"Martin Rowley" wrote in message
news
the air that is associated with the warm front now quasi-stationary
across Britain was in the vicinity of the Azores 17th/18th - and that
location was behaving as a true 'air mass source'
Aha, yes - that'd explain it nicely. Looking at the current analysis chart
the UK is under a whacking great warm sector, which is just about perfectly
positioned in terms of high dewpoints for the UK.

It's not felt anything like a warm sector here (in Kent), of course, which
stayed on the cold side of the warm front. I guess I'm very lucky that the
warm front became quasi-stationary just up the road from here,
geographically speaking!