Have you ever seen the rain? Observing a record convective rainfall with national and local monitoring networks and opportunistic sensors

Abstract. Short-duration extreme rainfall can cause severe impacts in built environments and flood mitigation measures require high-resolution rainfall data to be effective. It is a particular challenge to observe convective storms, which are expected to intensify with climate change. However, rainfall monitoring networks operated by national meteorological and hydrological services generally have limited ability to observe rainfall at sub-hourly and sub-kilometer scales. This paper investigates the capability of second- and third-party rainfall sensors to observe a highly localized convective storm that hit southwestern Sweden in August 2022. Specifically, we compared the observations from professional weather stations, C-band radar, X-band radar, Commercial Microwave Links and Personal Weather Stations to get a full impression of the sensors' strengths and weaknesses in the context of convective storms. The results suggest that second- and third-party networks can contribute important information on short-duration extreme rainfall to national weather services. The second-party network assisted in quantifying the magnitude and spatial variability of the event with high accuracy. The third-party network could contribute to the understanding of the duration and spatial distribution of the storm, but it underestimated the magnitude compared with the reference sensors.