Creation and use of storm-based probabilistic lightning hazard information and warnings
Kristin Calhoun, OU/CIMMS and NOAA/NSSL, Norman, OK
Tiffany Meyer, OU/CIMMS and NOAA/NSSL
Darrel Kingfield, OU/CIMMS and NOAA/NSSL
Holly Obermeier, OU/CIMMS and NOAA/NSSL
Chris Karstens, OU/CIMMS and NOAA/NSSL

Abstract
With roughly 20-25 million cloud-to-ground (CG) lightning flashes occurring across the US annually, CG lightning continues to be a significant hazard to lives and property.  While the NWS currently provides some information for decision support, a lightning specific product does not exist.  Continued research into the physical science of CG lightning combined with improvements in computing resources have led to the development of real-time forecasts of CG lightning probabilities.  This guidance provides the framework for the NWS to nowcast and communicate lightning hazard potential to the public.

As part of the Prototype Probabilistic Hazard Information experiment in the Hazardous Weather Testbed in 2016 and 2017, forecasters were asked to use a new MRMS CG lightning probability guidance to create rapidly updating probability grids and warnings for the threat of CG lightning for 0-60 minutes. This was the first time NWS forecasters were asked to provide CG lightning warnings and hazard information.  The output from forecasters was shared with end-users, including emergency managers and broadcast meteorologists, as part of an integrated warning team. 

Forecasters participating in the experiments were receptive to the probabilistic CG lightning algorithms and guidance and greatly anticipated the use within Decision Support Services and for general communication of public safety.  However, forecasters commonly noted a current lack of training and understanding in regards to various types of lightning data available and for forecasting CG lightning. 

Feedback from emergency managers consistently revealed a high desire for access to this lightning hazard information within their daily operations. In addition to confirming an end-user need, testing revealed that effective communication of lightning objects was sometimes lacking and communication of lightning information in this format could be difficult. Additional research is underway to incorporate relevant social and behavioral science methodologies to communicate lightning threats such that end-users can successfully assess and understand the information and take appropriate action.