Question

If cirrus clouds followed by cirrostratus and then altostratus is observed, which front is approaching?

Answer 1

As a warm front approaches, cirrus clouds tend to thicken into cirrostratus, which may, in turn, thicken and lower into altostratus, stratus, and even nimbostratus. Finally, cirrocumulus clouds are layered clouds permeated with small cumuliform lumpiness.