TOP-OF-THE CL0UD AND CLEAR AIRL IGHTNING
There are numerous reports of lightning propagating upward from the tops of clouds and perhaps to the ionosphere [46]-[52]. Lightning has also been reported when there is a clear blue sky [531-[58), commonly referred to as a “bolt from the blue.” Most of these reports, however, refer to a situation where there is blue sky overhead and the thunderstorm is 10 or more km away, out of viewing range, from where the lightning originates. However, there are photographs and supporting