With climate change and variability posing challenges to sub-Saharan Africa’s development sectors, weather and climate information services are crucial for building climate-resilient development pathways (Hansen et al., 2022). Seasonal forecasts in particular provide prospective information about the upcoming season, with a particular focus on precipitation and temperature (Guido et al., 2020; Hansen et al., 2011). However, a direct and linear translation of the seasonal forecasts to sector-specific information such as water resources and agriculture can lead to inaccurate recommendations. Integrating seasonal forecast data into biophysical models can enable the generation of sector-relevant actionable information that can improve the decision-making (Hansen, 2005; Houngnibo et al 2023). This would contribute to a better understanding of the impacts of climate forecasts in the water and agriculture sectors, among others, thereby facilitating more informed decision-making. Regional operational meteorological centers, including AGRHYMET Regional Climate Center for West Africa and the Sahel (AGRHYMET CCR-AOS), are regularly producing seasonal climate forecasts to help inform adaptation decision-making at various levels. As a Regional Climate Center, AGRHYMET CCR-AOS coordinates the development of consensus seasonal forecasts through Regional Climate Outlook Forums (RCOF), which bring together experts from National Meteorological and Hydrological Services (NMHSs), basin organizations, and global climate centers. AGRHYMET CCR-AOS has proposed a new approach to translate seasonal forecasts into sector-specific actionable information for agriculture and water sectors through crop and hydrological models. This is referred to as extended seasonal forecasts in agriculture and water sectors (Houngnibo et al 2023). As part of AICCRA West Africa cluster activities, AGRHYMET has capacitated NMHSs in West Africa and the Sahel on this approach as a first step towards extended and widespread uptake and utilisation in NMHSs in the region. The capacity building event took place in Ouagadougou, Burkina-Faso from August 7th to 11th, 2023. The objective was to enhance the capacity of NMHSs to use new tools that combine seasonal forecasts with impact models in the agriculture and water resources sectors. This Info Note documents the process, key insights and lessons from the regional capacity building for translating seasonal forecasts into actionable information for agriculture and water sectors in West Africa for a better-informed policy and action decision making.

AGRHYMET Regional Climate Center for West Africa and Sahel (AGRHYMET-CCR-AOS), as part of its statutory mandate works to improve seasonal and sub-seasonal forecasting capabilities by using the NextGen approach (Houngnibo et al., 2022; Ali et al.; 2022). The NextGen forecasting system helps forecasters evaluate the performance of different global climate models, which helps determine how best to correct and combine them. It also helps forecasters select the best climate models for any region of interest through process-based evaluation, and it automates the generation and verification of forecasts suitable for multiple time scales at the regional, national, or local levels (Hansen et al., 2022). Through the Accelerating Impacts of CGIAR Climate Research for Africa (AICCRA) project, AGRHYMET Regional Climate Centre has been capacitating National Meteorological and Hydrological Services (NMHSs) in West Africa and the Sahel on NextGen seasonal forecasting systems. The capacity development efforts focus mainly on Python interface to the Climate Predictability Tool (CPT) or PyCPT, a tool developed by the International Research Institute for Climate and Society (IRI) to implement the NextGen approach to climate forecasting (Hansen et al., 2022). The continuous improvement of the PyCPT tool has recently enabled the integration of key characteristics of the rainy season such as the onset dates of the season, dry and wet sequences, and number of dry and wet days, in addition to total rainfall. While hydrological forecasts of water availability from watersheds in major river basins are essential to support operational planning and management, the latest version of PyCPT developed by IRI does not take into account the seasonal forecast of hydrological variables. A recent survey the NMHSs on the barriers to operationalization of the NextGen approach and use the PyCPT tool indicated that a key challenge limiting the operationalization and use the PyCPT tool was the lack of consideration of hydrologic parameters (Segnon et al., 2023).