Interesting day often with three clear layers of clouds (ignoring the contrails): fluffy short-lived low cumulus, a mix of higher « flying saucer » or lenticular clouds, and a lot of high cloud. That last kept the sun from really blitzing through until mid afternoon but even mid morning it dried my washing pretty fast! The whole day is bracketed by an eeyrie blue dawn and, with a quick brush of lovely pink, a fade out to a similarly blue dusk. Around 3 minutes and 40 seconds in Mont Blanc develops a particularly good set of clouds, almost stationary but not quite, very slowly reshaping and disappearing to the right. A bit before that there’s something I’ve not seen before: many of the low, rapidly forming and disappearing cumulus puffs have a sort of beret of lenticular cloud above them. I usually associate lenticular clouds with some sort of « stationary wave system » downwind of the mountain peaks. Clearly that wasn’t explaining these ones. Just when I think I’m intuiting some of the physics I realise I haven’t a clue!!