Motivated by recent work on Markov extremal models, we develop a nonstationary extension and use it to characterize the time evolution of extreme sea state significant wave height (H S ) and storm direction in the vicinity of the storm peak sea state. The approach first requires transformation of H S from a physical to a standard Laplace scale achieved using a nonstationary directional marginal extreme value model. The evolution of Laplace-scale H S is subsequently characterized using a Markov extremal model and that of the rate of change of storm direction described by an autoregressive model, the evolution variance of which is H S -dependent. Simulations on the physical scale under the estimated model give realistic realizations of storm trajectories consistent with historical data for storm trajectories at a northern North Sea location. © 2018 John Wiley & Sons, Ltd.