GLM Use, Feedback, and Development in the Hazardous Weather Testbed

Gridded products for the Geostationary Lightning Mapper (GLM) from both GOES 16 and 17 were examined by National Weather Service (NWS) forecasters and broadcast meteorologists over six weeks of the 2019 Hazardous Weather Testbed (HWT) and GOES-R Proving Ground Spring Experiment. From the end of April through early June, forecasters evaluated the GLM products in the context of live severe and hazardous weather issuing regional discussion, special weather statements, and warnings; forecasters provided feedback through surveys, live blogs, and lightning scientists. Overall, forecasters had a better understanding of the products in 2019 than in 2018. Average confidence in the products was much higher than in 2018 with forecasters ranking most products high or very high in terms of understanding. This was likely due to a longer period of exposure and limited access at some NWS offices. The top two products in terms of usefulness during severe weather operations were the Flash Extent Density (FED) and Minimum Flash Area products. Event Density and Flash Energy were also considered useful by the forecasters. Examples from both the HWT and associated research of these products in context of severe storms will be shown. These results and feedback from the forecasters are given to provide operational context for the use of GLM products and to target future research needs within the community.