The Bureau of Meteorology (BOM) broadcasts forecasts and warnings via:
The NSW Roads and Maritime Services (RMS) has an alert system that you can personalise. You can set alerts
The NSW Roads and Maritime Services (RMS) has web cam vision of certain coastal bars and other important locations.
Marine Rescue NSW, as well as many other organisations, will broadcast information on marine band radios.
Information on the latest coastal wave heights along the NSW coast provided by the Department of Public Works and Services Manly Hydraulics Laboratory.
Real time data for dams, rivers and streams is available from Water NSW.