A system for sending an effective warning signal to receivers in a predetermined area. A transmitter, activated by a local authority, sends a severe weather warning signal to a plurality of receivers. Cities or counties within the predetermined area are divided into subdivisions thereof called sectors, each of which represents an area that is selectively addressable by the transmitter. Each of the receivers has a programmable sector code which has been programmed according to the location of the home or office in which it is placed. When activated, the transmitter sends radio frequency warning signals which contain digitally encoded information indicating the sector to which the warning applies. Upon receiving the warning signal, each receiver that has been programmed with the sector code being transmitted responds by generating an audible alert or other warning signal. In one embodiment, the transmitter sending the warning signal is connected to, and activated by, the same mechanism that activates a corresponding warning siren.