Altocumulus Castellanus

altocumulus-castellanCloud of the Day – Altocumulus Castellanus

Altocumulus castellanus is a middle etage cloud similar to the lower etage cumulus species. It’s like ordinary altocumulus, but with significant vertical development. It’s as if a towering cumulus grew upward from a base of altocumulus. The name suggests the castle-like shape which, when a row of them develops, appears somewhat like a crenellated parapet on the castle wall.

altocumulus-castellanusaltocumulus-castellanus-cottonThe large vertical development of altocumulus castellanus indicates instability in the mid-level of the lower atmosphere. As such, they can be an indicator of some heavy weather in the offing, especially if seen early on a sunny day. As the Sun produces convection currents rising from the ground, these can multiply the effect of the instability above. This can lead to afternoon showers, even thunderstorms.

altocumulus-castellaltocumulus-castellaAltocumulus castellanus doesn’t produce precipitation by itself, but can be a harbinger of weather to come.

Apropos of nothing, here’s a link to a moving video on the “If This Be Treason” blog. It’s only about three minutes long. It’s from Thailand, so turn down the volume and read the subtitles.

Moving Three Minute Short From Thailand


3 comments for “Altocumulus Castellanus

  1. September 26, 2013 at 09:47

    Yes, a very moving video. I think these deeds of kindness do happen often. Perhaps not in the $$$ of the medical but on some level that makes a huge difference to someone. If only the media would report them instead of the gloom they do now.

    We are looking for the Rain Cloud of the day here. Get on your motor scooter and round some up. Please!!

    • September 26, 2013 at 10:10

      Don’t you know? If you hop in a circle on one foot while chanting “oogey boogey” it will rain. Eventually.


  2. December 2, 2013 at 06:45

    Watched the video again. Forgot I had already watched. Still very moving.

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