Toward a nowcast/forecast system for water levels in the Chesapeake Bay

The Model for Estuarine and Coastal Circulation Assessment (MECCA) is currently being used in an experimental nowcast/forecast scheme aimed at enhancing National Ocean Service predictions of water level within the Chesapeake Bay. Winds and water levels observed at the Chesapeake Bay Bridge Tunnel (CBDT) are used in combination with winds observed at Thomas Point Light to produce a twice daily nowcast of the water level within the bay. These nowcasts provide initial conditions for forecast runs as well as providing water level information throughout the bay rather than lust at tide gauge locations. Tests of predictive capabilities have included driving MECCA with forecasts of subtidal water level at the open boundary and forecast wind fields that will be available operationally. The quality of the water level forecast is highly dependent upon the accuracy of both the open boundary condition and windfield forcing conditions.