CHANGES IN THE ALADIN OPERATIONAL SUITE IN CROATIA IN THE PERIOD 2011-2015

National weather services issue weather forecasts based on the output from the numerical weather prediction models. Particular weather phenomena that have significant effect on safety can be characteristic of a certain country or region and may require specific model set-up in terms of model resolution and complexity to be forecast. However, the computational expenses of model set-up for operational purposes are limited by the available computer resources. In Meteorological and Hydrological Service (DHMZ) the operational numerical weather prediction uses ALADIN model. This paper describes the current NWP system and the changes introduced to the operational suite during the last few years. The operational suite in 8 km resolution and the dynamical downscaling of the wind field to 2 km resolution is run with higher frequency, the large scale model that provides the prognostic lateral boundary conditions has changed, operational forecast uses new model version with changes in model physics, dynamics and vertical discretization. Non-hydrostatic set-up of ALADIN has been running in 2 km resolution and 4 km resolution forecast using ALADIN model has been introduced. Here we show that improvements in the model physics that are beneficial for certain weather types, can deteriorate forecast quality otherwise. Although the increase in horizontal and vertical resolution improves the forecast, it partially restores the moist bias in the upper troposphere.