National Weather Service Initiative: Polygon Alerts for All Hazards

The National Weather Service (NWS) is working on a major change to the watches and warnings (henceforth alerts) that are issued by the agency. The need for improved capabilities has been identified and detailed, to include the ability by forecasters to produce alerts that match the geographic footprint of a given threat as it advances and evolves in severity over time. These alerts are also being assessed to update more frequently to keep pace as the threat area moves or evolves in such a way that more closely addresses known environmental changes for the hazard. The NWS currently applies such an approach to severe thunderstorm, tornado, flash flood, river, and snow squall warnings that are collectively referred to as polygon-based warnings. All other alerts are issued based upon geographical boundaries such as county and state borders, or pre-identified “zones” in collaboration with partner agencies. The NWS, in collaboration with the Office of Atmospheric Research (OAR)’s Global Systems Laboratory (GSL) and National Severe Storms Laboratory (NSSL), is working to develop a demonstration capability for standardizing the issuance of alerts at NWS Weather Forecast Offices utilizing a polygon-based approach for all types of hazards. Research-to-operations efforts aligning with and supporting this approach include a Forecasting a Continuum for Environmental Threats (FACETs) project known as “Threats-in-Motion (TIM).” Development of TIM has jointly been conducted by the NWS Meteorological Development Laboratory (MDL) and NSSL, with capabilities extended by GSL, which allows for hazards to have a rapidly updating polygon. Also, a multi-layered metadata approach is being assessed for a “community-centric warning” concept utilizing known societal information. This is in recognition of a need for service equity improvements in the effort to provide more actionable services to vulnerable populations. This presentation will provide an overview of the activities that have occurred and those that are underway. In preparation for the enhanced capabilities, service related projects (such as Hazard Simplification) are necessary, with other efforts under discussion to meet the current and future needs of society.