Severe Tropical Cyclone Osea was the second of seven cyclones to affect French Polynesia during the 1997–98 South Pacific cyclone season. The fourth tropical cyclone and second severe tropical cyclone of the very active season, Osea began as a low that formed on November 22, and the storm initially remained weak. Moving south and later east, it was named Osea on November 24 after achieving windspeeds equal to a Category 1 cyclone on the Australian tropical cyclone intensity scale. Continuing to intensify, Osea soon reached its peak intensity of 90 mph (145 km/h). Afterwards, Osea began to weaken because of increased wind shear, and the cyclone started moving southeast. By November 28, Osea was no longer a tropical cyclone.