Applications of Lightning Data Outside the Contiguous United States

Scientists and forecasters have documented a wide range of operational applications for lightning data.  Lightning data have been shown to be useful for tracking convective cells beneath cold cloud shields, distinguishing thunderstorms from rain-only areas, identifying strengthening or weakening convection, monitoring convective storm mode and thunderstorm evolution, and supplementing radar data where coverage is poor.  Lightning emits very-low frequency (VLF) radio waves that propagate long distances (1000's of km) allowing ground-based long-range lightning detection networks to observe high-current cloud pulses and cloud-to-ground return strokes globally with fewer than 100 sensors.  However, non-uniformity of ground-based observations coupled with continual network modifications helped to motivate the planned GOES-R Geostationary Lightning Mapper (GLM).  Unlike the ground-based networks, the GLM will detect optical lightning signals from clouds, providing nearly uniform observations over land and ocean within 8x8 km grid cells (i.e., not point-based observations).  Preparations for the GOES-R GLM have revealed that lightning data are particularly useful in areas outside the contiguous United States.  This study documents important lightning applications demonstrated by forecasters at the National Weather Service (NWS) Ocean Prediction Center (OPC), Aviation Weather Center (AWC), and National Hurricane Center (NHC) using ground-based observations in preparation for the GLM.  These applications also provide insights into the potential fusion of the satellite- and ground-based lightning observations which will provide forecasters with additional lightning-based products and procedures.