Small amounts of rain throughout plus a few extra spikes in N Scotland at first and in SW England later.

ECM - tends to keep LP out to the NW though it does promote a trough S'wards Sat 14th, and then back to LP off NW Scotland Tue 15th. For the last couple of days of the run, pressure pattern over NW Europe has no real definition.

Perhaps they should be changing it every 6 hours in line with the GFS? 

Malcolm
Wakefield & Gothenburg, SWE

Oh, it can be a lot worse than this; as you well know.

Synoptically the Op run isn't that far out of line with a good few ensemble members; I was pleasantly surprised to see how many have blocked or largely blocked evolutions and how many feature a strong Arctic high. Of course, getting all the pieces into the right place is the issue: the Op does that but several others get close.

Or maybe your crystal ball isn't as good?

GFS 00z mean 500 hPa anomaly chart at Day 10 shows quite a decent signal for higher pressure to our north and NE.

6z gfs  not as spectacular as the 0z  but still ends with significant  blocking again . We need some luck as ever in the UK but the Christmas period is looking pretty good for some very seasonal weather. Best chance of a proper white Christmas for many a year.

Lots of blocking in the gefs 6z not always in the right place for UK though but no sign of anything zonal.

P18 ,P23,P26, P27 and P28 are very cold. 

P18 would surpass any severe spell since the early 90s IMO.

As in any winter model watching season, it’s all about sifting the genuine signals from the noise. You’ll always get a smattering of Stella runs in any ENS set, especially now there are 30 GFS perturbations and the ECM available. The trick is to identify if any of the more ‘favourable’ solutions (and remember, the Operational is always preferred to any of it’s ensemble siblings in isolation) are a genuine sign of a particular synoptic forecast or just ripples on the lake. And to assist that process you need to look at the background signals that may be influencing those solutions - MJO, AAM, u-wind trends, strat temps, etc. This is where you need to make judgements and assign a degree of confidence on whether the extended range offered by any particular model seems plausible or not whether it makes sense given the above - and other - known parameters. The computers of course take these and many other parameters into account to churn out their solutions but it’s rare to achieve above 85% accuracy at 5 days and much less at 10 days so anyone saying it will definitely be this or that in two weeks is at best guessing. 
The best even a hugely experienced forecaster can hope to achieve is an ‘idea’ of the set up in two weeks and that’s where means can be useful - to spot rough trends. That’s why I council against taking individual runs in isolation. It’s nice art but very unlikely to be a solution.

Now I’ve forgotten where this post was heading 😂☺️

P18 is indeed a beauty.  

I just think there is room for optimism at the moment . ECM ensembles have a lot of blocking in the 11 -15 day zone. Gfs seemingly also picking up this signal now. It wouldn't surprise me if the output gets significantly better over the next couple of days.