Forecasts tend to represent a statistical average based on interpretation of current and historic data. The larger the data sample and the larger the forecast area the higher accuracy probability.
So, assemble as much available information; TV and radio stations, National Weather Service, buoy data and your own past experience in your home waters then make a somewhat educated guess. But keep watching the sky.
1970 Havsfidra 20 by Fisksatra
On the Delaware River at Fox Grove Marina Essington PA