An EOF analysis of instrumental December, January and February precipitation data has been perfomed. Its results have been used to identify the main modes of tropospheric vertically integrated moisture transport over the Mediterranean basin by means of the six hourly Reanalysis data. The moisture fluxes and their variability at each grid point and at the boundaries of the domain have been quantified. Some quantities related to the intensity of baroclinic disturbances have also been computed to help in the interpretation of the results. It is clear in the results that the leading mode of Mediterranean precipitation has its roots in the dynamics of the Atlantic storm--track and the associated moisture transports. The second mode, conversely, represents the internal redistribution of moisture inside the Mediterranean basin. Moisture is supplied to the atmosphere in the Genoa Gulf and this moisture is transported and precipitates over the Eastern Mediterranean (mainly Turkey and Greece). Finally, it is shown that the last factor depends on the role of European topography as a blocking factor for northern moisture transports advected from the North Atlantic region.