Why does it rain in a large area at once? Can there be a dry spot in the middle of surrounding rain?

Question

How do clouds know when to rain all at once? How do they all get full at the same time and rain all at once? What happens when one is not full enough? Would there just be a dry spot encompassed by rain?

In: 4

Answer 1

It only rains when the air can no longer suspend the water in a cloud. This normally occurs with a temperature change.