The OPTOMA (Ocean Prediction Through Observations, Modeling and Analysis) Program, a joint NPS/Harvard program sponsored by ONR, seeks to understand the mesoscale (fronts, eddies, jets) variability and dynamics of the California Current System and to determine the scientific limits to practical mesoscale ocean forecasting. To help carry out the aims of this project, a series of cruises has been planned in two subdomains, NOCAL and CENCAL. The cruise OPTOMA1 was undertaken, on the R/V ACANIA, in March, 1982 and covered part of the NOCAL domain which is roughly 200 km square centered 150 km off the California coast. From March 8 to 13, hydrographic data were acquired along a series of tracks. In the rectangular domain, roughly 90 km across-shore by 120 km alongshore, the series of parallel transects directed alonshore were separated by about 18 km. Along-track station spacing was about 8.8 km. In addition, there were tracks to and from the domain.