Plate 25.
ALTO-CUMULUS INFORMIS.
Plate 25.
ALTO-CUMULUS INFORMIS.
A less definite form is shown in Plate [26]. It may also be regarded as only partly formed, but its construction is quite different, every part being misty and ill defined. It is a common cloud, especially in sultry summer weather with still air. Under those circumstances, after a hazy morning, it may be seen slowly forming during the afternoon, growing in density as the hours go by, until it reaches a maximum about five or six o’clock, after which it melts away, or settles down into small patches of high stratus. Most frequent in summer, it is by no means rare in autumn and winter, but still air is essential. From its hazy appearance it may be called alto-cumulus nebulosus.
