On December 2, 2013 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite flew over Indonesia and captured this true-color image of spectacular clouds rising over the landscape.
A series of towering clouds sit over Flores Island, at the top of the image, and obscures the lush green late spring landscape from view. Several clouds are tall enough that they cast shadows on the lower clouds below, especially on the northern edges of the rising clouds. A similar set of smaller, but also very tall clouds can be seen casting shadows on Sumba Island, to the southwest.
The Asian-Australian summer monsoon season begins in December and ends in March. The average rainfall in Maumere, Flores Island, in December is 141 mm (5.6 in), the third highest in the year after January (147 mm/5.8 in) and February (213 mm/8.4 in).
A monsoon is formally defined as a seasonal change in the direction of the prevailing, or strongest, winds of a region, but more often refers to the rains that accompany the wet monsoon. In the summer, the land stays warmer than the ocean, causing air to rise over the land and creating a breeze blowing from the ocean. This moist, rising air will form clouds as it reaches higher elevations. Sometimes – as seen in this image – the clouds formations can be quite impressive. And where such impressive clouds form, impressive rain generally follows.
Indonesia often experiences extreme precipitation during the wet monsoon season. The rains have been pouring down in Jakarta for the last several weeks. By December 7 flooding near Jakarta was widespread, with flood levels in Kampung Pulo were reported between 30 and 150 cm (12-59 in). Some flooded houses were located 15 m (49 ft) away from the river.