Mature Stage

When the cumulus cloud becomes very large, the water molecules in it become large and heavy. They start to fall through the cloud when the rising air can no longer hold them up. Meanwhile, cool dry air starts to enter the cloud. This is known as entrainment. Because cool air is heavier than warm air, it starts to descend in the cloud (known as a downdraft). The downdraft pulls the heavy water molecules downward, making rain.

This cloud has become a cumulonimbus cloud because it has an updraft, a downdraft, and precipitation. Lightning and thunder start to occur, as well as heavy rain. The cumulonimbus is now a thunderstorm cell.

Next Formation Stage
Back to Thunderstorm Formation

Last modified prior to September, 2000 by the Windows Team

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