Well it was actually raining here all day, too. I'd had enough so we drove out to Bowness on Solway to look across the estuary into Scotland. If you look at the picture above, the rain is slanting down below the cloud from right to left. All the time the cloud above was being blown from left to right. So why does the rain slant? I started by thinking that as soon as the drops leave the cloud they will experience horizontal air resistance (as well as vertical air resistance) and so be slowed down relative to the cloud. This might be true but there are problems.
1. Isn't the same wind that is pushing the cloud along also pushing on the rain drop? Surely the decrease in wind speed with height can't be that marked.
2. A could itself is surely just a collection of water droplets. It occurred to me to wonder what holds a moving cloud together to give the illusion that it is like a solid object. To what extent does a cloud itself experience air resistance? I've had a little poke around on the Internet but haven't yet found a convincing answer. More thinking to be done ...
