Best Practices for Integrating High-Resolution Datasets to Message the Threat of Cloud-to-Ground Lightning in the Southeastern United States

During the summer of 2018, a subset of National Weather Service (NWS) forecasters from the Jacksonville, FL Weather Forecast Office investigated if the enhanced situational awareness gained by incorporating Geostationary Operational Environmental Satellite (GOES)-16 imagery with other high-resolution datasets could allow for the anticipatory communication of threats to NWS core partners. One of the outcomes from that applied study was the reality of messaging the threat of cloud-to-ground lightning strikes before they occur. Prior local research established precursor signatures from WSR-88D data to eventual cloud-to-ground lightning strikes. Combining these signatures from radar data with GOES-16 Day Cloud Phase Red-Green-Blue (RGB) imagery gave forecasters additional confidence to message a lightning threat. However, occasionally the precursors appeared coincidently with cloud-to-ground lightning and, in these cases, providing lead time was not possible. Other times, signals in the RGB and radar data implied lightning was imminent but did not occur due to the presence of failed updraft attempts before convective initiation. After a thorough investigation of these cases, effective practices were developed to assist with identifying which convective updrafts are associated with the highest chance of cloud-to-ground lightning and to mitigate identifying incorrect updrafts. This applied research and presentation has three primary objectives; first, explain why messaging the threat of cloud-to-ground lightning is an important component of on-demand decision support services in Florida. Second, illustrate how messaging is possible using GOES-16 and radar data. Third, using cases and lessons learned from the summer of 2018, present effective practices for identifying convective updrafts with the best chance for cloud-to-ground lightning. The presentation will conclude by hypothesizing a path forward for messaging the threat of lightning to core partners within the NWS Jacksonville, FL County Warning Area.