Climatology and Common Aspects of Forecast Failures in Rapid Intensification of Atlantic Hurricanes

Forecasts failing to accurately predict tropical cyclone (TC) intensities, and specifically rapid intensification (RI) in TCs, is a major issue in current TC forecasting efforts (e.g. forecast uncertainty error in Debby (2024)). Improved TC intensity forecasts would ultimately help mitigate the effects of landfalling TCs by giving emergency managers more lead time to adequately prepare regions for landfalling TCs. This study first analyzes the climatology of RI forecast failures (cases in which periods of RI were not explicitly forecast) in Atlantic TCs by investigating the frequencies of RI forecast failures as functions of forecast hour and forecast year. Expectedly, 1) the results showed a general increase in the percentage of RI forecast failures as forecast hour was increased, and 2) longer-term improvement in RI forecast skill as the year was increased, although the overall skill remained low. A ± 5-degree latitude/longitude environment centered around each TC for cases of RI forecast failures and RI forecast successes was then retrieved from the time just before the RI occurred from the ECMWF ERA5 Reanalysis Dataset. Results showed that RI forecast failures occurred in environments characterized by lower 500/700mb RH, lower SSTs, and higher 200mb PV values than the environments around RI forecast successes.