Data from the Seasat scatterometer are assimilated into the ECMWF analysis-forecast model. To assess the impact of using Seasat A satellite scatterometer (SASS) data, comparison is made between analyses which use this data type and those which do not, as well as between forecasts from these analyses. The differences in the northern hemisphere are found to be small, but sizeable differences occur in the southern hemisphere. Some synoptic comparisons are made between SASS data and the model analyses, as well as data impact on forecasts for the QE-II and Ark Royal storms. ¿ American Geophysical Union 1991