Typhoon Caitlin, known in the Philippines as Typhoon Ising, contributed to major drought relief in Okinawa. A tropical disturbance formed in the middle of July 1991 in the eastern portion of the Western Pacific monsoon trough, and while tracking to the west-northwest, was designated a tropical depression on July 21. Thunderstorm activity associated with the depression increased markedly on July 22, and two days later, the depression was upgraded into Tropical Storm Caitlin. The storm turned northward as it rounded a subtropical ridge while gradually intensifying. Caitlin became a typhoon on July 25 and peaked in intensity on July 27 near Okinawa. The typhoon began to weaken as it turned northeast over the Korea Strait. On July 30, Catlin transitioned into an extratropical cyclone as it ent