Detection and nowcast of severe thunderstorms over Slovenia

A method for detection and nowcast of severe thunderstorm events in the area of Slovenia is going to be presented.
 
Detection of intense convective cells is based on meteorological radar measurements and lightning discharges.
The pysteps module is used to search for closed areas above a certain threshold of radar reflectivity, and 
then it determines convective cells from the closed areas using several additional criteria related to the lightning activity.
A fine-tuning of detection is needed to provide optimal performance. This is achieved by first conducting a thorough analysis of the 
convective seasons from May to September (2020-2023) followed by an optimization approach which tries to provide the best configuration.
Primarily, the performance of detection is verified by the intervention data of the administration for civil protection and disaster relief (URSZR), where the events of hail, severe
winds and floods of stormwater were jointly analysed.
Due to the specifics of the interventions' database, the optimization and verification are performed only in the predefined 13 areas
where a sufficient density of reports are expected.
Each event detected is tracked back in time, which provides the ability to follow the lifetime of the specific thunderstorm event.
Detection generally performs well, and the verification results are comparable to the results of other studies performed in Slovenia or abroad.
 
Events detected at the target time are nowcasted in to the future.
This is currently performed by a nowcast of radar reflectivity field alone, followed by a repeated detection and tracking performed at the forecasted times.
The pysteps module is used to perform nowcast, since it already provides a list of well accepted methods.
 
The whole framework is currently used by operational subjective weather forecast process at the Slovenian NMS.
Also it is already used operationally to support automated warning system for a specific user.
Due to the modular approach, the framework has potential to be extended for various external costumer needs.