The western United States, and more specifically California, experiences some of the most episodic precipitation in the continental United States. Annual precipitation in this region is often derived from a few discrete extreme precipitation events, also known as atmospheric rivers (ARs), which are essential to meeting annual water demand yet are responsible for many of the historic flood events. The characteristics of ARs are often determined by a combination of dynamic and thermodynamic processes at various locations in the Pacific Ocean that ultimately influence the landfall location, the resulting intensity, duration, and frequency of precipitation and if the AR events act as a boon or bane on mountain snowpack reserves. New variable-resolution global climate models (VRGCMs) can capture the important global-to-regional scale interactions between atmosphere-land-ocean and telescope resolution where needed such as genesis regions (e.g., equatorial warm pools) and/or mountainous regions. Thus, VRGCMs resolve the complete lifecycle of the source-to-landfall of ARs which allows for the diagnosis of both the dynamic and thermodynamic processes that shape them. To date, the VRGCM community has yet to evaluate the implications of domain extent over the Pacific Ocean and its influence on AR lifecycles. This presentation will discuss ongoing research using variable-resolution in the Community Earth System Model (VR-CESM) and the TempestExtremes AR detection algorithm to assess the implications of varying longitudinal domain extent over the Pacific Ocean on the characteristics of ARs.