I think UKMO is pulling that low further West:

http://www.meteociel.fr/ukmo/runs/2014122312/UW96-21.GIF?23-17

Full of potential:

http://www.meteociel.fr/ukmo/runs/2014122312/UW120-21.GIF?23-17

Before then some snow possibilities.

GFS parralel is much better

Im again ignoring the GFS.

The trend has been to keep pushing the high slightly N and W.  Will the trend continue on the ECM?

UKMO 96 is cold and wet and windy.

120 UKMO is colder and wintry but drier.

Than the GFS at modelling in general?

Here is the 138 GFSP chart. Quite tasty.

And between 96 + 120 snow potential

Too much forcing of the northern arm of the jet, or it would have been a classic. Still room for improvement, but GFS needs to come into line

But I would accept the UKMO run if I had to take it now. At least it would be a proper cold snap. Something we never had at all last year

No just this run, the parrallel 12z at least tries to build a ridge in spite of a raging northern jet

Yes the UKMO is a classic run IMHO and lots of interest.  

That is the previous run. GME only out to +60 so far

It's ccertainly no classic  but compared to the GFS I guess it is. At least it will be dry and frosty but a long way of delivering deep cold and snow, well except for the far SE perhaps.

If the low had slid cleanly south on the UKMO run rather than splitting off a feature that runs NE to Svalbard, this run would have manages to combine GFSP's 'sausage from Scandinavia' with a more amplified upstream pattern, which would be very good going forward.

Instead the above suggests a UK high with nowhere to go really. Thanks to the day 5 easterly and quite probably a bit of lying snow, the surface cold would be substantial, and any incursion of warmer upper air temperatures would likely lead to a case of persistent freezing fog.

As for the GFSP run, the sausage high means a longer lasting easterly but the upstream pattern remains similar to the previous run with too much energy running N/NE to allow for a decent undercutting low from the Atlantic. For days 8-10 of this run it will all come down to the angle of the jet as the split has ceased to exist. Doesn't look as good as on the 06z as of +180 hours.

The disrupting low on the SW tip of Greenland is what really sets the UKMO run apart at just 5 days range and the catalyst for that is already in place by day 4, as the jet coming off the U.S. angles far south enough to become entangled with the low west of the Azores:

The past two ECM runs have been doing this sort of thing but with the jet not quite as far south. All eyes on the 12z ECM to see if it adjusts that south or not... and that's before we even get to the sliding low on our side of the pond!

I have to say - if the METO comes off - i doubt it will be anymore than what we have had already - cold rain, with marginal snow for areas above 300m in Northern England.

Theres just not that much cold air wrapped up in the LP... and the source its pulling the cold air from, isnt that cold. Add in the warm sector thats being sucked up, and - as you can see from the GFSP is a big fat round green LP. cold wind and rain anyone?

I just dont think it cuts the mustard at this stage.

There just seems to be a lack of cold air vs UK at the moment. Ordinarily the LPs that have hit us recently would have provided lots of interesting weather to the likes of Manchester. But the Peaks remain brown and mild records continue to be threatened.

Shall I carry on being the new found Model Output Monster?

I've noticed that the ol' skool GFS is still sticking to it's guns by suggesting the weekend's low continuing to move more or less in an eastwards direction and we go back into the mobile westerly regime shortly afterwards (much like what we are in right now).

And there's GFSP (and the other models) sticking to their guns with that low moving in a southerly direction, skimming along the eastern side of the UK and filling in quite quickly in doing so.

The former would not bring any form of wintry precipitation to us whatsoever, whereas the latter would actually give us something of a chance.

I would be quite impressed if the ol' skool GFS option does turn out to verify on the moment and thus it would be a shame to lose the model in the new year!

But those heights? Still too much of a westerly component about them on both outputs with not enough northwards ridging, that polar vortex - while not as intense as this time last year - just won't budge.
   But since high pressure will build back over the UK in some form or other as we go into the first half of next week anyway, hopefully it should at least stay dry for long enough to make for comfortable New Year Celebrations at London.

I suspect the ECM will go onto showing a completely different outcome beyond this weekend's low pressure event, just to keep us on our toes.

PS: It's true that I tend to be a GFS person, in case anyone is wondering. I've never really been a true follower of the ECM when it comes to medium range predictions, but that's just me being me.

I'm pretty sure that if we had a situation whereby the GFS was showing runs that were favourable for cold and the UKMO and ECM runs at the same time were going for milder scenarios, many of us here would not be placing a great deal of faith in the GFS. I have always been rather reluctant to trust GFS on its own, certainly since the infamous phantom easterly fiasco in February 2007 which ECM and UKMO never bought into seriously.

...unless you look on Meteociel which seems to have fast access to all the model output for some reason. I've only just looked at it and you know what, it is a very interesting run indeed:

The two shortwaves never really phase and the one from Greenland just takes off NE while it's southern neighbour dives SE, and that works out nicely for an easterly as the separation is sufficient for the sausage high, so a similar outcome to GFSP in that regard... but a very different story in the Atlantic as the jet exits the U.S. about as far south as it does on the UKMO 12z op run, leading to enough trough disruption for jet behavour conducive to an undercut.

As if that wasn't enough, the jet pattern at +132 hours looks about right for a strong undercut of low heights.

I wonder how close to that UKMO makes it... it could be more promising than I have been thinking.

Is it just me or have the models got less confident since this morning about the low?

GFS sends it to the east to create a northerly

GEM does a slider and sends it to the south

NAVGEM has the low sit right ontop of the country and then build a scandi high

GFSP brings the low south but the parameters don't support snow and by Sunday temperatures look pretty close to average in the south.

I keep saying - I've always rated NAVGEM highly

You are correct about the weekend low - still loads of variations and even the GFS own ENS have a large range of options for intensity and position. It really is causing havoc in model land.