What Factors Caused the Rapid Intensification Forecast Failure of the Hurricane Otis (2023) in Real-Time Operational Models?

Hurricane Otis made landfall in Acapulco, Mexico on October 25 as a category 5 hurricane with maximum sustained winds of 145 kt (74.6 m/s) and the lowest pressure of 923 hPa. Its powerful winds severely damaged many buildings in the city and torrential rain caused landslides and flooding. Otis is also attributed to at least 50 deaths and left 30 others missing, and billions of dollars in damages. From the forecaster point of view, almost all operational models provided inadequate forecast guidance and failed to predict the rapid intensification that Hurricane Otis underwent 24 hours before making landfall. In this study, we analyze forecasts from different real-time operational models to identify what factors have caused the rapid intensification forecast failure of Otis. We aim to investigate environmental and intrinsic vortex dynamical processes that prevent the rapid intensification in the operational models. By using the Hurricane Analysis and Forecast System (HAFS), we first evaluate the model sensitivity of forecasting rapid intensification to different horizontal and vertical resolutions and physical processes. We then provide a dynamic explanation on how the rapid intensification occurred in such a packed storm through analyzing large eddy simulations. A possible approach to improving rapid intensification forecast ability in the operational HAFS is proposed.