The significance of the meteorological applications of lightning data is that in recent years we have acquired the technology to use the observations of lightning in many areas of operational meteorology. Consider the past for a moment. In the 1940's, we began to observe the characteristics of cloud systems with radar; in the 1960's, we observed them with satellites in the visible and infrared wavelengths; and in the 1970's and 1980's, we developed the techniques to monitor lightning activity from satellites and to detect the lightning to ground from cloud systems using ground based lightning detection networks. The combination of radar, satellite, and lightning observations of weather systems has opened a new area of applied meteorology that is attracting the interest of both the research and the operational meteorologist. Copyright 1987 by the American Geophysical Union.