Hurricane Dennis Simulation By Using Various Initial and Boundary Conditions with HRPS

In this paper, an attempt has been made to evaluate the performance of the Hurricane Research Prediction System (HRPS) developed at the Atlantic Oceanic and Meteorological Laboratory based on the sensitivity of different model domain sizes, and various background fields associated with forecasts for Hurricane Dennis. Dennis central pressure fell to 938 hPa with Dennis becoming a Category 4 hurricane on 8 July 1200 UTC. Heavy rainfall and flooding were the main threat from Dennis, resulting in one fatality. For the purpose of these experiments the nested Weather Research Forecasting (WRF) model was used with the Nonhydrostatic Mesoscale Model (NMM) dynamic core as a part of the emerging HRPS. To evaluate the influence of initial and lateral boundary conditions in the HRPS for hurricane simulations, experiments were performed over different domain sizes and a variety of model background fields. All hurricane track from each run were compared with the best track analysis released from National Hurricane Center (NHC). The computations are shown for the 120 hr period covering Dennis' period of rapid development starting on 6 July 2005 at 0000 UTC and ending on 11 July 2005 at 00 UTC. Grid spacing for the three specified moving nests were 18.9 and 6.6, respectively. Results from these simulations will be discussed in detail.