"Graham Easterling" wrote
snip
Although the flow is easterly, didn't the air originate behind a
warm
front which went around the top of the high?

.... I haven't done a detailed trajectory back-track, but 'eyeballing'
the DWD archive, 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', i.e. with a slow-moving high cell there, the air could just
sit there and pick up the characteristics which (with modification
along the way) we're experiencing.

Martin.



--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023