The Ocean Vital Signs Network System Design (OVSN SD) Team will advance OVSN modeling and data system priorities including (1) Skill assessment of current models and state estimates (2) data platform design and implementation (3) advancing regional numerical modeling of the Northwest Atlantic and (4) Model-based assessment for planning regional-scale observing strategies. The team will build a foundation for the design of an OVSN Northwest Atlantic Testbed, working closely with both internally and externally funded OVSN activities and sub-projects.