Ultra-Long Lightning Continuing Current

Particularly intense cloud-to-ground lightning discharges can exhibit continuing current of >= 500 ms duration. Evidence for this ultra-long lightning continuing current is reported from horizontal magnetic field recordings in the frequency range from 0.1-20 Hz at Hollister, California, 1-2 Mm away from the lightning flash location. These measurements are compared to the temporal evolution of lightning discharges monitored with the Lightning Mapping Array (LMA) during the Severe Thunderstorm Electrification and Precipitation Studies (STEPS) campaign and Video recordings from continuing current in distinct cloud-to-ground discharges. Lightning discharges with ultra-long continuing current may be associated with successive mesospheric transient optical emissions above mesoscale thunderclouds, denoted dancing sprites.