We introduce the Explicit Wake Parametrisation (EWP) for wind farms in mesoscale models that accounts for the wake expansion within a turbine-containing cell. In the EWP approach, turbulence kinetic energy (TKE) production results from changes in vertical shear. The velocity recovery compares well to mast data downstream of the offshore wind farm Horns Rev I. The vertical structure of the TKE and the velocity profile are qualitatively similar to that simulated with large eddy simulations.