In this talk, I will review the capabilities of contemporary long-range lightning networks to remotely detect lightning activity and the promise that the resulting data stream holds for investigations of storm morphology, cloud microphysics, and data assimilation into NWP models over data sparse ocean regions.

The waveguide between the Earth's surface and the ionosphere allows Very-Low Frequency (VLF) emissions generated by lightning, called sferics, to propagate over very long distances, especially over the open ocean. Therefore, data streams from long-range lightning networks have application for planning trans-oceanic flights and nowcasting of convective and tropical storms. By virtue of the relationship between lightning and rainfall rates, these data also hold promise as input for Numerical Weather Prediction (NWP) models as a proxy for latent heat release in convection. The results of efforts to quantify these relationships will be reviewed, along with results from studies of strike location accuracy and the diurnal cycle of the detection efficiency. The results from two different approaches to assimilate the lightning rate data into a regional NWP model will be presented, along with a discussion of the advantages and disadvantages of each approach.

A recently constructed Pacific Lightning Detection Network (PacNet) monitors lightning activity over the North Pacific Ocean with a widely spaced network of four ground-based lightning detectors. Current plans are to expand PacNet, with an additional 8 sensors to be installed in 2008 at island locations chosen to provide good detection efficiency across the western Pacific warm pool. As a result of these continuing efforts, PacNet is one of the few observing systems, outside of geostationary satellites, that provide continuous real-time data concerning convective storms throughout a synoptic-scale area over the open ocean.