The ECM12z is really no worse than the 0Z in terms of the large scale synoptic situation, which is really all we should care about at this sort of range.

Wouldn't describe it as either an upgrade or a downgrade.

The GFS 12Z is undoubtedely an upgrade on the 0Z and 6Z however.

216 h shows what Retron means about the importance of high pressure around Iceland. It's there on GFS, and bingo for the south,

But on ECM it's further north, over Greenland, and cold rain for the south:

Op looks pretty wet in the south across Xmas/Boxing Day. Fine margins

Lots of close but no cigar for the south, with the exception of the GFS. 

Indeed, think chances of a pleasantly seasonally dry, sunny and frosty Christmas for us southern contingence is disappearing faster than the contents of Bill Cosby's drink cabinet.

Agreed.  I made the point this morning that we were talking about a few hundred miles either way at 8-9 days out; nothing has changed.

It could still be anything from a mild, wet Christmas through to bone dry in a biting easterly, depending on exactly how the push of mild air interacts with the cold.  But I’d have more enthusiasm if the cold air was already in place when the battle commences; assuming there is a battle.

Makes for tremendous viewing though, just fantastic to see it all unfold!

Models really are all over the place.  Anyone's guess for Christmas atm. 

Ar a range of 7 days plus, that's all going to change anyhow....probably for the worse.

It looks marginal in the south as the LP has mild air associated with it on the GFS / ECM / ICON / GEM

What I see is a blocked pattern with strong Northern HPs floating around and over the UK

Stav on BBC presents an encouraging weekly plus outlook, with cold winning in the run up to the holiday,  and in the daily forecast talks about a potential 'battleground' in the S over the holiday period.

Does mention the HP moving to Iceland. There was a nice Iceland-Scandi link in 2010 at one point. The Greenland HP always seems too far away to me to maintain influence in its waxing and waning.

What is weird is that if we had a raging Atlantic (touch wood fast), the models would be pretty predictable out to 7 days plus. When you get a block and the threat of cold, the models go very wobbly, and getting more than 3 days accurate seems beyond them. Anyone fancy an explanation of that?

The current output seems almost like a repeat of the pattern that we saw a few times during January and February last:

Excellent fun model watching at the moment, really addictive made even more so with Christmas fast approaching. One thing we can say for certain is that at t216 hours away no one knows what the weather will be like on the big day not the models, met office no one. With lows that have not even spawned yet the track and how they may disrupt or not will take at least another 4 to 5 days to determine with any real confidence. 

Compared with what we were looking at a couple of days back the heights that build north in the next week are impressive and do not look like going anywhere fast and with this in mind the chances of cold and wintry weather look like the form horse to me whether that be on the big day itself or delayed a little into the Christmas week. 

Great stuff role on the 18z.

🤔🥴 but not 🥱

https://www.wetterzentrale.de/maps/ECMOPNA12_240_34.png 

This is all 'just for fun' theory, but that same region saw some very high temps at the same point in the summer season (late June) and that coincided with a prolonged very warm period of weather in the following weeks/months on this side of the Atlantic. Whether connected or not, I don't know but would be interesting to see if similar occurs later this winter (Cold PNW followed in the weeks/months by a cold NWE).I honestly don't think we have broken free of the pattern that became entrenched during the summer last year. The lack of any real wind for example was remarkable during the Summer and Autumn (and I'm only speak from an Irish perspective, but I imagine a similar trend in the UK) and this trend continues unrelenting into this early part of Winter so far. That high pressure zone that set itself over the NE Atlantic region during mid-July really jarred the mean synoptic pattern and its legacy is still with us to this day.

In fact they’re not all that predictable, in terms of precision. Part of it is an illusion because we don’t put every piece of model output under intense scrutiny when that’s the pattern.

But the prevailing flow of weather systems is from the western quarter (SW to NW), and tends to be more straightforward than a pattern where there’s a meeting of two distinct air masses, with a turbulent flow from different directions, and that interaction is in our vicinity.

I still find it surprising how well the models manage to deal with such situations; the physics involved is complex.

Looking at ECM are we really that far off a Jan 1881 set up...if cold could get established for a day or two...with the mild air nearby a real deep low could be present....fine margins indeed...