Determining the mother-cloud

(Section 2.7.2.5)

Any determination of a mother-cloud, from which the cloud under observation originated, requires knowledge of the evolution of the clouds. Careful observation of the sky over time is necessary. The observer should use the relevant definitions and descriptions of clouds and on comparison with reference imagery. If there is any doubt of the origin of the observed clouds (“mutatus”), or of the manner of their formation (“genitus”), no “mutatus” or “genitus” indication should be used.