tides

Wow! Measured / mapped from space by their (small) magnetic signature and shown sort of as animation: Earth's magnetic ocean tides mapped from space - Earth's magnetic ocean tides mapped

I have family that lives in New York City near a bay. If I want to do an exploratory dive there, what should I be looking at (ie. How do you evaluate a site you have never dove, and dont have any information about)? For example tides, current, boats, etc.. What tides are best for diving? Thanks!