I watched large areas of clear skis, suddenly have large paths of
clouds on radar. Nothing I can remember from weather science
explains this. Where did they just suddenly appear from?
I've seen this a few time throughout the year. But have no idea
why it happens.
Large body of water, water condenses. Clouds form as they
eventually come over land as moisture forms into rain and storms.
Larger clouds aren't suppose to appear from almost nowhere, or at least
I didn't think they were suppose to.

Anyone have any ideas?

Fievel. (Everything I ever learned about whether is becoming garbage.)