The cerulean sky was dotted with fluffy white pompons of cumulous clouds.

I liked the cumulous clouds better; they looked like clouds were supposed to look.

They could see the sheet lightning glimmer on the bank of cumulous clouds behind the Holy Cross.

You should be worried about rising cumulous clouds, which are puffy and simultaneously hard-edged, like the bicep of a bodybuilder.

The sky was still overcast by low-hanging cumulous clouds that threatened to drop to the earth itself should they swell further.

Be ready for those puffy cumulous clouds or wavy lenticular clouds, the sun and moon, or, as seen here, the occasional flock of birds overhead.