| High Level Clouds |
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Cirrus (Ci)
- Cirrus are high clouds which are composed of ice cystrals that originate from the freezing of supercooled water droplets.
- They are thin and have a wispy appearance, and are often transparent.
- Usually indicates a change in weather will occur within 24 hours.
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Cirrocumulus (Cc)
- Cirrostratus are high clouds, composed of ice crystals.
- Appear as small individual cloudlets in rows. No shading can be seen on the lower surface.
- Usually indicate fair weather for the near future.
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Cirrostratus (Cs)
- Cirrostratus are high clouds, composed of Ice Crystals.
- Thin and uniform appearance, Often covering the whole sky. A halo of the sun or moon can usually be seen through the cloud.
- Usually indicate rain or snow within the next 12 - 24 hours.
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| Mid Level Clouds |
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Altocumulus (Ac)
- Altocumulus are Mid level clouds composed of water droplets.
- Similar to Cirrocumulus, but have larger individual cloudlets, and shading can be seen.
- If seen in the morning, prepare for a thunderstorm in the afternoon.
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Altostratus (As)
- Altostratus clouds are mid level clouds composed of ice crystals and water droplets.
- Generally uniform and grey in appearance, and frequently cover the entire sky. The sun or moon may also be seen through them, but is usually quite fuzzy.
- Tend to indicate a storm some time in the very near future.
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| Low Level Clouds |
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Stratocumulus (Sc)
- Stratocumulus clouds are low level clouds composed of water droplets
- Appear as low patches or sheets of grey to white cloud, with individual rolls or rounded masses.
- Do not usually bring precipitation.
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Stratus (St)
- Stratus clouds are low level clouds composed of water droplets.
- Appear as a uniform greyish layer and often cover the entire sky. They can sometimes cover hill tops.
- Often bring drizzle or light snow.
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Nimbostratus (Ns)
- Nimbostratus clouds are low level clouds that might consist entirely of cloud droplets or raindrops, or of ice crystals and snowflakes.
- They are thick grey clouds with a ragged base. Sometimes they cover the entire sky.
- Indicate rain in the very near future.
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Cumulus (Cu)
- Cumulus clouds are low level clouds, composed of water droplets.
- They are have a puffy appearence, a flat base and are white or light grey.
- Indicate fair weather unless they grow vertically.
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| Vertically Developed Clouds |
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Cumulonimbus (Cb)
- Cumulonimbus clouds are Vertically Developed Clouds which are composed of water droplets and ice crystals.
- Appear dark and very tall often extending through all the levels of altitude, and can be several miles wide. They often appear in a shape similar to a mushroom.
- Usually indicate a storm in the near future. Rain, hail, thunder, lightning.
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| Other Clouds |
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Contrails
- Contrails are visible trails of condensed water vapour made by the exhaust of aircraft engines.
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