Lightning observations over the oceans provide valuable information for identifying regions of severe weather and the related threat of turbulence. Global Atmospherics, Inc. has provided real-time lightning observations over the oceans for use by the U.S. National Weather Service Aviation Weather Center since 1996. This paper discusses the features and limitations of this information, and summarizes recent experiments that quantify the performance of an integrated system composed of widely separated networks of sensors. The practicality of transoceanic lightning detection is also illustrated, using sensors located in the U.S. and France. Work to date has provided the basis for a multi-country real-time experiment to be carried out during the Spring/Summer of 1999.