flippergirlpaints
I know there is an episode that Bob make rain coming down from clouds in a distance. I don't know the name, season and/or episode. From what I remember, he pulled down paint from the bottom of the clouds the same way we make reflections in the water. You can angle it or pulling it straight down. The effect was spectacular. Though, it doesn't look like light rain falling down but more like a heavy rain/thunderstorm type of rain.