Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 137: 483 – 502, January 2011 B The Central European limited-area ensemble forecasting system: ALADIN-LAEF Yong Wang, a * Martin Bellus, b Christoph Wittmann, a Martin Steinheimer, a Florian Weidle, a Alexander Kann, a Stjepan Ivatek- ˇ Sahdan, c Weihong Tian, d Xulin Ma, e Simona Tascu f and Eric Bazile g a Department of forecasting models, Central Institute for Meteorology and Geodynamics, Vienna, Austria b NWP division, Slovak Hydro-meteorological Institute, Bratislava, Slovakia c NWP section, Croatian Meteorological and Hydrological Service, Zagreb, Croatia d NMC, China Meteorological Administration, Beijing, China e Department of atmospheric science, Nanjing University of Information Science and Technology, Nanjing, China f NWP section, National Meteorological Administration of Romania, Bucharest, Romania g GMAP/CNRM, M´ et´ eo-France, Toulouse, France *Correspondence to: Y. Wang, Zentralanstalt f ¨ ur Meteorologie und Geodynamik, Hohe Warte 38, A-1190 Wien, Austria. E-mail: yong.wang@zamg.ac.at The Central European limited-area ensemble forecasting system ALADIN-LAEF (Aire Limit´ ee Adaptation Dynamique D´ eveloppement InterNational – Limited- Area Ensemble Forecasting) has been developed within the framework of ALADIN international cooperation and the Regional Cooperation for Limited-Area modelling in Central Europe (RC LACE). It was put into pre-operation in March 2007. The main feature of the pre-operational ALADIN-LAEF was the dynamical downscaling of the global ensemble forecast from the European Centre for Medium-range Weather Forecasts (ECMWF). In 2009, ALADIN-LAEF was upgraded with several methods for dealing with the forecast uncertainties to improve the forecast quality. These are: (1) the blending method, which combines the large-scale uncertainty generated by ECMWF singular vectors with the small-scale perturbations resolved by ALADIN breeding into atmospheric initial condition perturbations; (2) the multi-physics approach, wherein different physics schemes are used for different forecast members to account for model uncertainties; and (3) the non-cycling surface breeding technique, which generates surface initial condition perturbations. This article illustrates the technical details of the updated ALADIN-LAEF and investigates its performance. Detailed verification of the upgraded ALADIN-LAEF and a comparison with its first implementation (dynamical downscaling of ECMWF ensemble forecasts) are presented for a two-month period in summer 2007. The results show better performance and skill for the upgraded system due to the better representation of forecast uncertainties. Copyright c  2011 Royal Meteorological Society Key Words: ensemble prediction system; probabilistic forecasts Received 31 May 2010; Revised 25 November 2010; Accepted 26 November 2010; Published online in Wiley Online Library 11 February 2011 Citation: Wang Y, Bellus M, Wittmann C, Steinheimer M, Weidle F, Kann A, Ivatek- ˇ Sahdan S, Tian W, Ma X, Tascu S, Bazile E. 2011. The Central European limited-area ensemble forecasting system: ALADIN-LAEF. Q. J. R. Meteorol. Soc. 137: 483 – 502. DOI:10.1002/qj.751 1. Introduction Over recent years, limited-area model ensemble prediction systems (LAMEPSs) have become more important as scientific tools for improving the prediction of high-impact weather (especially mesoscale short-range probabilistic predictions), for identifying model error sources, and for developing methods for reducing weather forecast errors. Copyright c  2011 Royal Meteorological Society