Object-based aviaton convection forecasts from global ensemble model

In the framework of a single european sky and to improve Air Traffic Flow and Capacity

Management, involved actors need to share a common situational awareness of the airspace

conditions. These include the meteorological conditions with a focus on weather phenomena with a

strong impact on air traffic and network operations such as convection.

Within this framework, Météo-France is working to provide a new product of convection forecasts

based on ensemble prediction system (EPS) and global model, and is developing a similarity-based

method (Rottner et al., 2019) at Centre National de la Recherche Météorologique (CNRM).

The method aims to detect areas where meteorological conditions are homogeneous which are

called called objects. The latter are defined by a reference histogram representing the

meteorological phenomena to be detected and so are physically consistent. The similarity-based

method can be applied to each member of a EPS. The results can be summarized by a map that

contains the information predicted by all members of the ensemble. Thus, it provides spatialization

for local weather events. This method is currently tested to detect rainfall objects, however we can

apply this method to detect other event type, like convection. To discriminate the convection

characteristic within these rainfall objects, we use a diagnostic of cloud top pressure extracted from

global model outputs. Furthermore, to improve the convection forecast accuracy, the similarity-

based method can also be applied to several models to create a composite of convection forecast.

Météo-France will soon deliver a convection potential product to aeronautical users.