No ignoring the continued disagreement between GFS and UKMO regarding the extent to which the LP is organised next weekend.
GFS is a lot messier but delivers a good amount of precipitation that largely falls as snow, while UKMO looks better for a less stressful ride but perhaps rather lacking in precipitation away from windward coasts - but not necessarily.
Or perhaps we'll see a bit of both... a fairly extreme example on offer from GME this evening:
The LP is notably deeper by +84 hours than GFS has it (brings one heck of a cold blast from the west!) so a little hard to take seriously, but it shows how small features can develop in the cold, unstable flow (just look at all those kinks in the isobars!).
I've been thinking a bit more about the situation with the 850hPa temps seeming a bit on the high side for a northerly at this time of year. Among other things, the deeply unstable conditions seem a likely explanation; there's a lot more vertical mixing of the air, which means there's less of a temperature change between the surface and the 850 hPa level.
Combine this with the 850 level being closer to the ground thanks to low heights (drops a hint as to what low heights actually means), and the 850hPa temps are likely to be a fair bit closer to the 2m temps than you'd expect in a 'classic' northerly, which tends to see a a ridge building in quite fast, reducing the instability.
Originally Posted by: Stormchaser