Integrating KONRAD3D into the nowcasting guidance system NowCastMIX at DWD

Abstract

<p>Short-term warnings for severe thunderstorms are produced at the German Weather Service (DWD) with the support of NowCastMIX, which automatically creates warning areas for the next 60 minutes. In short, NowCastMIX processes meteorological fields from various sources such as NWP, radar, surface station reports and lightning detections. Based on the available data, the potentials for heavy rain, hail and severe gusts are calculated every 5 minutes by a hierarchy of fuzzy logic sets. From these potentials, categorical thunderstorm warnings are issued for detected cells. By condensing the information into clusters, regions are then identified which require warnings.<br />One system that NowCastMIX currently uses as input is KONRAD. KONRAD is a method for automatic detection, tracking, and prediction of thunderstorm cells based on two-dimensional weather radar data. In recent years, a new scheme, KONRAD3D, has been developed, which provides three-dimensional objects of detected cells with the help of 3D radar volume scans. KONRAD3D also provides new state-of-the-art approaches to capture features such as the storm track more smoothly and consistently over time.<br />In order to let NowCastMIX benefit from this new development, KONRAD will be replaced by KONRAD3D. Subsequently, reanalyses with the new KONRAD3D module will be calculated for 194 convective days over a period of three convective seasons. A comparison of both data sets will show in which areas NowCastMIX benefits from the three-dimensional objects provided by KONRAD3D. The fuzzy logic of NowCastMIX will be tuned based on the reanalyses in order to optimize the probability of detection and false alarm ratio for the administrative districts of Germany.</p>