Which phenomenon associated with thunderstorms can disrupt aircraft stability?

Strong updrafts and downdrafts are a key phenomenon associated with thunderstorms that can significantly disrupt aircraft stability. These vertical movements of air can create turbulent conditions within a storm. Updrafts can rapidly lift an aircraft upwards, leading to sudden changes in altitude and potential loss of control, while downdrafts can push the aircraft downward with a force that may exceed its capacity to respond effectively. This turbulence can occur with little warning, making it hazardous for pilots operating near or through thunderstorm areas.

In contrast, continuous cloud cover, high altitudes, and clear skies do not inherently pose the same level of risk to aircraft stability. While cloud cover can indicate the presence of weather systems, it is the strong updrafts and downdrafts within thunderstorms that directly affect the performance and handling of an aircraft. High altitudes alone do not contribute to turbulence unless linked to storm activity, and clear skies typically suggest stable flying conditions without significant weather disturbances.