The image above shows a Cumulus-nimbus cloud that has an anvil top to it. The reason that can be identified is that the cirrus is in place above the center of the storm. The image below does not have an anvil top yet. The anvil top forms on CB clouds after they reach the height in the atmosphere where they begin to feel the upper level winds becoming too strong for them to continue development vertically. The storm on the right has not felt the upper level winds yet, that is why it lacks the anvil top. The winds get stronger higher in the atmosphere which gives us an indication that the storm on the left is higher in the atmosphere meaning that it’s probably got a better chance of being a severe t-storm unlike the one of the right. Both storms are capable of producing heavy rain.
Image Credits: RedOrbit.com Meteorologist Joshua Kelly