The 2023 NOAA Hazardous Weather Testbed Spring Forecasting Experiment What: Within a hybrid framework of in-person and virtual participation, over 125 forecasters and researchers engaged in real-time, experimental severe weather forecasting activities and model evaluations, which included 1) the Rapid Refresh Forecast System, 2) the Model for Prediction Across Scales, 3) the Warn-on-Forecast System, and 4) innovative postprocessing strategies. When: 1 May-2 June 2023 Where: Norman, Oklahoma, and Online. [ABSTRACT FROM AUTHOR]