The prediction phase consists in the elaboration of meteorological forecasts and in the evaluation of the effects on the ground that the predicted events could determine, both from a hydrogeological (e.g. landslides) and hydraulic (e.g. raising of the level of a river) point of view.
These assessments represent the event scenario, effects and damages that could affect life, property, settlements and environment, corresponding to criticality levels that each functional center communicates to the competent authorities for the different territorial levels.
The weather forecasts elaborated by the Central Functional Center are different from the general " weather forecasts" broadcasted through the media. They allow to focus only on situations that exceed certain thresholds of attention or alarm and therefore to be considered potentially harmful to people or things. Moreover, they allow to have more detailed information about incoming weather events, even in the uncertainty of the forecast, through the importance that a careful subjective analysis by forecasters provides to the data processed by numerical models.
Compared to classical weather forecasts, addressed to a generic audience - in which we use terms as "disturbed weather", "light rain", "heavy showers", "strong winds" - the information addressed to those who are responsible for assessing the impacts of the weather event and translate these elements into warnings and operational decisions, must reach the highest possible level of accuracy and detail with respect to the likely timing, location and quantification of the expected phenomena, compatibly with the uncertainty of the forecast.
Sometimes the meteorological picture, especially in the case of upcoming events, is particularly unpredictable and therefore susceptible to different interpretations. In order to avoid uncertainty during warnings, the State legislation has provided that every day, under the coordination of the Department, all institutional subjects, active in Italy in the field of operational weather forecasting, contribute to the elaboration of official weather forecasts to be transmitted to the National Service of Civil Protection. These subjects constitute the Technical Group for weather forecasts.
Technical group for meteorological forecasts
This group includes, in addition to the Central Functional Center, these centers of competence: the Meteorological Service of the Air Force and the Decentralized Functional Centers of the Regional Agency for Environmental Protection of Piedmont and Emilia Romagna, which have a recognized competence also on a national scale. When necessary, the Technical Group for weather forecasts also consults other Decentralized Functional Centers, extending the sharing of the forecast to the regions potentially affected by adverse weather events.
Forecasts and products
Every day, by 12.00 noon, this Technical Group produces a document of weather forecasts, valid for the day in which it is issued and for the following days. On the basis of this document, the Decentralized Functional Centers prepare the forecasts of interest for the Region and proceed to the evaluation of the effects on the ground.
In particular, in order to report the situations in which one or more meteorological parameters are expected to exceed certain thresholds of attention or alarm, the Department issues on a daily basis to the National Service of Civil Protection a National Weather Bulletin. It is a tool to connect information for all decentralized functional centers that indicates the weather phenomena relevant to civil protection expected for the day of issue and for the following day, the expected trend for the next day. The document is published every day at 3 p.m. on this website.
Each decentralized Functional Center (or the Central Functional Center for those not active) makes its own evaluations and represents them in bulletins; in case the expected weather events are particularly intense, it issues regional weather warnings. When these events affect two or more regions, the Central Functional Center, once acknowledged the assessments of the Decentralized Functional Centers, issues national weather warnings (warnings of adverse weather conditions) for the National Service of Civil Protection. The issuance of a warning is also announced through press releases, available on this website in the same section.
The forecast phase also consists in the evaluation of the effects on the ground that expected or ongoing events could determine, both from a hydrogeological (e.g. landslides) and hydraulic (e.g. rising river levels) perspective. On the basis of the forecasts developed by the weather sector and represented in the Bulletin of national weather vigilance and in the national and regional weather warnings, the hydro sector of the Central Functional Center evaluates the overall and probabilistically estimated criticality levels for each alert zone, agreeing this assessment with the Network of Functional Centers.
Forecasts and Products
These evaluations are collected in the National Hydrogeological and Hydraulic Criticality Bulletin, that the hydro sector of the Central Functional Centre issues every day, usually by 4.00 p.m. in order to connect the information among the Decentralized Functional Centres. They are also shared with the Ministries of the Interior, Agricultural Policies, Infrastructure and Transport and Environment, so that they in turn give information to their operational structures.
This document represents the assessment of the possible occurrence, or evolution, of ground effects (landslides and floods) related to weather events expected, or in progress, for the day of issue and the day after. The assessment is made on the basis of predefined event scenarios and is defined as the probability of occurrence of risk scenarios in an area not smaller than a few tens of square kilometers.
In particular cases, if the Decentralized Functional Centers make new criticality evaluations after the diffusion of the Bulletin of 16.00, the Central Functional Center issues a new Bulletin of national criticality in order to implement the related changes.
In case the meteorological events expected or in progress are expected to have a significant impact on the territory, and therefore a level of criticality that could be at least of moderate level, the Decentralized Functional Centers issue regional criticality warnings. For Regions where the Functional Centre is not active, the Central Functional Centre of the Department formulates these warnings.
On the basis of the criticality levels expressed in the Bulletins of hydrogeological and hydraulic criticality and highlighted in the regional criticality warnings, the Presidents of the Regions and Autonomous Provinces establish the different levels of alert for the territory. The different levels of alert correspond to different phases of activation that involve the implementation of emergency prevention and management actions, starting from the level that is closest to the territory: the Municipality. The Mayor is responsible for the activation of the Municipal Civil Protection Plan and for informing the population.
Monitoring and surveillance
In order to study the evolution of meteorological events and their impact on the territory, the monitoring and surveillance activity carried out by the Central Functional Centre is fundamental. The data collected by the observation instruments contribute to update the expected scenario.