Buttermilk Sky

Here in the US, most especially the Western part, I presume, this is known by some as a buttermilk sky. I am of a certain age to remember Roy Rogers and Dale Evans and her horse, Buttermilk. There was a western song, Ole Buttermilk Sky, and when the clouds look like cotton batting, or curds in buttermilk (I'll have to look that up to see if that's what it is referring to...one would suppose that's the origin, wouldn't one?) then you, too can say, "Oh, look a buttermilk sky."

PS
It is usually a precursor to rain, although this sky cleared in a matter of minutes and when I went back outside it was gone! Glad I saw it when I did.