This paper deals with the limits in hydrodynamic and morphodynamic predictions for semi-enclosed coastal domains subject to sharp gradients (in bathymetry, topography, sediment transport and coastal damages). It starts with an overview of wave prediction limits (based on satellite images and buoy records) in a restricted domain, namely the Mediterranean basin, followed by an in-depth analysis of the Catalan coast, one of its land boundaries. The morphodynamic modelling for such regions is next discussed, based on the impact of a characteristic storm. The driving wave and surge conditions produce a morphodynamic response that is validated against the pre- and post-storm emerged beach state, recovered from two lidar images. The quality of the fit is discussed in terms of the physical processes and the suitability of the employed modelling suite. From here an assessment of errors and uncertainties is presented, with the aim of establishing the prediction limits for flooding and erosion analyses, key elements for coastal engineering decisions.