The ItaliaMeteo Agency disseminates weather forecasts over the national territory, using the most modern numerical modeling systems of the atmosphere with high spatial resolution.

Weather forecasts differ in relation to the time scale, which varies from a few minutes and hours following the time of observation (nowcasting forecasts) to two to three days, and then to weekly, monthly, and seasonal scales.

The margin of error of meteorological models is greater in the case of smaller temporal and spatial extent of the phenomena to predict.
Therefore, one of the Agency’s activities is to reduce uncertainty and reduce errors typical of any forecasting process. To this end, ItaliaMeteo promotes the progressive overcoming of deterministic approach, to the purpose of the development of ensemble systems, which allow better management of uncertainty, providing a probabilistic perspective of weather forecasting.

Nowcasting forecasts require effective and comprehensive integration of data from ground stations and radar and satellite platforms to improve the estimation of the evolution of essential weather magnitudes and for real-time surveillance.

The use of nowcasting techniques, the use of Artificial Intelligence, and the assimilation of observed data into numerical weather modeling systems allow various actors in different sectors (transportation, energy production and distribution, civil protection) to deal as correctly as possible with intense, fast-moving events that require innovative and timely response systems.

Numerical Weather Prediction (NWP) modeling is the basic tool for making weather forecasts, and consists of a set of equations that simulate the evolution of the atmosphere, a data assimilation system to generate the initial condition from which the evolution is calculated, data or boundary conditions, in the case of integrations over a limited portion of the globe (limited area models), and an appropriate supercomputing system.

The resulting products must be visualized and in many cases post-processed to fit the needs of different users. Verification activities are also necessary to assess the quality of the forecast products.

Unlike deterministic modeling, which relies on a single numerical forecast model, ensemble systems involve the simultaneous use of several numerical models, obtained through parallel simulations that start from nearly identical initial conditions and can therefore offer different forecast scenarios.

The shift to probabilistic forecasting allows the reproduction of a probability of occurrence to provide useful elements for decision-making processes.