About 10AM yesterday, quite a lot of blue sky:

clouds1

2 minutes later, a bit less blue sky:

clouds2

2 minutes later again, not much blue sky at all:

clouds3

In the other direction about 5 minutes later, it’s all gone black (change of direction because I got my lens wet and a whole load of pictures were ruined):

clouds4

And in the original direction again about 1 minute later, heavy rain just starting: Walk home briskly!

clouds5

Cheers, Tom.