Abstract: A storm mapping system detects electrical activity caused by weather phenomena such as lightning strokes and the like and displays information related to the electrical activity as indicative of storm location with reference to an origin which is taken as the observer's location. A cathode ray tube (or other display means) provides a display and locations thereon are illuminated in response to the electrical activity. The azimuth of the display is indicative of the azimuth of the electrical activity. The distance from the reference location to any illuminated location is a function of the signal strength. Although signal strength is not a precise indicator of distance, it is a useful data item in that the more severe storms generate the maximum signal strengths. In contrast to the prior art systems, the storm mapping system of this invention illuminates a location whose distance from the origin is inversely related to signal strength.