JonStaples

That storm in France must be quite something. The 'total strikes in last two hours' counter on blitzortung's UK map reached 76,000 at one point - I've never seen it reach that level before, in fact I'm not sure I've seen that high a count on the 'whole world' map.

The storm I remember most is from quite a while back - 24th May 1989 (give or take a day, but I think that's correct). While I've seen a handful of storms of similar intensity (eg, early hours of 4 July 2015 was probably about the same), what I recall most about 24/5/89 was the total lack of build-up. The whole of May 89 was warm and sunny, and that day was the same. Not particularly humid, didn't have that "pre-storm" feel. At about 16:30 the sky was nice and blue, then on the southern horizon a flat, straight line of sheer darkness appeared and approached rapidly. I don't recall seeing the shape of a cum-nim cloud, just this completely flat zone of storm in complete contrast against the blue sky. The weather went from one extreme to the other just like that. I've not seen a storm approach in that way since then. The storm itself was a belter and it put an end to the warm spell.