Arpege 12z even further south. London in with a chance.
https://www.meteociel.com/modeles/arpege.php?ech=47&mode=42&map=300
So, after the 12z runs we have Arpege now predicting snow for the northern part of Herts and northwards, albeit after a damp start.
Alaro has firmed up on snow north of London, some of it quite heavy.
WRF has the rain-snow boundary north of Cambridge, but it’s moved south a little v the previous run.
ICON has the boundary slightly further north than WRF, with rain for Norfolk & Suffolk. That seems to be partly down to a lower intensity of precipitation, which as Q has mentioned is critical when there needs to be cooling of the air.
UKMO has the snow in a similar zone to ICON, but again I am pretty sure the boundary has trended south.
So, 36-48 hours to go and still a lot of uncertainty across the swathe of the country north of the Thames-Severn Estuary line (aka M4 corridor…).
My guess right now for here would be some white stuff coming down but mostly wet on the ground.
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E