As we started for home this evening, even though it was sunny, a battleship-grey cloud moved in overhead and we could see that at its edges tatters were hanging down as from a ragged skirt. That meant it was raining there and we were heading in that very direction! As we reached London Bridge it started to rain. We changed buses there and saw that there was a rainbow over the Thames.
It looks like a stormy enough scene and yet it was quite localized. When I turned from the above scene and pointed my camera in the opposite direction, this is what I saw.
The sky there was completely clear except for some harmless-looking white clouds on the horizon. You could be excused for thinking the photos were taken on different days, not merely 18 seconds apart.