Nimbo, the little white cloud that turned black

This was a personification of the life cycle of a thunderstorm from beginning to end. The storm was given an exuberant spirit and dialogue as it metted out its lightning, thunder and rain on the earth below. It was a bit poignant at the end when the storm petered out of existense. I knew this book as a child in the 1960's; my elementary school had it in their library. I've been looking for years to acquire a copy; sadly, my old school no longer had a record of it when I contacted them in 2004. Still hoping I'll find it; it's a really charming childrens' book. - Jeffrey Hastings in New Jersey