Bridging the gap between ensemble forecasting and end-user needs for decision-making on high-impact events

• Published in: Advances in science and research Vol. 22; pp. 39 - 52
• Main Authors: Ponzano, Matteo, Joly, Bruno, Beau, Isabelle, Renard, Elvis, Fifre, Gregory
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 29.07.2025; Copernicus Publications
• Subjects: Decision making; Energy industry; Ensemble forecasting; Forecasting; Heat stress; Heat tolerance; User needs; Weather; Weather forecasting; France
• ISSN: 1992-0636; 1992-0628; 1992-0636
• DOI: 10.5194/asr-22-39-2025

Ensemble forecasting is widely recognised as a more powerful and informative approach than deterministic forecasting, especially for anticipating high-impact events and supporting decisions under uncertain weather evolution. However, many end-users still struggle to interpret probabilistic forecasts and apply them in operational contexts. Misunderstandings, improper usage, miscommunication, and/or inappropriate design can lead to suboptimal or delayed decisions. In response, Météo-France has developed tools that aim to better adapt ensemble forecast information to the needs of different users. This article presents two prototype applications designed in collaboration with stakeholders. The first supports heat stress events management during the Paris 2024 Olympic and Paralympic Games, based on the WBGT (Wet Bulb Globe Temperature) index. The second focuses on late frost affecting vineyards during spring, with regard to mitigation measures and financial cost/loss optimisation. In both cases, ensemble forecasts were used to generate impact-oriented products to enhance operational decision-making procedures. The tools were evaluated through retrospective testing and end-user feedback. The results suggest that probabilistic forecasts are helpful when adapted to specific contexts. They can provide earlier and more confident decisions, even for users without meteorological expertise. These tools are not intended to replace expert assessment, but rather to clarify when action may be needed. Generalising such approaches could help extend the benefits of ensemble forecasting for sectors in which its potential remains underused.