Updrafts and downdrafts in large cumulonimbus clouds can recirculate water molecules within the cloud and contribute to the formation of

Hail. The answer is Hail. The water molecules are carried upwards in the updrafts, in which case they freeze while joining together with more water molecules, the water molecules then fall downwards, until being carried up again by another updraft. This process repeats until the hail that has been formed is heavy enough to escape the updrafts and finally reach the ground. I hope this answer helped!!!

Where's the picture of the model?