The Sea Surface Temperature (SST) is a required field in Numerical Weather Prediciton (NWP) systems because it functions as the lower boundary condition for the calculation of air-sea heat fluxes. The GFS Simple Ocean Scheme does not change the SST. Therefore, the SST stays constant throughout the forecast unless it is updated by other processes. In some models, such as the UFS atmosphere, the SST can change if forcing towards the climatology is turned on.