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

Abstract

<p>DWD's new Seamless INtegrated FOrecastiNg sYstem (SINFONY) is about to come to life in the next two years,<br>after 5 years of research and development.<br>For now, the system focuses on severe convective events in the very short time forecast range from minutes to 12~h.</p><p>There are different "optimal" forecast methods for different forecast lead times and different weather phenomena.<br>Focusing on precipitation and convective events up to some hours ahead, radar extrapolation techniques (Nowcasting)<br>show good skill up to about 2 h ahead (depending on the situation), while numerical weather prediction (NWP)<br>outperforms Nowcasting only at later hours. Ensembles of both Nowcasting and NWP help<br>to assess forecast uncertainties.<br>"Optimally" combining precipitation forecasts from Nowcasting and NWP<br>as function of lead time leads to the seamless forecasts of the SINFONY.</p><p>Different interdisciplinary teams work closely together in developing<br>a) radar Nowcasting ensembles for precipitation, reflectivity and convective cell objects,<br>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)<br>and hourly new rapid update cycle forecasts (SINFONY-RUC-EPS) on the km-scale,<br>c) optimal combinations of Nowcasting and NWP ensemble forecasts in observation space. 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<br>"warn-on-objects".<br>d) systems for common Nowcasting and NWP verification of precipitation, reflectivity and objects.<br>   In particular the cell object based verification will provide new insights into the representation of deep convective cells in the model. </p><p>For b), new innovative and efficient forward operators for radar volume scans and visible satellite data enable<br>direct operational assimilation of these data in an LETKF framework.<br>Advanced model physics (stochastic PBL scheme, 2-moment bulk cloud mircophysics) contribute to an improved forecast of convective clouds.</p><p>For c), the SINFONY-RUC-EPS outputs simulated reflectivity volume scan ensembles of the<br>entire German radar network every 5' online during its forecast runs.<br>Ensembles of composites and cell object tracks are generated<br>by the same compositing and cell detection- and tracking methods/software packages which are applied to the observations.</p><p>During the last year, all these methods have been further consolidated, and the RUC, along with some of the new nowcasting methods, has been run daily in a continuous test forecast mode.</p><p>This presentation will give a short overview on the activities of the last year and selected results of the test forecast mode.<br>Other presentations from SINFONY team members will give more details about the particular SINFONY components.</p>