Storm-based convective warning best practices

Since the advent of Storm-Based ("polygon") convective warnings, the National Weather Service (NWS) has continually evaluated ways to improve the service. Several recent NWS Service Assessments after major severe weather events, feedback from forecasters and NWS partners, and reviews of performance and verification have resulted in several recommendations for improvements. These have resulted in guidance for improving polygon creation, such as choosing the appropriate size of the polygon for various scenarios, dealing with multiple storms in the same area, anticipating possible changes in motion or deviant motion, and other warning challenges. Additionally, national policies were developed on "Tornado Emergencies" and tornado and severe thunderstorm path forecasts (or "pathcasts"). This presentation will discuss the service and performance evaluation, the recommendations developed, pathways to implementation, warning policy changes (such as "tornado emergency" and "pathcasts"), and ideas for possible future improvements.