The meteorological forcing data are all the information necessary to produce hydrological simulations.

• Historical hydro-meteorological time series records: they are used to calibrate the hydrological model, and to define the flood thresholds used to derive EFAS products. They are collected and managed by the JRC with contributions from MDCC, HDCC and COMP
• Real-time hydro-meteorological observations: they are necessary to define the starting points of the hydrological forecasts, also called initial conditions. They are collected from national agencies and quality checked by the EFAS Meteorological and Hydrological Data Collection Centres (MDCC and HDCC respectively) before being transferred to the EFAS Computation Centre (COMP).
• Meteorological forecasts: they are used to provide the future meteorological input to the hydrological models. Both deterministic (i.e single realisation from a single numerical weather prediction system) and ensemble (i.e. multiple realisations -also called ensemble members - from a single numerical weather prediction system) forecasts are used in EFAS, obtained from a range of providers.

The land surface data are all the information necessary to set-up and implement the hydrological models.

• Land surface data: they include land surface information and model parameters. They are prepared in advance by COMP, with contribution from the JRC.

Some of EFAS meteorological forcing and land surface data are provided as layers in the EFAS-IS mapviewer. An overview is provided in its dedicated page.