Automated Warnings: Ongoing developments of a prototype for wind gust, frost and rain

Providing early information about severe weather events is crucial for authorities and the public to take adequate measures. These measures will depend on the type and intensity of predicted severe weather and require different lead times to be put into action. Since current numerical weather prediction at the German Meteorological Service (Deutscher Wetterdienst, DWD) reaches forecast horizons of up to seven days, warning information can theoretically be provided at equally long lead times. This possibility is leveraged by a prototype for automated warnings that is being developed within the DWD RainBoW program ("Risk-based, Application-oriented and INdividualizaBle Provision of Optimized Warning Information"). In addition to the longer leadtimes, it has the bonus of retaining a high and consistent update frequency.

Prototypical warnings are produced in parallel processing chains for each warning element. At present the prototype can generate warnings for wind gust, frost and rain based on meteorological data from in-house numerical weather prediction and nowcasting systems. Each processing chain is triggered as soon as new input is available and transforms said input into probabilistic warnings plus additional meteorological information for context. This includes wind direction and possible worst case wind speeds for wind gust warnings; possible worst case temperatures for frost warnings; and expected accumulated precipitation and length of a rain event for rain warnings.

A processing chain consists of a series of modules for the individual production steps. Steps that are necessary for all meteorological warning elements have been generalized, so that the modules can be reused across all processing chains. If additional production steps are required, further modules can easily be added. The modular approach proved very valuable because it simplified building tailored processing chains, as well as extending them to new functionalities. Moreover, it allows for central controlling and monitoring of processes.

The research prototype is currently running continuously for the warning elements wind gust, frost and rain, for which it proved to be stable and robust. In this contribution, the prototype's setup and results for the three warning elements will be presented.