P63 Diagnostic Studies of Tropical Cyclone/Hurricane Activity over the Gulf of Mexico Using Numerical Models and Satellite Data

Reddy, Remata, Duanjun Lu and Mehri Fadavi, Jackson State University, Jackson, Mississippi

Understanding the genesis, evolution and intensity/track of tropical cyclones is limited by a shortage of observations and knowledge of key processes (atmospheric, oceanic and air-sea interactions). This research focuses diagnostics studies of the observational and numerical investigations of the air-sea interactions, tropical cyclone intensity change and track forecast associated with landfall of tropical cyclones. The satellite, buoy and aircraft data for meteorological observations were used to compute surface fluxes (heat, momentum and latent heat) for understanding the structure and dynamics of the hurricane activity associated with air-sea interactions over the Gulf of Mexico. The study for hurricane Opal suggested strong heat flux before and during the formation of the hurricane with an evidence of 2-5 day oscillations in heat flux. Primitive Models (Hurricane Predictive Index (HPI) and Linear Regression) were developed for intensity change forecasts and early warning systems and were tested for two hurricane cases (Opal, 1995 and Katrina, 2005). Numerical model (WRF/ARW) with data assimilations have been used for this research to investigate the sea-air interactions associated with the hurricane Katrina, which began to strengthen until reaching Category 5 on 28 August 2005. The model was run on a doubly nested domain centered over the central Gulf of Mexico, with grid spacing of 90 km and 30 km for 6 hr periods, from August 28th to August 30th. The model output was compared with the observations and is capable of simulating the surface features, intensity change and track associated with hurricane Katrina. The study suggested strong heat and latent heat fluxes with heavy rainfalls, as with Katrina, changes hurricane intensity while making land fall.