The Global Information System Centres (GISC) is a major component of the WMO Information System(WIS) which operates a comprehensive metadata catalogue that is synchronized with the other GISCs. It holds a 24-hour cache with all data and products intended for global exchange, and it offers flexible subscription services for data and products. A GISC's primary role is to collect from and disseminate information to WIS centres in its area of responsibility and with the global WMO community. GISCs also provide search portals through which information from WMO and other interoperable systems can be discovered and accessed. The GISCs are connected through the WIS Core Network to ensure end-to-end delivery of warnings within two minutes of initialization.