The Monterey Bay Coastal Ocean (MB) nowcasting and forecasting system is based on a nested version of the Regional Ocean Modeling System (ROMS). The innermost (MB) domain encompasses the greater Monterey Bay region out to about 150 km offshore, with a horizontal resolution of approximately 300 m and 40 vertical levels. A multi-scale three-dimensional variational data assimilation (MS-3DVAR) methodology is used to produce the nowcast output shown here. A nowcast (or analysis) is produced every 6 hours at 03, 09, 15 and 21 UTC.