Roiling clouds

I love the word 'roiling' when applied to clouds.

This was one of the days we should have seen the super blue moon, but a thunder storm and lots of clouds put paid to that. A super moon occurs when the moon is closest to the earth in its elliptical orbit and so looks bigger and brighter. A blue moon occurs when there are two full moons in the same month. They are not blue, but they are quite rare, hence the term ‘blue moon’. A super blue moon happens when the two coincide. According to NASA the next one of those will be in 2037.