From concept to reality: Implementing a new weather warning system at the German Meteorological Service

With the program RainBoW (Risk-based, Application-oriented and INdividualizaBle Provision of Optimized Warning Information), the German Meteorological Service (Deutscher Wetterdienst, DWD) is currently renewing the national weather warning system. RainBoW aims to increase the practical value of weather warnings for a wide range of users by improving their comprehensibility, extending their forecast horizon, and enabling individualization for specialized users with needs beyond those of the general public.

The new warning system will be deployed in stages, with the first release targeting warnings for the general public. Key changes include a standardization to three consistent warning levels across all weather warning elements, and a more temporally differentiated approach to thunderstorm warnings. The latter introduces a thunderstorm potential warning that bridges the gap between an uncertain pre-information and an acute warning triggered by already-observed convective activity. Finally, warning texts are restructured to increase their communicative effectiveness.

Translating the initial theoretical concepts into practice presents several challenges, as many design decisions do not have obvious solutions and require trade-offs. For example, it is necessary to balance precision and the usability of warning information by recipients – particularly when formulating the contents of warning texts, but also in specifying rules for proactively sending warning notifications in a way that avoids alert fatigue. Further challenges lie in the definition of rules for handling concurrently active weather warnings and keeping consistency with other (non-meteorological) national warning systems, which may use other warning level definitions.

This talk provides an overview of the ongoing developments within RainBoW and discusses selected implementation dilemmas encountered while moving from conceptual ideas into reality.