Current status of SINFONY &#8211; The combination of nowcasting and numerical weather prediction for forecasting convective events at DWD
Authors: Blahak Ulrich ,   Team SINFONY
Published: July 2024

DWD's new Seamless Integrated Forecasting system (SINFONY) is currently targeted to improve very-short-range forecasting of intense convective events from observation time up to 12h ahead for Germany.There are different optimal forecast methods for different forecast lead times. The idea is to improve and combine them in an optimal way, including uncertainty information via ensembles.For this, seamless ensemble forecast products in observation space are produced, i.e., radar reflectivity composites, precipitation fields and convective cell objects, as well as informationson the probability &#160;of hazards like heavy precipitation, hail, wind gusts and lightning. These hopefully contribute to improve DWD's meteorological warnings (forecasters, automated systems) aswell as warnings of the German flood forecasting authorities.In the last seven years we developed in an interdisciplinary team&#160;1) radar Nowcasting ensembles for areal precipitation, reflectivity (STEPS-DWD) and convectivecell objects including hail and life cycle information (KONRAD3D-EPS) with good forecast quality up to 1-2 hours,2) a new regional NWP ICON-ensemble model (ICON-RUC-EPS) with assimilation of 3D radar volumes, cell objects, Meteosat VIS and IR channels and hourly newforecasts on the km-scale, whose quality exceeds Nowcasting after forecast hour 1-2,3) to get the best of both worlds for our customers, optimal probabilistic and ensemble combinations ("blending") of Nowcasting and NWP ensemble forecasts in observation space,which constitute the seamless forecasts of the SINFONY. Gridded combined precipitation and reflectivity ensembles are targeted towards hydrologic warnings.Combined Nowcasting- and NWP cell object ensembles help evolve DWD&#8217;s warning processfor convective hazards towards flexible &#8220;warn-on-objects.4) Common Nowcasting and NWP verification systems to help continuously improve the SINFONY components.For 2), efficient forward operators for radar volumes and visible/infrared satellite data enabledirect operational assimilation of these data in an LETKF framework. Advanced model physics (2-moment bulk microphysics with prognostic hail)contribute to an improved forecast of convective clouds.For 3), the ICON-RUC-EPS forecasts output simulated reflectivity volume scan ensembles of the German radarnetwork every 5&#8217;. Radar composites and KONRAD3D cell objects and their tracks are generated by the exact same methods as in the Nowcasting. These are seamlessly combined withthe STEPS-DWD- and KONRAD3D-EPS Nowcasts - resting upon the improvements for Nowcasting (1) and NWP (2).Meanwhile the system has matured and is in the process of operational installation. A number of its components have been run continuously duringthe last four convective seasons. This presentation will give a short overview on the systemstatus and its performance during the last years, as well as our future plans to enlarge lead time beyond 12h and to broaden the focus to other weather phenomena (renewables, air-traffic-related, winter), i.e., by integrating modern satellite data (MTG, IRS) into the system.