A coarse grid three-dimensional model of the west coast of Britain and a finer grid model of the eastern Irish Sea are used to examine the sensitivity of computed storm surge elevations and currents to the flow into the eastern Irish Sea in the regions to the north and south of the Isle of Man. Initial calculations of the storm surge of November 1977 show that meteorological forcing over the west coast of Britain is important in determining the inflow and currents in the eastern Irish Sea. Although an inflow event at 18h 11 November is not reproduced in the model, the outflows from the eastern Irish Sea which arise from a reduction in sea surface elevation following a storm are reproduced.A sensitivity study of currents within the eastern Irish Sea to inflows to the north and south of the Isle of Man suggests that the inflow found during the storm surge is a balance of these inflows. Also the inflows observed in the eastern Irish Sea are sensitive to the distribution of currents along the boundary to the South of the Isle of Man. The inability of the model to reproduce the location of the observed inflow can be corrected by adjusting the flow through the southern open boundary. However, in the absence of a more comprehensive set of measurements of currents in the eastern Irish Sea the role of inflows and outflows through the northern and southern open boundaries and how these contribute to the flows in the region cannot be determined.