Final answer:
An overshooting top is an indication of a thunderstorm with strong updrafts that push the cloud top into the stratosphere, signifying a very strong storm.
Step-by-step explanation:
An overshooting top indicates that a thunderstorm has very strong updrafts, which are powerful enough to push the cloud top into the stratosphere. This phenomenon is associated with particularly vigorous thunderstorm activity, where the convection process is intense. An overshooting top does not directly indicate lightning intensity, dissipation of the storm, or the certain presence of a tornado, although it is often associated with severe weather conditions.