© Edward Engelbrecht
Waterkloof Ridge Bus Stop, Aquila Ave, Pretoria, 0181, South Africa
Latitude: 25° 48' 39'' S
Longitude: 28° 14' 45'' E
17 March 2016 0800 (Local Time)
Camera direction: towards E
Image P/S code: P.6.4
Image I.D.: 5732
CL = 7, CM = 2, CH = /
This is an excellent example of Nimbostratus where the appearance is rendered diffuse by continuously falling rain. Slight to moderate rain (25 mm) fell over the six hours leading up to this photo and a further 29 mm fell in the next nine hours.
No base can be discerned due to the rain and an overcast layer of pannus at an estimated height of 60 m (200 ft). The Nimbostratus appears to be illuminated from the inside and a reasonable amount of diffuse light is reaching the surface. This indicates the absence of small cloud droplets in lower parts of the cloud, permitting light to penetrate through a greater depth of the cloud. This is a common feature of Nimbostratus when rain sets in.
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A surface trough extends southward and to the east over the interior of the country. An upper-level (300 hPa) high pressure cell is over northern parts of South Africa. Moist air is being advected over the country due to the anticyclonic rotation of a ridging surface high pressure cell along the east coast of the country. The resulting wind direction at the time photo was taken was north-north-east.
High moisture content from surface to tropopause, saturated from 500 to 380 hPa
EUMETSAT channel 9 infrared image