High-Resolution Simulation of Hurricane Patricia (2015): Rapid Intensification

Hurricane Patricia (2015) was one of the most intense hurricanes in the history of the western hemisphere, reaching 185 kt and 872 hPa at its peak intensity (Kimberlain et al. 2016). In particular, Patricia developed into a category-5 hurricane from a tropical storm in 24 h at a rate rarely observed. In this study, the rapid intensification (RI) of Patricia was examined using the Coupled Ocean/Atmosphere Mesoscale Prediction System – Tropical Cyclone (COAMPS-TC®) simulation with a 0.889-km grid spacing initialized at 1800 UTC 21 October, 42 h before the observed storm reached peak intensity. COAMPS-TC performed reasonably well for Patricia track forecast and successfully captured its peak intensity. While the intensification rate is similar between the best track and the forecast, the storm reached its peak intensity ~12 h later in the forecast than the observed, associated with the delayed movement of the forecast storm into the warm sea surface temperature (SST) region. The high resolution simulation produced a small eye (13-18 km) during the RI, the same size as the observed eye. The environmental analysis suggested that that abnormally warm SST (>30^oC) and strong upper level divergence were conducive for Patricia’s RI. Sensitivity tests with various grid spacing indicate high sensitivity of storm peak intensity to grid resolution. Our simulations demonstrate the capability of operational COAMPS-TC of forecasting Patricia’s extreme RI at high resolution.