Have you ever been outside and it is raining and ever thought; has it just started, or do I put on my waterproof jacket or do I wait for it to stop?
Well, what about if I told you that the heavier drops fall last? This seemingly does not fit in with gravity as the larger and hence heavier drops should fall at the same speed as the lighter (smaller) droplets.
It is easily explained due to Newton's Second Law of Motion, F = ma. The rain is coming to you as the cloud is being pushed by the wind. The wind provides a constant force and this will cause the lighter drops to accelerate faster - hence they are pushed to the front of the advancing rain shower.
Want evidence - then climb a hill and look at the rain cloud from a distance. The rain underneath it is falling in a diagonal pattern facing the direction of the cloud.
So after the heavy drops have fallen the weather should clear up - that is if is not followed by a seconds cloud!