What system is appropriate for local storm warnings where it is inappropriate to alert all ships in the satellite coverage area?

The correct answer relates to the Enhanced Group Call (EGC) system, which is designed specifically for disseminating navigational and safety messages to ships at sea. EGC operates through Inmarsat satellite communications and allows for targeted broadcasts to specific geographic areas, making it ideal for local storm warnings.

In scenarios where alerts should not go out to all ships within a satellite's coverage area, EGC lets operators send messages to select vessels or groups of vessels based on their position. This capability is invaluable during localized severe weather events, as it minimizes unnecessary alarm among ships that might not be in immediate danger.

The other systems mentioned are focused on different aspects of maritime communication. NAVTEX provides navigational and meteorological information, but it broadcasts to all vessels within a certain range and may not allow for the same level of specificity as EGC. AMVER is a voluntary program for tracking vessels to aid in search and rescue operations, rather than for delivering real-time weather warnings. DSC (Digital Selective Calling) is primarily used for distress communication and does not include dissemination of storm warnings in the localized manner that EGC facilitates.