Mike,
Do you have a definition for a buttermilk sky?
Mark Belshaw
Mark,
Great question!
A buttermilk sky is also know as a mackerel sky. Altocumulus and cirrocumulus clouds are mid-level clouds found between 8000-24,000 feet. They develop into clumps or heaps that resemble the scales of a mackerel.
Hope this helps.
My best,
Mike
