Prediction of Landfalling Hurricanes with the Advanced Hurricane WRF Model

TLDR

Real‑time forecasts of five 2005 Atlantic hurricanes with the Advanced Research WRF model at 12‑ and 4‑km resolution were generally competitive with, and sometimes superior to, other operational forecasts for storm position and intensity. The study aimed to correct recurring forecast errors by designing and testing augmentations to create the Advanced Hurricane WRF (AHW) model. The AHW model incorporated corrections for excessive pre‑landfall intensification, insufficient surface momentum exchange, and failure to capture rapid intensification, and was evaluated at multiple grid spacings. Sensitivity runs with Katrina revealed that eye size and inner‑core structure are resolution‑dependent, rapid intensification and convective band structure improved only near 1‑km spacing, and coupling to a mixed‑layer ocean model largely eliminated the pre‑landfall intensification error.

Abstract

Abstract Real-time forecasts of five landfalling Atlantic hurricanes during 2005 using the Advanced Research Weather Research and Forecasting (WRF) (ARW) Model at grid spacings of 12 and 4 km revealed performance generally competitive with, and occasionally superior to, other operational forecasts for storm position and intensity. Recurring errors include 1) excessive intensification prior to landfall, 2) insufficient momentum exchange with the surface, and 3) inability to capture rapid intensification when observed. To address these errors several augmentations of the basic community model have been designed and tested as part of what is termed the Advanced Hurricane WRF (AHW) model. Based on sensitivity simulations of Katrina, the inner-core structure, particularly the size of the eye, was found to be sensitive to model resolution and surface momentum exchange. The forecast of rapid intensification and the structure of convective bands in Katrina were not significantly improved until the grid spacing approached 1 km. Coupling the atmospheric model to a columnar, mixed layer ocean model eliminated much of the erroneous intensification of Katrina prior to landfall noted in the real-time forecast.