Persistent phytoplankton bloom events, surface cooling, and associated fronts in the Strait of Ombai were seen by Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution Radiometer (AVHRR), and Synthetic Aperture Radar (SAR) imagery. It is suggested that the cooling events were caused by variable flow through the strait and its interaction with complex bathymetry. During the strongest cooling events a sharp, midstrait frontal feature was seen with a cross-front gradient in sea surface temperature (SST) of the order of 4¿C and a gradient in chlorophyll concentration of over 1 mg/m3. The frontal feature, associated with increased ocean color signal, extended, during major events, 100s of kilometers downstream of the strait and at times influenced nearly all of the Savu Sea. We show that variability in the bloom events can be tied to seasonal monsoons, ENSO, and their effect on thermocline depth.