Due to warm water to the south of Mexico, Patricia intensified quickly to a category 5 hurricane. For it being so late in the hurricane season, this quick intensification is rarely observed in a tropical cyclone. The disturbance began near the Gulf of Tehuantepec and Patricia was classified a tropical depression on October 20th. At first, Patricia's development into a tropical cyclone was slow and took multiple weather systems. Patricia then entered an environment of very light winds in the upper atmosphere, high moisture, and greater instability over warm waters. It then strengthened into a hurricane on the evening of October 21st just south of Acapulco, Mexico.