The mesoscale thermodynamic, kinematic, and radar structure of a Hurricane Floyd rainband observed on 7 September 1981 is presented. Data are from 26 aircraft passes through the rainband from 150 to 6400 m. A composite technique which presents rainband structure as a function of distance from the storm circulation center reveals inflow from the outer edge of the band and a partial barrier to this flow below 3 km. In the direction parallel to rainband orientation, radar reveals cellular reflectivity structure on the upwind and central portions of the rainband; the frequency of cellular precipitation decreases in favor of stratiform precipitation further downwind as the band spirals gradually towards the eyewall. In the radial direction, a decrease of 12 K in e, is observed across the rainband in the subcloud layer. Convective scale up- and downdrafts that are associated with cellular reflectivity structure are hypothesized to be responsible for the thermodynamic modification of the cloud and subcloud layers.