Evaluating Tropical Cyclone Intensity Forecasts from HAFS Using Satellite-Derived Ocean Profiles

Abstract

As the ocean warms, tropical cyclones (TCs) may become more dangerous and costly for coastal communities since oceanic heat can increase TC intensity. Accurately modeling and forecasting TC intensity changes, especially from rapid intensification (RI) events, is challenging. Both RI and rapid weakening (RW) events can be strongly influenced by the heat content and stratification of the upper ocean, particularly for larger and slower-moving TCs. Better information about upper-ocean conditions can thus aid in the evaluation and potentially the improvement of RI/RW forecasts. The National Oceanic and Atmospheric Administration (NOAA) Next-Generation Enterprise Ocean Heat Content (NGE OHC) algorithm, an empirical parameterization, generates depth-resolved ocean temperature and salinity profiles that will be used operationally to estimate daily upper OHC fields and support detailed analysis of the potential oceanic contributions to RI/RW. The method leverages known ocean dynamics from relatively sparse in situ data to directly estimate profiles at high vertical and horizontal resolution from satellite data. In case studies from the 2020–22 Atlantic hurricane seasons, daily oceanic conditions from the NGE OHC are retrospectively compared with in situ Argo float observations, model initializations from the Hurricane Analysis and Forecast System (HAFS version 1.0B), and a current operational NOAA OHC product to illustrate how the NGE OHC would have helped improve the model’s initial ocean state in the Gulf of Mexico and Caribbean Sea. These comparisons show that many HAFS forecasts with intensity busts miss near-surface heat and barrier layers found in observations and the NGE OHC synthetic profiles.