A dense bottom overflow into a 100-km scale silled embayment has been observed for a 70-day period using a coherent array of current meters and thermistor chains. As the internal Rossby radius is less than the width of the bay, the overflow is controlled by rotational dynamics. The flow is strongly modulated by the tide at diurnal, semi-diurnal and fortnightly periods. This causes a series of cold temperature fronts, associated with separate overflow events, to pass through the mooring array. The overflow is also modulated at periods of 2–3 days. This appears to be associated with the interaction of the density current with bottom-trapped waves, or possibly with interior basin modes. It appears that the forcing of the oscillation is associated with the wind, which also contains a 3-d signal.