Well, perhaps not unusual in the run of things but unusual for the south east of the UK.
Last evening, following a prolonged period of extremely hot weather, cooler air rolled in from the west causing a temperature inversion - the developing cumulus, at the lower level, cast it’s shadow onto the upper levels and is something I had not seen for many years.
These two pictures of the event were taken about 15 minutes apart and shortly before the start of the best thunder storm, which lasted for most of the night, I think I have ever heard and witnessed.
Tweakie.