Integrating Prediction of Precipitation and Hydrology for Early Actions (InPRHA): what is still needed to ensure effective delivery and use of probabilistic hydro-meteorological forecasts from minutes to days ahead?

Despite advancements in science and technology, predicting and preparing for floods remains challenging due to uncertainties in forecasting the atmospheric and hydrologic processes, limited real-time data, and forecast communication barriers. The Integrating Prediction of Precipitation and Hydrology for Early Actions (InPRHA) project is a five-year initiative within the World Meteorological Organization's (WMO) World Weather Research Programme (WWRP) that was initiated in 2024. It aims to enhance international research collaboration and scientific knowledge to improve flood hazard predictability and communication strategies for early warnings. The project integrates physical sciences, social sciences, and practitioner perspectives to advance hydro-meteorological forecasting and warning systems in a rapidly changing world.Here, we present and reflect on the key scientific questions across the seven themes that constitute the implementation plan of the project, which embraces the broader research and operational communities. We focus on the following activities that guide the project’s implementation plan: DEFINE (identifying challenges), CONSTRUCT (gathering case studies), EXPERIMENT (scientific evaluations), and ENGAGE (community collaboration). These activities should bring people with shared interests together to drive transdisciplinary research and enhance flood forecasting systems worldwide for improved early action and decision-making. They call the community to address research needs on flood multi-hazard interdependencies, local vulnerability assessment and response, and climate change impacts on precipitation and hydrological forecasts. International cooperation is key to collaborate on addressing the current challenges of re-envisioning the warning process.