A comparison will be made between TRMM-derived and numerically simulated precipitation structure for hurricane Bret (August 1999). Based on observations conducted with airborne Doppler radars and release of dropwindsondes within 1,000 km, tangential, radial and vertical wind, temperature and humidity fields are blended with a large-scale analysis derived from ECMWF and are used as initial fields for the French "Méso-NH" non-hydrostatic mesoscale numerical model. This original initialization technique and the simulated structure and evolution obtained through this approach will be discussed at the 9th Conference on Mesoscale Processes.