High seas and coastwise voice weather channels do a good job of telling you current weather conditions, and sometimes what's causing them ("High pressure stationed 200 miles east of Nova Scotia will give way to an approaching low now centered over Ohio..."). But the farther you are from a nearby harbor to duck into, the more you need to know exactly where the fronts are and where they're likely to go. There are several sources of on-board weather information. They're easy to use, and you don't need a Ph.D. in meteorology to understand them.
One possibility is weather fax, which lets you receive (and optionally print) the familiar black-and-white weather maps showing high and low pressure areas. You can continually receive weather fax on your computer, and view or print the current map only when you need it.
Once you have an SSB and a PC on board, a whole new world of communications -- voice, fax, e-mail -- is available to you.
The next step up is to use satellites as the primary source of information. Using satellites, you can access real-time, high-resolution, full-color satellite imagery. The information you can get boggles the mind -- and use of the data is free, once you have the antenna, software, and computer to grab it. Setting up for this technology is surprisingly inexpensive. OCENS, the prevailing software for the purpose, also utilizes SSB and the internet for acquiring information.