  Wind turbines operate in the atmospheric boundary layer (ABL), where Coriolis
effects are present. As wind turbines with larger rotor diameters are deployed,
the wake structures that they create in the ABL also increase in length.
Contemporary utility-scale wind turbines operate at rotor diameter-based Rossby
numbers, the nondimensional ratio between inertial and Coriolis forces, of
O(100) where Coriolis effects become increasingly relevant. Coriolis forces
provide a direct forcing on the wake, but also affect the ABL base flow, which
indirectly influences wake evolution. These effects may constructively or
destructively interfere because both the magnitude and sign of the direct and
indirect Coriolis effects depend on the Rossby number, turbulence, and buoyancy
effects in the ABL. Using large eddy simulations, we investigate wake evolution
over a wide range of Rossby numbers relevant to offshore wind turbines. Through
an analysis of the streamwise and lateral momentum budgets, we show that
Coriolis effects have a small impact on the wake recovery rate, but Coriolis
effects induce significant wake deflections which can be parsed into two
regimes. For high Rossby numbers (weak Coriolis forcing), wakes deflect
clockwise in the northern hemisphere. By contrast, for low Rossby numbers
(strong Coriolis forcing), wakes deflect anti-clockwise. Decreasing the Rossby
number results in increasingly anti-clockwise wake deflections. The transition
point between clockwise and anti-clockwise deflection depends on the direct
Coriolis forcing, pressure gradients, and turbulent fluxes in the wake. At a
Rossby number of 125, Coriolis deflections are comparable to wake deflections
induced by 17{\deg} of yaw-misalignment.
