This chapter aims at gaining new insights on the surface and intermediate dynamics of the Tyrrhenian Sea (TYS), through the analysis of the results produced in the first year of life of an operational, high-resolution model of the TYS circulation. The regional ocean model has been developed in the context of PRogetto pilota Inquinamento Marino da Idrocarburi (PRIMI), a national project funded by the Italian Space Agency (ASI), aimed at the realization of a prototypal system for monitoring and forecasting the evolution of oil spills in the Italian seas. During 2009, the model has produced both weekly forecasts and hindcasts. First, the chapter describes the basic features of the operational model of the TYS. Next, it explains the weekly hindcasts produced by the model. The chapter further characterizes the seasonal variability of the surface and intermediate circulation in 2009. Finally, the main aspects of water masses distributions are discussed. © 2014 American Geophysical Union.