Monday, 10 January 2005
A warning method for the risk of cloud-to-ground lightning based on total lightning and radar information
Many operational lightning warning systems rely either on a mix of data from cloud-to-ground (CG) lightning detection systems and electrostatic field measurements or on single-station lightning sensors that detect CG lightning and some cloud lightning over a limited range. Both types of systems can have problems determining when to end a warning at the end of a storm, particularly in the case of the stratiform rain regions of mesoscale convective systems (MCSs). Stratiform regions produce long, horizontal cloud flashes at a low rate that may be sustained for long periods of time. Some of these cloud flashes have CG components and others do not. Visual inspection of data from a three-dimensional total lightning mapping system, radar, and the U.S. National Lightning Detection Network have indicated that isolated CG flashes occur more frequently in certain portions of stratiform regions that have both relatively high reflectivity and repeated cloud flash activity overhead. The purpose of this paper is to introduce this simple observation as the basis for a warning strategy based on total lightning and radar data. We then provide a preliminary quantitative evaluation of the effectiveness of this strategy at Dallas-Fort Worth, Texas, where the combined data sets are available for a small number of MCSs.