Emergency Manager Preferences for Rapidly Updating Severe Weather Warnings

Abstract Threats-in-motion (TIM) is a technological innovation that would allow NWS forecasters to expand severe thunderstorm and tornado warnings in area and/or time, instead of issuing a series of new warnings. TIM allows warnings to “move” with the storm and provide more equitable lead time for locations downstream of the initial warning. While conceptual research demonstrates this value for example cases, research in NOAA’s Hazardous Weather Testbed revealed that motion instabilities (uncertainties in storm speed or direction, time intervals between forecaster intervention, and combinations of each) could also arise with this system that potentially limit usefulness or effectiveness of the product. To understand the potential trade-offs between the current and future systems, it is important to understand how core partners, such as emergency managers (EMs), would use TIM. In this study, 21 EMs from across the country participated in a simulated severe weather activity where they examined multiple TIM scenarios and provided feedback through surveys and focus groups. The TIM scenarios included visualizations of how TIM might behave under different situations: changes in storm speed, direction, and combinations of each. The simulation revealed that although EMs were optimistic about TIM, they had concerns about warning dissemination and public response. Specifically, the EMs were concerned about how the moving warning polygon could put locations in and out of warnings multiple times over relatively short periods of time, causing confusion from public safety and alerting standpoints.