This session focuses on advancing probabilistic hydro-meteorological forecasting from research to operations (and operations to research) across spatial scales and time horizons.

Building on the outcomes of the latest HEPEX workshop, this year’s session emphasizes the (co)creation of probabilistic hydrometeorological forecasting systems together with practitioners and stakeholders. In this session we will exchange and discuss how ensemble approaches are advanced to be scientifically robust while also being user-centric, impactful, and effectively communicating uncertainty to support decisions. Topics of interest include:

• Standardized evaluation frameworks for ensembles, including verification, benchmarking, and uncertainty quantification.
• Advanced computational science for scalable ensemble generation, data assimilation, and post-processing.
• Science communication to improve understanding of probabilistic forecasts and uncertainty.
• Impact analysis and inclusive forecasting, linking forecasts to diverse applications and sectors.
• Local implementation and policy science, embedding probabilistic forecasting in governance and practice.
• Behavioral science and crisis management, understanding how people act on forecasts, especially during extremes.
• Research-to-operations (R2O) and Operations-to-Research (O2R).

The session provides a platform for scientists, forecasters, and stakeholders to present advances, evaluate operational experiences, and explore pathways for delivering ensemble hydro-meteorological forecasts that create real value. Contributions from early-career professionals and interdisciplinary collaborations are especially encouraged.