Current status of SINFONY - the combination of Nowcasting and Numerical Weather Prediction on the convective scale at DWD

The development of DWD's new Seamless INtegrated FOrecastiNg sYstem (SINFONY) has matured and a number of components have been run  continuously in near-realtime on a daily basis during the last two convective seasons. This presentation will give a short overview on the system components itself and their current status, and will report on the results of this years convective season.

There are different "optimal" forecast methods for different forecast lead times and different weather phenomena.
Focusing on precipitation and convective events up to some hours ahead, we developed

• a) radar Nowcasting ensembles for areal precipitation, reflectivity and convective cell objects,
• b) a regional ICON-ensemble model with extensive data assimilation of high-resolution remote sensing data (3D radar volume scans of radial winds and reflectivity, cell objects, Meteosat VIS channels and lightning) and hourly new rapid update cycle forecasts (SINFONY-RUC-EPS) on the km-scale,
• c) optimal combinations 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's warning process for convective events towards a flexible "warn-on-objects",
• d) systems for common Nowcasting and NWP verification of precipitation, reflectivity and objects. In particular the cell object based verification will provide new insights into the representation of deep convective cells in the model.

For b), new innovative and efficient forward operators for radar volume scans and visible satellite data (SEVIRI-VIS) enable
direct operational assimilation of these data in an LETKF framework. In late summer 2022, we finally could also activate the SEVIRI-VIS data in the daily RUC. Advanced model physics (2-moment bulk cloud mircophysics) contribute to an improved forecast of convective clouds. A stochastic PBL scheme has been developed, but is not yet in daily use.

For c), the SINFONY-RUC-EPS outputs simulated reflectivity volume scan ensembles of the entire German radar network every 5' online during its forecast runs. Ensembles of composites and cell object tracks are generated by the same compositing and cell detection- and tracking methods/software packages which are applied to the observations.

Considerable improvements in the RUC compared to the 2021 season lead to the situation that RUC starts to outperform Nowcasting already after about 1 hour lead time, both for areal Nowcasting and cell object Nowcasting. Life-cycles of simulated convective cells proved to be surprisingly realistic, although some problems in details of cell organization and cell size remain and need to be looked at.

Other presentations from SINFONY team members will give more details about particular SINFONY components.