A Decade of NWS Storm-Based Warnings for Convective Threats: Analysis of the Paradigm and Considerations for the Future

In late 2007, a new era began for the National Weather Service (NWS), with major operational changes in convective warning creation, dissemination, communication, and verification. Tornado, Severe Thunderstorm, Flash Flood, and convective marine warnings, once "county-based," would now follow a “storm-based” paradigm. As with their county-based predecessors, Storm-Based Warnings (SBW) alert the public to short-fused convective threats. However, the warned area in an SBW is limited to the bounds of the polygon, as determined by the warning forecaster. The goal of this change was to better define the area within a warning, thus reducing "false alarms" to towns and jurisdictions in the same general vicinity. This is a significant advantage to those responsible for disseminating the warning message and also provides economic benefits over time.

Effective communication of warning information has been, and still remains, the most important consideration with regard to the SBW program. Warning messaging has improved significantly in the new paradigm, with better graphical representations of geographic regions in and around warning areas. A historic tornado season, only a few short years after implementation, helped define new, clarified text for the warning products. Now, ten years after the nationwide implementation of SBWs, innovations in technology, improvements in numerical weather prediction, and a burgeoning emphasis on social and societal risks, impacts, and understanding are raising questions about the future of short-fused weather warnings. This research will analyze the improvements and deficiencies brought about by the operational shift to SBWs, and look forward to new possible future improvements, with particular focus on Tornado and Severe Thunderstorm Warnings.