
.topic 20
denotes the conditions which generally exist during precipitation and a short time before and after


.topic 30
Altostratus, the greater part of which is sufficiently dense to hide the sun or the moon, or Nimbostratus


.topic 40
Detached clouds, generally dense and with sharp outlines, developing verically in the form of rising mounds, domes or towers, of which the bulging upper part often resembles a cauliflower. The sunlit parts of these clouds are mostly brilliant white; their base is relatively dark and nearly horizontal. Sometimes Cumulus is ragged

.topic 50
Clouds in the form of irregular shreds, which have a clearly ragged appearance

.topic 60
Generally grey cloud layer with a fairly uniform base, which may give drizzle, ice prisms or snow grains. When the sun is visible through the cloud, its outline is clearly discernible. Stratus does not produce halo phenomena except, possibly, at very low temperatures. Sometimes Stratus appears in the form of ragged patches.


