There has been for several years a nice way to look at marine weather from a conventional NWS presentation, which we have written up in the past in an article called "War Horses and Secret Sources." It is still there, but it seems to be expanded now to the Caribbean and maybe farther. It is still a bit of a secret (ie you do not find it on any marine weather page from NWS), but this service has some nice presentations for mariners.
Start by going to this link, which you can bookmark as from here you can get to other coastal waters or oceans. I am still now sure where the home page is for this interface.
At this page you will see several sections of data, but they are all tied to the point you can click in the small Google maps window on the bottom, which can be zoomed and panned. This sample is for waters north of Puerto Rico, which we have some interest in now.
This shows a 4 day (96 hr) forecast for ocean waters that is very similar to what we see on land forecasts, except this is wind and waves. Below this you will see:
Which is the text forecast for these days, giving more specifc info on wind and weather. If you are providing this to a friend, you can just copy the text and email it (see bottom sample from the Printable Forecast link). They will likely have something similar available underway, but it won't be quite so convenient. And on the bottom of the page you see the key window that is your graphic index to the point or series of points you care about.
Then for the location you selected you can get another view which might be called a "meterogram" for the area shown below which you get from selecting Hourly Weather Graph above.
This is worth checking out for the Caribbean or US coastal waters. It works great in comparing marine conditions in various parts of Puget Sound, SF Bay, or the Great Lakes... or parts of the Chesapeake. Just be sure you are zoomed in enough on the little map that you click on the water. If you click adjacent land you get the land forecast.
My guess is the foundation of the predictions is the GFS model, but it could be enhanced in some areas with more local model computations or input on some level.
A broader interface to this presentation is given at http://preview.weather.gov/graphical which is definitely a new and experimental web page. Seems a bit clunky yet, but the idea is good. In fact it was experimenting with this that made be realize that they have expanded the above presentation to the adjacent oceans, and that maybe this old way might be as convenient if not more.
Sample of the Printable Forecast