Mesoscale modeling investigation of air-sea interaction over the Gulf of Mexico for a case study of Hurricane Bret

Hurricane Bret was a Category 4 storm which formed in the western Gulf of Mexico on 21 August 1999. We are using the Penn State/NCAR MM5 modeling system for diagnostic studies of surface fluxes (sensible heat, latent heat, and momentum) over the Gulf of Mexico relevant to air-sea interaction in the vicinity of this intense hurricane. The MM5 configuration features two nested domains over the Gulf of Mexico, with horizontal grid spacing of 48 km and 16 km. Nesting between the grids is two way. Physics options selected include: nonhydrostatic; Grell cumulus parameterization on 48 km grid; explicit microphysics (Reisner) on 16 km grid; modified Mellor-Yamada boundary layer parameterization; and a cloud-resolving radiation scheme. Gridded analyses and rawinsonde data from NCAR were used to construct initial and boundary condition files. The model results will be discussed, along with relation to other theoretical and modeling studies of air-sea interaction in hurricane environments. Potential links between the model's surface fluxes and precipitation at landfall will be considered.