Satellite infrared data show that the sea surface temperature pattern in the subtropical convergence consists of meridionally oriented alternating warm and cold plumes with a wavelength of about 200 km. In 1973, shipboard measurements during the Mid-Ocean Dynamics Experiment (Mode) revealed that the cold plumes resulted from southward advection of the surface water on the eastern flank of the Mode eddy and that the warm plumes were a result of northward advection on the western side. Along the edges of the plumes, small-scale frontogenesis was observed but was not resolved by the sampling scheme. Detailed measurements were made in March 1977 of the frontal structure at the southern end of a cold plume. These revealed the presence of smaller-scale motions with wavelengths of the order of 50 km. Temporal evolution of surface features in the vicinity and along the front occurred extremely rapidly and was barely resolved by surveys spaced 3--5 days apart.