Looks a bit rubbish for most though. It's going to be a case of hoping something turns up short notice snow wise.
Having had a nice bath, I'll put down a bit of what I wrote earlier (I spent a good 20 minutes writing that post, which was why I was miffed!)
Generally, it does look like we're in for something unusual in recent times, a notable northerly. All the conditions are there for some severe minima over Scotland: we have low 500hPa heights incoming, low 850s, the both together indicating a real Arctic airmass; there will be snow on the ground, light winds and a col overhead, so nothing much to prevent cold air pooling close to the surface. I wouldn't be at all surprised to see -15 or even -20 reached over the coming days. (Note that the rather excitable MetO GM has been showing much lower temperatures than have been recorded - it had -14C earlier this morning, when the coldest PWSs in the area, the Cairngorms, only had -8s).
The other notable thing is how far south that deep cold airmass will reach; yesterday's 18z GEFS was a high point, with a -10 mean down here. Unsurprisingly the 0z GEFS suite has backed off from that a bit, but it still hits -9 briefly. In tandem with that, we see low dewpoints modelled, another characteristic of an Arctic airmass. That should wick away water from the ground, enabling widespread (and literal) hard frost to develop. With the sun still weak, I've a feeling we're in for a magical few days, the sort where ponds remain frozen, frost lingers all day long. It also means if any snow appears it should avoid melting (as it did down here on Monday).
That brings me onto snow itself: we all know that given a deep cold airmass, convection is something to look out for - it doesn't take much to spark this. Others will know their areas better than I do, but there are bound to be lake-effect showers in areas exposed to coasts, as well as troughs or other features moving south - I would expect snow to pop up almost anywhere, but it'll be short notice - it always is! Just look at the snow we had down here on Monday, the modelling of it was unimpressive, even though it was likely to happen.
The midweek snow is now looking like mainly heading over France, perhaps clipping the south (as in the ECM, which is why I wrote I liked it). I'm not keen on the post 168 evolution, mind you! The MetO 168 is worth commenting on, as it's an incredibly rare sighting of cold WSW'lies... the legacy of the earlier cold lingering on for a bit. The MetO, incidentally, takes the snow hundreds of miles further south than the ECM, so we trade snow for deeper cold.
Towards the end of the week, yesterday's modelling was emphatic on a warmup, with T2Ms hitting 9C as a mean on the 21st down here. I expect that to be similar today, but it's also worth mentioning that both GEFS and EPS have a small number of members maintaining the cold throughout - and we can't really expect the charts to be terribly accurate 9 days out, after all. The models are excellent at handling zonal jets, but as can be seen at the moment they're having "fun" pinning down that split we're seeing! If it does warm up, though, at least there will have been a good 5 days or so of deep cold over the UK.
Obviously Scotland is the place to be this week - and I look forward to seeing reports in due course, including ones from our Scottish members on here!