Mammatus Clouds Spotted
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:title: Mammatus Clouds Spotted
:date: 2017-09-15
:category: Blog
:tags: meteorology, clouds
:slug: mammatus-clouds-spotted
:related_posts:
:author: Chris Ramsay
:status: published
:language: en
:show_source: True

.. PELICAN_BEGIN_SUMMARY

I spotted some unusual clouds over the house the other day!

.. image:: https://farm5.staticflickr.com/4341/37050734616_94c8dc5e03_c.jpg
    :width: 800
    :height: 130
    :scale: 100
    :alt: Panorama shot of mammatus over the house

*Panorama shot of mammatus over the house*

I have always enjoyed identifying clouds and if I can take pictures of any
unusual formations. This type, `Mammamtus`_, is pretty rare in these parts; I
can count on one hand the number of times I have seen Mammatus clouds.

.. PELICAN_END_SUMMARY

According to the World Meteorological Organization's (WMO)
`International Cloud Atlas`_, Mammatus is not a type of cloud, but a
*supplementary feature*

.. image:: https://farm5.staticflickr.com/4360/37050735216_00a6bddb13_c.jpg
    :width: 800
    :height: 255
    :scale: 100
    :alt: Mammatus II

*Mammatus II*

The `Wikipedia article`_ states that "they often extend from the base of a
`cumulonimbus`_, but may also be found under `altocumulus`_, `altostratus`_,
`stratocumulus`_, and `cirrus`_ clouds".

.. image:: https://farm5.staticflickr.com/4403/36843129750_ff9532932b_c.jpg
    :width: 800
    :height: 452
    :scale: 100
    :alt: Mammatus III

*Mammatus III*

These clouds formations were seen around eight hours before a severe drop in
pressure brought the first `named storm of the season`_, Aileen.

.. image:: https://farm5.staticflickr.com/4379/36843129480_fdc1f37e2d_c.jpg
    :width: 800
    :height: 452
    :scale: 100
    :alt: Mammatus IV

*Mammatus IV*

Looking at my weather data, the cloud base was around 625 metres above sea
level and air pressure was falling steadily. There was almost no wind at ground
level and the freezing altitude was around 2,300 metres, that is the estimated
altitude at which the air temperature is at 0°.

.. image:: https://farm5.staticflickr.com/4374/37098248261_04a8c50191_c.jpg
    :width: 800
    :height: 452
    :scale: 100
    :alt: Mammatus V

*Mammatus V*

The reasons for this type of cloud formation occurring are ill understood. There
seem to be a few theories but nothing yet conclusive.

.. image:: https://farm5.staticflickr.com/4337/37050735906_1dbb140e3a_c.jpg
    :width: 800
    :height: 452
    :scale: 100
    :alt: Mammatus VI

*Mammatus VI*

Certainly not the most uniform of Mammatus formations ever; there are some
lovely examples out there that are far better than these. Nevertheless, the
formation was only visible for around 25 minutes, so I was quite pleased to
have looked out of the kitchen window just at the right time to have seen and
photographed them.

.. links
.. _`Mammamtus`: https://en.wikipedia.org/wiki/Mammatus_cloud
.. _`International Cloud Atlas`: https://cloudatlas.wmo.int/home.html
.. _`Wikipedia article`: https://en.wikipedia.org/wiki/Mammatus_cloud
.. _`cumulonimbus`: https://en.wikipedia.org/wiki/Cumulonimbus_cloud
.. _`altocumulus`: https://en.wikipedia.org/wiki/Altocumulus_cloud
.. _`altostratus`: https://en.wikipedia.org/wiki/Altostratus_cloud
.. _`stratocumulus`: https://en.wikipedia.org/wiki/Stratocumulus_cloud
.. _`cirrus`: https://en.wikipedia.org/wiki/Cirrus_cloud
.. _`named storm of the season`: https://www.metoffice.gov.uk/news/releases/2017/storm-names-for-2017-18-announced