Hi,
my name is Vivi Mutia Yuheva, I'll tell you about the natural phenomena that Mammatus
cloud.
Mammatus,
also known as mammatocumulus (meaning "mammary cloud") is a
meteorological term applied to a cellular pattern of pouches hanging underneath
the base of a cloud. The name mammatus is derived from the Latin mamma (meaning
"udder" or "breast"). According to WMO International Cloud
Atlas mamma is a cloud supplementary feature.
Mammatus
are most often associated with the anvil cloud and also severe thunderstorms.
They often extend from the base of a cumulonimbus, but may also be found under
altocumulus, altostratus, stratocumulus, and cirrus clouds, as well as volcanic
ash clouds. In the United States, sky gazers may be most familiar with the very
distinct and more common cumulonimbus mammatus. When occurring in cumulonimbus,
mammatus are often indicative of a particularly strong storm or maybe even a
tornadic storm. Due to the intensely sheared environment in which mammatus
form, aviators are strongly cautioned to avoid cumulonimbus with mammatus. They
also attach to the bottom of other clouds.
Mammatus
may appear as smooth, ragged or lumpy lobes and may be opaque or translucent.
Because mammatus occur as a grouping of lobes.
The individual mammatus lobe average diameters
of 1–3 km and lengths on average of 0.5 km. A lobe can last an average of 10
minutes, but a whole cluster of mamma can range from 15 minutes to a few hours.
They usually are composed of ice, but also can be a mixture of ice and liquid
water or be composed of almost entirely liquid water.
True
to their ominous appearance, mammatus clouds are often harbingers of a coming
storm or other extreme weather system. While
they may appear foreboding they are merely the messengers - appearing around,
before or even after severe weather.
The
existence of many different types of mammatus clouds, each with distinct
properties and occurring in distinct environments.
One
environmental trend is shared by all of the formation mechanisms hypothesized
for mammatus clouds: sharp gradients in temperature, moisture and momentum
(wind shear) across the anvil cloud/sub-cloud air boundary, which strongly
influence interactions there in.
source:
http://en.wikipedia.org/wiki/Mammatus_cloud
