C_L2 Cu of moderate/strong development

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Gallery
© R.K. Pilsbury	© R.K. Pilsbury
© C.S. Broomfield (Crown copyright)	© R.N. Hughes
© S.G. Cornford

These clouds are a development of C_L1. Their outline is usually clear cut, with horizontal bases and cauliflower shaped tops (top left photograph), although in fresh winds some raggedness may occur (top right). Sunlit parts are mostly brilliant white, while bases are relatively dark. The clouds are sometimes arranged in lines, called cloud streets, nearly parallel to the wind direction (middle left). They may also form with tall towers that may be tilted by the wind.

When well developed, these clouds may sometimes give showers (middle right) and in the tropics there may be abundant rain.

Small cumulus C_L1 and stratocumulus C_L5 may also be present, all having their bases at the same level. Well developed cumulus clouds may be accompanied by dense cirrus C_H2 or C_H3 and altocumulus formed by the spreading out of cumulus C_M6 (bottom left).

Over land, cumulus clouds usually disperse in the late afternoon or early evening. However over the oceans, maximum cumulus activity seems to occur in the late hours of the night. As there is little change in the temperature of the sea beneath them, the height of base of cumulus in the ocean trade wind belts is remarkably uniform at around 2,000 feet.

Classification
Description: Cumulus of moderate or strong vertical extent in the form of domes or towers.	Designation: CL=2 (C8)
	Latin name: Cumulus mediocris (Cu med) or Cumulus congestus (Cu con).

Related pages: Cloud classification | C_L guide | C_M guide | C_H guide | Cloud index