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L is
for....
Layer
Clouds
Clouds of no marked vertical development, known as "sheet clouds"
as opposed to "heap clouds". Cirrus, stratocumulus and
stratus are all examples of layer clouds. For more cloud descriptions
see "C is
for clouds."
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| Lenticular
clouds |
Lenticularis
A term applied mainly to certain types of altocumulus, stratocumulus
and cirrocumulus clouds which have the shape of lenses or almonds.
This type of cloud usually (but not always) appears in regions of
marked orography (e.g. near mountain ranges).
Lightning
A visible electric discharge associated with a thunderstorm. Various
types of lightning flash occur including "cloud discharge"
(within the thunder cloud), "air discharge" (between the
cloud and adjacent air) and "ground discharge" between
the cloud and the ground.
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| Lightning |
Studies
have shown that the ground discharge consists of at least two "strokes"
or "streamers". The "leader stroke" from cloud
to ground is relatively faint and takes a fraction of a second,
progressing in steps with many branches spreading out from it. This
is followed by an immediate "return stroke" from ground
to cloud which is extremely rapid and illuminates the main channel
and branches.
Low
A term commonly used to denote an area of low pressure. See also
"depression".
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