Atmospheric rivers (ARs) are long, narrow, synoptic-scale moisture transport vehicles that straddle both weather and climate scales and fill an important role in Earth’s hydrological cycle. High resolution global modeling, in both atmosphere (~0.25^o) and ocean (~0.1^o), provides a better representation of atmospheric rivers, their structure, and precipitation characteristics, but, additionally and importantly, allows us to better understand feedbacks between the atmosphere and ocean associated with these features. Here, we analyze the high resolution version of the Community Earth System Model (CESM1.3, produced during the International Laboratory for High-Resolution Earth System Prediction - iHESP project ) with a focus on Pacific ARs impacting western North America. Several different experiments from the iHESP project are evaluated, including those employing the HighResMIP protocol, as well as all available historical and RCP8.5 climate change simulations. Two independent ARDTs (atmospheric river detection tools) are employed and chosen to represent different detection restrictiveness so that uncertainties in the AR frequency metric can be bounded and quantified. Preliminary results suggest that in the waters behind the AR, sea surface temperatures decrease while mixed layer depth increases. Sea surface height also responds to AR wind flow, falling in areas behind the AR but increasing closer toward the coast. Under climate change, these relationships strengthen, and for subtropical locations, warmer and shallower waters precede the AR.