Like most other national weather services the Swedish Meteorological and Hydrological Institute (SMHI) was established in the late 19th century. The reason for this was the development of the telegraph. In order to make a weather forecast one need information about the current weather situation within a large area and the telegraph made this possible. As an illustration; todays 24 hour weather forecasts for Sweden use information from all of Europe; the northern Atlantic as well as the eastern parts of northern America. Accordingly SMHI gathers vast quantities of data around the clock from land-based weather stations; balloons; ships; buoys; aircraft; weather radar; satellites and lightning localization systems. This information is the base for further processing in complex numerical models; tailored for applications in meteorology; hydrology and oceanography (MHO).