High-impact weather events, such as extreme rainfall, severe storms, damaging winds, landfalling atmospheric rivers, hurricanes/typhoons, heatwaves, and droughts, have significant impacts on our society and daily life. Data assimilation (including AI applications for data assimilation) and Research to Operations (R2O) play a crucial role in enhancing forecasts for high-impact weather events. This session will focus on recent research and advancements in atmospheric data assimilation, AI for data assimilation, and Research to Operations (R2O) aimed at improving forecasts for high-impact weather events, particularly those intended for operational and impact-oriented applications. We encourage submissions that explore various topics, such as advancements in data assimilation algorithms/techniques/systems, enhanced data preprocessing, assimilation of novel observation types, observational impact studies, synergies between artificial intelligence (machine learning) and data assimilation, Research to Operations (R2O) activities, the verification and validation of forecasts against theoretical frameworks and observational data, and other relevant studies.