This study further evaluates the modeling approach of Jia et al. (2019) to investigate the potential effects of SST mesoscale variability on the atmospheric dynamics. The approach employs a global atmospheric circulation model coupled to a slab ocean model to produce two ensembles of simulations: one in which the ocean exhibits realistic SST mesoscale variability, and another in which the SST mesoscale variability is suppressed. The latter ensemble is produced by spatially filtering the SST analyses used for the estimation of the oceanic heat flux and the specification of the SST initial condition. The results of the present study, which focuses on the processes of the North Pacific, suggest that while the modeling approach yields the desired SST differences between the two ensembles at the mesoscales, it also introduces SST differences at the large scales that become the primary driver of the large scale differences in the simulated atmospheric flow. Diagnostics based on the eddy kinetic energy indicate that the large scale differences of the atmospheric flow lead to major differences in the dynamics of the jet stream and storm track. Because the large scale SST differences between the two ensembles are primarily driven by the differences between the prescribed estimates of the oceanic heat fluxes, finding a proper pair of those estimates is a necessary condition for the experiment design to detect the atmospheric response to SST mesoscale variability. The paper concludes with proposing a new strategy for the estimation of the oceanic heat fluxes.