Determining relationships between lightning and radar in severe and non-severe storms

Although many studies have described relationships between lightning and storm severity, much remains to be learned about these complex relationships before lightning data can be used effectively in operational forecasting. The combination of total lightning and radar-derived parameters can provide important new insights into the lightning distributions and storm-scale processes that indicate whether a severe storm is imminent. This paper examines data from the Lightning Mapping Array (LMA) network in Washington, DC, and WSR-88Ds in Sterling, VA and Dover, DE, using the Warning Decision Support System – Integrated Information (WDSS-II) software. Specifically, WDSS-II contains an algorithm that identifies and tracks storm features and extracts information from additional gridded fields (e.g., lightning and radar parameters). This paper briefly describes the automated WDSS-II procedures that are being used to data mine a large number of storms and transition from the more traditional case study mode towards the development of robust storm-scale relationships between lightning, radar, and storm severity. Although intense cloud-to-ground (CG) flash rates and intra-cloud lightning jumps have been shown to indicate strong storms, their relationship to specific types of severe weather remains unclear. Statistical methods are applied to quantify relationships between total lightning and radar parameters in order to diagnose, evaluate, and nowcast storm severity. Although these analyses are limited by the location and spatial coverage of the LMA network, the derived relationships are being developed so that they may be applied outside of these networks, using more readily available CG lightning and radar data. Looking forward, the upcoming GOES-R Geostationary Lightning Mapper (GLM) will complement the National Lightning Detection Network (NLDN) to provide total lightning data to all NWS offices for the first time. Therefore, the determination and application of relationships between total lightning, radar, and storm severity will support a smooth transition to GLM operations.