You are avoiding a thunderstorm that is in your flightpath. You are over 20 miles from the cell however, you are under the anvil of the cell. Is this a hazard?

Explanation

The Aviation Weather Handbook and PHAK Chapter 12 warn that pilots should anticipate hail with any thunderstorm, especially beneath the anvil of a large cumulonimbus, because hail can be carried out of the storm top and fall far from the core. Being 20 miles from the cell does not make flight under the anvil safe, and the hazard is hail, not being in a 'dissipation area'.