block looks a bit weak on UKMO. Perhaps the 168 will show it sinking?

Looks OK to me.

GFS control also good, and the breakdown is potentially snowy with disrupting troughs

Will be interested to see the T168 , I'm not sure where it will head from T144. Mr Murr seems adamant it won't topple from there. 

The model output:

https://www.theweatheroutlook.com/charts/gfs/12_123_mslp850.png?cb=554

is so similar to 1981- just a day's difference. The 8.12.81 pattern shift was heralded by a surprising snowy dump in the SE. Richard Mabey in his book 'Cold Comforts' talked about the annual Varsity rugby match being played in 6 inches of snow. The days after had thundery snow & slack LP; this year it becomes an entrenched N'ly, breezy for sure.

What do we think of the 12h GEFS.?At 144h It seems to me as if there are are more ENS with the LP centre further north east

I think one needs to remember the old adage at times like this:

"Wait for cross model agreement at t96".  Im keeping my powder dry at present.

Thanks for the answers on snow row earlier.

Very decent midday runs.

Eyes down, look in for tonight’s ECM.

Never found that model much use, but DWD themselves are pretty up there. 

500hpa temps. Not often posted in here but they are very useful for convective potential. The colder the temperatures the more potential instability. And they are impressively cold. Fine details like wind shear, wind direction, fetch ultimately determine shower potential but the big picture is good.  

CAPE is also a good measure. Anything above 100J/Kg is good. Above 200J/Kg is enough for thundersnow. 

Rain turning to snow in the south and south east before it clears!? This would be interesting as temperatures start off at like +9 or +10c - Any chance this could be a thunder snow event!?

Agreed. Not always T+96 depending on the pattern; sometimes a little further out, sometimes closer. As for finer detail on precipitation probably not until well inside T+48, when other short-range models become useful.

ECM out to T+120 now and it doesn't develop the LP nearly as much and rattles it eastwards.

Don't get excited about backend stuff. Cold fronts struggled to produce meaningful snow even in 2010, I doubt they have a chance this year. Of course if the cold front stalls and becomes a warm front (as does happen sometime) that is a completely different story. Fast moving cold fronts are useless though.

Occluded fronts, however, can dump quite a bit though, particularly if they are active (intensity induced) and slow moving.