(Ac)
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Height of base: |
Between 2000 and
6000 m (6500 - 18000 ft) (mid-level clouds) |
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Description: |
Patches of
cloudlets, sheep clouds Clumps, rolls or lenses
with noticable shading and clear sky inbetween, 1º - 5º across (1
to 3 fingers at outstretched arm 30º above horizon) |
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|
Occurrence: |
World-wide |
|
|
Made of: |
Supercooled water
droplets, some ice crystals |
|
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Precipitation: |
None; may have virga
|
|
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Formation: |
Too
high fro thermals Warm
front (warm air sliding over colder air) |
|
|
Species: |
Stratiformis,
lenticularis, castellanus, floccus |
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Varieties: |
Opacus,
translucidus, perlucidus, undulatus, duplicatus, radiatus, lacunosus |
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How to
distinguish from … |
Cirrocumulus (Cc) |
Cc elements are
smaller than one finger Cc has no
noticeable shading |
|
Stratocumulus
(Sc) |
Cloud elements
are larger than 3 fingers width at 30º above horizon |
|
|
Cirrus (Ci) |
Ac can have fall streaks
resembling Ci, however Ci lacks the dense fluffy head |
|
|
Altocumulus Stratiformis undulatus (Morris, April 2006) |
Altocumulus radiatus (Morris, October 2006) |
Altocumulus (Morris, November 2006) |
|
Altocumulus lenticularis (Morris, September 2007) |
Same as left, 5 minutes later Altocumulus stratiformis opacus |
Altocumulus radiatus Morris, March 07 |
|
Altocumulus castellanus and
cirrostratus (Morris, May 07) |
Altocumulus Morris, August 06 |
Altocumulus floccus Morris, Jan 2008 |
|
Altocumulus lenticularis Morris, May16, 2008 |
Altocumulus with fall streaks (ice crystals) Morris, April 20,
2008 |
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Last
modified: 5/16/2008
Maintained
by Sylke Boyd