What is the recommended distance to maintain from a thunderstorm?

Maintaining a distance of 20 nautical miles from a thunderstorm is advised due to the severe turbulence and dangerous weather phenomena associated with these storms. Thunderstorms can produce strong updrafts and downdrafts, which can disrupt the stability of an aircraft and lead to significant hazards. By staying at least 20 nautical miles away, pilots reduce the risk of encountering severe turbulence, lightning strikes, and other hazards such as hail and microbursts. This distance provides a safety buffer that is crucial for maintaining control and ensuring the safety of the flight. Additionally, the turbulence and effects of a storm can extend well beyond its visible edges, making this distance a prudent standard for minimizing risk.