All operational nowcasting products in HKO are archived to support the development of operational applications, verification, validation and research activities. Data in recent few years are stored on online or nearline storage systems with a total volume of around 500TB, such as Network Attached Storage (NAS) devices, providing fast and convenient access to the data. The interfaces of various nowcasting tools support automatic retrieval of products on user-specified date and time. Observation (radar and raingauge) data since SWIRLS operation in 1999 and nowcast products are archived on tapes for retrieval if needed.