The El Nino background state is attempting to reinforce itself in the model output, hence the Azores High being displaced into Europe on a number of recent operational runs.
Unless tropical convection pulls out some new surprises, the theme of higher heights over Europe should gain ground over the coming few days. That's not to say they'll become stuck there like we had during the first half of November, but some periods of unusually high temps do look possible in between the polar maritime incursions. Following recent events, I'm not ruling out another unusual event or two though.
The current output has pretty much trended toward what the analogue years suggested we'd see in December this year, i.e. low pressure to our NW and high pressure Azores to Europe, while high pressure in the vicinity of Siberia is left relatively undisturbed. A good snow cover advance feedback is enhancing the Siberian High even further during the foreseeable future, which is promising for later in the season. So it all fits well with the theoretical side of things, but of course it's the theory that's behind the way in which the model handles certain situations, hence it can be considered most impressive if a model spots an unusual deviation a good way in advance.
The model trends of the past few days coupled with how things have panned out this month have reinforced my belief that our main hope for a significant cold, snowy spell of weather affecting locations beyond the usual benefactors lies with stratospheric wave breaking associated with that Siberian High, the hope being that this can achieve results by midwinter rather than mid-February as would be typical of a 'classic' El Nino winter. The hybrid nature of this year's events and its wobbles toward a more central ('Modoki') type event could prove helpful in this regard but a lot of this has little or no precedents to work with so... we're flying with (even) poorer vision than usual this season 
I know there are those who find it hard to place faith in stratospheric events and I can understand why; about half the time the resulting weather patterns end up shaped in the wrong way for the UK. Recent research has started to clarify the reason for this, though - it's to do with where the wave breaking takes place from. It turns out that wave breaking from the American side of the Pacific e.g. via an Alaskan Ridge tends to push polar vortex remnants toward Greenland, which is what happened last winter in late Jan/early Feb, diminishing and cutting short what would otherwise have been a decent cold spell for many of us.
Wave breaking from the Asian side, via a Siberian High, is another matter entirely, with high pressure over Greenland a favoured result.
Yet even then promises can't be made, as that high can end up too far west, the cold air plunging into the middle of the North Atlantic. So really, major strat. warming events are actually not that reliable at all - but when you have other background signals working against a cold pattern for the UK, they're among the most promising means of escaping the usual westerly regime. Such will be the case this winter... unless the El Nino goes full-on Central Pacific by the end of this year, which would be truly exceptional!
Originally Posted by: Stormchaser