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Wokingham, England, United Kingdom of Great Britain and Northern Ireland

Latitude: 51° 25' 5'' N

Longitude: 0° 51' 49'' W

27 April 2015 1021 (Local Time)
Camera direction: towards NW

Image P/S code: S.9.1

Image I.D.: 5000

C_L = 1, C_M = 0, C_H = 0

Formation of Cumulus humilis and fractus
This time-lapse video shows the initial formation of Cumulus fractus and Cumulus humilis clouds from a clear sky, in response to the heating of the ground by the Sun during the morning. The time lapse covers a period of 28 minutes.

A ridge of high pressure covered southern England, UK and the morning began with clear skies. The air temperature (at 1.3 m) overnight had fallen to 1 °C and the temperature over grass had fallen to –4 °C. In response to solar heating, the temperature over the grass surface had risen to above 20 °C by the time of the video in the mid-morning and the air temperature was 9 °C. The lowest level of the atmosphere was unstable to these temperatures and rising thermals began to form Cumulus clouds. In this initial stage of development, the clouds were of the species fractus and humilis.
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© George Anderson
Wokingham, England, United Kingdom of Great Britain and Northern Ireland
Latitude: 51° 25' 5'' N
Longitude: 0° 51' 49'' W
27 April 2015 1021 (Local Time)

Camera direction: towards NW
C_L = 1, C_M = 0, C_H = 0
Image P/S code: S.9.1
Image I.D.: 5000
Cumulus humilis
This photograph shows detached Cumulus clouds of small vertical extent. They are white with outlines that are generally not very ragged and have relatively clear-cut horizontal bases, such as at 1 and 2. Viewed from a distance, the clouds as a whole appear as if flattened or deflated, defining them as species humilis. Some may have rounded tops, as seen near the centre of the image, but without a cauliflower appearance. Cumulus humilis clouds never give precipitation. Towards the top of the image, the ragged and indistinct edges of the cloud identify the species as fractus, most likely in the process of developing into humilis.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
© Stephen Burt
St. Austell Bay, Cornwall, United Kingdom of Great Britain and Northern Ireland
Latitude: 50° 18' 45'' N
Longitude: 4° 46' 23'' W
11 August 2009 1341 (Local Time)

Camera direction: towards SE
C_L = 1, C_M = 0, C_H = 0
Image P/S code: P.9.1
Image I.D.: 2635

Formation of Cumulus humilis and fractus

Cumulus humilis