Cloud Watching

I am back from Peru to be greeted by very lovely weather indeed. This whole past week has been marvy here, but I notice today there are clouds creeping in. According to the "National Audubon Society Field Guide to North American Weather"(phew), altocumulus clouds may occur anywhere (Nooo, think of the children!). They accompany the more important moving weather systems. IF they only last a few hours or cover only a small portion of the sky, they don't seem to indicate a system moving in. They are just messin' around up there for fun (my words, not Audubon's). If, however, these clouds show up for an extended period of time, which these ones have, I've been seeing them for most of the day, then there will be "moisture".