COSMO-SREPS (csreps) is a high-resolution ensemble system for the short-range (up to three days). The system consists of 16 integrations of the non-hydrostatic limited-area model COSMO. The model is run at about 10 km of horizontal resolution, with 40 levels in the vertical. The ensemble is generated by taking into account different sources of forecast errors, in order to describe the uncertainty affecting the scales of interest in the high-resolution weather forecast at the considered time range. Initial and boundary conditions perturbations are provided by some members of the Multi-Analysis Multi-Boundary SREPS system of INM: the 10-km COSMO runs of COSMO-SREPS are driven by the four lower resolution (25 km) COSMO runs provided by INM, nested on four different global models (IFS, GME, NCEP, UM) which use independent analyses. Each of the four 25-km COSMO run provides initial and boundary conditions (3-hourly) to four 10-km COSMO runs, which are differentiated by applying different model perturbations. Four parameters of the schemes used for the parameterisation of the sub-grid processes are randomly changed, within their range of variability, in the ensemble members. Grid description: DDOM: xfirst: -6.02 yfirst: -7.0 xsize: 135.0 ysize: 83.0 xinc: 0.09 yinc: 0.09 xnpole: 190.0 ynpole: 40.0

cleps stands for COSMO-LEPS, the Limited-area Ensemble Prediction System implemented and developed by ARPA-SIM in the framework of COSMO consortium. This system is made up of 16 integrations with the non-hydrostatic limited-area model COSMO (formerly known as Lokal Modell). The 16 integrations takes initial and boundary conditions from 16 selected members of ECMWF EPS; the following prodedure is used to select EPS members: 1) Two successive runs of ECMWF EPS (starting at 00 and 12UTC) are considered; since each EPS set is composed of 51 integrations, 102 members are 2) a clustering algorithm is applied to construct 16 clusters (of different population); the clustering variables are Z,U,V,Q at 500, 700, 850 hPa at +96, +120 fcst steps; the clustering domain is 30-60N, 10W-30E. 3) within each cluster a representative member (RM) is selected on the basis of the same variables used for the clustering; 4) 16 RMs are selected; 5) each RM provides both initial and boundary conditions to the limited-area integrations with the COSMO model, which is run 16 times; 6) the limited-area runs constitute COSMO-LEPS Each limited-area runs has the following features: start once a day at 12UTC; hor. res. 10 km; vert. res. 40 ML; fcst length: 132h; post-proc frequency: 3h The integration domain cover the whole Central and Southern Europe, although, for D-PHASE, only a subdomain is delivered. Grid description: DDOM: xfirst: -6.02 yfirst: -7.0 xsize: 135.0 ysize: 83.0 xinc: 0.09 yinc: 0.09 xnpole: 190.0 ynpole: 40.0

cleps stands for COSMO-LEPS, the Limited-area Ensemble Prediction System implemented and developed by ARPA-SIM in the framework of COSMO consortium. This system is made up of 16 integrations with the non-hydrostatic limited-area model COSMO (formerly known as Lokal Modell). The 16 integrations takes initial and boundary conditions from 16 selected members of ECMWF EPS; the following prodedure is used to select EPS members: 1) Two successive runs of ECMWF EPS (starting at 00 and 12UTC) are considered; since each EPS set is composed of 51 integrations, 102 members are 2) a clustering algorithm is applied to construct 16 clusters (of different population); the clustering variables are Z,U,V,Q at 500, 700, 850 hPa at +96, +120 fcst steps; the clustering domain is 30-60N, 10W-30E. 3) within each cluster a representative member (RM) is selected on the basis of the same variables used for the clustering; 4) 16 RMs are selected; 5) each RM provides both initial and boundary conditions to the limited-area integrations with the COSMO model, which is run 16 times; 6) the limited-area runs constitute COSMO-LEPS Each limited-area runs has the following features: start once a day at 12UTC; hor. res. 10 km; vert. res. 40 ML; fcst length: 132h; post-proc frequency: 3h The integration domain cover the whole Central and Southern Europe, although, for D-PHASE, only a subdomain is delivered. Grid description: DDOM: xfirst: -6.02 yfirst: -7.0 xsize: 135.0 ysize: 83.0 xinc: 0.09 yinc: 0.09 xnpole: 190.0 ynpole: 40.0

COSMO-SREPS (csreps) is a high-resolution ensemble system for the short-range (up to three days). The system consists of 16 integrations of the non-hydrostatic limited-area model COSMO. The model is run at about 10 km of horizontal resolution, with 40 levels in the vertical. The ensemble is generated by taking into account different sources of forecast errors, in order to describe the uncertainty affecting the scales of interest in the high-resolution weather forecast at the considered time range. Initial and boundary conditions perturbations are provided by some members of the Multi-Analysis Multi-Boundary SREPS system of INM: the 10-km COSMO runs of COSMO-SREPS are driven by the four lower resolution (25 km) COSMO runs provided by INM, nested on four different global models (IFS, GME, NCEP, UM) which use independent analyses. Each of the four 25-km COSMO run provides initial and boundary conditions (3-hourly) to four 10-km COSMO runs, which are differentiated by applying different model perturbations. Four parameters of the schemes used for the parameterisation of the sub-grid processes are randomly changed, within their range of variability, in the ensemble members. Grid description: DDOM: xfirst: -6.02 yfirst: -7.0 xsize: 135.0 ysize: 83.0 xinc: 0.09 yinc: 0.09 xnpole: 190.0 ynpole: 40.0