Top
-
Cirrus
(often in bands) and
Cirrostratus
, or Cirrostratus alone
- progressively invading the sky
- generally growing denser as a whole
- continuous veil does not reach 45 degrees above the horizon
from the top downward:
photo by Kruegler
photo KNMI
photo KNMI
photo by R.K. Pilsbury (Crown copyright)