Lightning Mapping Arrays (LMAs) that image and monitor the total lightning activity in storms are being operated in northern Alabama, central Oklahoma and around Langmuir Laboratory in central New Mexico. The systems process and display the data in real time and are starting to be used in nowcasting of weather, particularly developing severe weather conditions. An additional system is currently being installed at White Sands Missile Range in New Mexico, also for nowcasting studies. In this talk we focus on the observational results obtained with the Oklahoma LMA and a similar network deployed during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) in northwestern Kansas and eastern Colorado during the summer of 2000. The lightning data valuably complement radar observations of convective storms by revealing the occurrence of strong convective surges and lightning ‘holes’ associated with strong updrafts and tornadic activity, the polarity of the lightning and storm electrification and, more generally, where strong convective activity is occurring.