Is there a name for the formation of clouds that I can see about 15Km
off-shore above the sea. I live on the East coeast of South Africa.
These clouds are nearly always there. THe clouds are cumulo-nimbus in
appearance. I HAVE BEEN WONDERING IF THERE A SPECIAL NAME FOR THEM
LIKE THE ...... EFFECT?

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Request for Question Clarification by seizer-ga on 19 Apr 2003 02:02 PDT

Do these clouds begin at sea level, or do they begin somewhat above the sea?

Thanks,

--seizer-ga

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Clarification of Question by patlix-ga on 19 Apr 2003 06:34 PDT

These clouds begin somewhat above sea level.

Patlix --

You’re almost certainly seeing the effect of the Agulhas Current,
which runs southwest from Madagascar along the South African coast. 
It’s a warm, moist current being carried towards the cooler waters
towards Capetown (including currents arriving from Antartica).  The
Agulhas Current is very similar to the Gulf Stream, which arises in
the Caribbean and continues to influence weather in Great Britain.

You’re not seeing the clouds directly overhead because of the heating
of land, which is creating a barrier of rising air to keep the
moisture offshore.

A number of articles in the South African Journal of Science discuss
the cloud formation and the upper air currents which prevent the
cumulus from developing into thunderstorms:
South African Journal of Science
"Cumulus Cloud Formation Above the Agulhas Current" (July 1998)
http://www.nrf.ac.za/sajs/abjul98f.stm

"Observations of cloud formation above Agulhas Current intrusions in
the Southeast Atlantic" (November/December 2000)
http://www.nrf.ac.za/sajs/abnov00f.stm

This is a bit more complex but well-illustrated article on the Agulhas
current and what happens to cloud formations:
University of Capetown
"Observations of cloud formation above Agulhas Current intrusions in
the South-east Atlantic" (October 2000)
http://www.egs.uct.ac.za/~rouault/out/paper/sajsclouds/sajsclouds.htm


Google search strategy:
I initially started this search with "cloud formations" + shoreline,
thinking that you were seeing the impact of an onshore breeze (warm,
dry air from onshore picking up moisture progressively over many
kilometers – then condensing into a cloud layer).  My aviation weather
pages failed me in trying to show the effect clearly, so I switched to
the following search:
"South Africa" + shoreline + "cloud formation"

In the process I learned that you have a very special water current
that’s giving you the clouds offshore.  For the best images, let me
suggest the following Google search strategy:
"Agulhas Current" + clouds

One of the two Shuttle images brought up by that search shows the
denser clouds offshore to the east of your location:
"4076 Shuttle Images of the Indian Ocean"
http://rove.to/indian-ocean/

I’ll have to plan a visit now to see it for myself . . .

Best regards,

Omnivorous-GA