At the beginning of the 20th century Vilhelm Bjerknes defined the “ultimate problem ofmeteorology and hydrography” as the discovery of “the laws according to which an atmo-spheric or hydrospheric state develops out of the preceding one” and the “precalculation offuture states” from gridded analyzed observations—that is, forecasting. The development ofthe electronic computer and the vision of several meteorologists allowed the transformationof meteorology into a sophisticated scientific discipline based on physics and mathematics.The first successful meteorological forecast was carried out in the 1950s. Meteorologicalforecasting became an operational activity at the end of the 1960s. The contributions tosociety of such operations have been tremendous.