There is significant room for improvement in initializing the tropical cyclone and its surroundings for numerical forecasts. More sophisticated data assimilation schemes are required than those presently used, as new types of data become available. In this study, data from NASA's Quick Scatterometer (QuikScat) are assimilated using the 4-dimensional Variational (4d-Var) scheme, to provide analyses for MM5 model forecasts of the developing Hurricane Floyd. The influence of the data assimilation scheme and the new data on the MM5 forecasts will be presented. The potential for assimilating other types of data (such as AMSU) within the same framework will also be discussed.