While atmospheric rivers (ARs) play an important role in the hydrological cycle and are significant sources of water for the North American west coast, they can also bring extreme damage through heavy rain, flooding, and mudslides. Both ARs and the meteorological impacts of ARs are expected to become more impactful as our climate warms. Accurate climate model simulations of ARs are essential to understanding future AR impacts. Regional climate models provide an advantageous way to simulate ARs due to their ability to model in higher resolution with higher accuracy compared to a global climate model. This study utilizes the fifth version of the Regional Climate Modeling System (RegCM5) to simulate an AR case that occurred in 5-12 January 2017. RegCM5 has two different planetary boundary layer (PBL) schemes: Holtslag PBL (H PBL) and the University of Washington PBL (UW PBL); the objective of this study is to assess which scheme can most accurately simulate the AR and its resulting precipitation. We ran two different simulations keeping all parameterizations consistent except for the PBL scheme, and compared IVT and precipitation values to MERRA-2 Reanalysis data. Preliminary results show that H PBL and UW PBL perform similarly. H PBL tends to simulate slightly more precipitation than UW PBL. Both PBL schemes underestimate the magnitude and shape of IVT. Future work to further investigate optimal configurations include investigating convective parameterization schemes, simulating multiple case studies, and exploring different regions around the world.