From 6 January to 28 February 1997, a unique experiment, involving 11 countries from both sides of the Atlantic (including three non-EU countries), was set up to study the formation and life cycles of storms and frontal cloud systems over the North Atlantic. The FASTEX (Fronts and Atlantic Storm-Track Experiment) project, which is supported by the Community's specific research programme in the field of Environment and Climate, involved simultaneous observations of weather conditions from buoys, ships, aircraft and satellites. The quantity and quality of the data sets obtained are unique and will allow scientists to forecast storms several days in advance with better accuracy. Despite improvements in weather forecasting techniques over the last 20 years, heavy rain, winds and storms are often forecast inaccurately. One of the main reasons is the difficulty in identifying precursors of the storms, especially for cyclones born over oceans, where there are few observing systems as compared to land areas. In addition, numeric weather forecast models are far from being perfect and complex cloud processes are still not well understood. The aim of FASTEX is to improve both storm forecasts and climate predictions, both by observation of storm tracks and through better understanding of their intensification mechanisms. During the operational phase in January and February, conducted at Shannon Airport, Ireland, 46 cyclones occurred in the FASTEX area, of which 19 were monitored and analysed in detail. The data sets obtained include a wide spectrum of cyclones including small to large, of different intensity and developing time (slow and fast). The analyses of these unique data will help to improve understanding of the life cycles and storm tracks of North Atlantic cyclones, their inter-relationship with, and their impact on, European climate.