The track was erratic because the storm had not yet separated from the monsoon trough. By June 30, Chataan had steadily strengthened to severe tropical storm status, with 10-minute maximum sustained winds of 95 km/h (60 mph). Only July 1, the system's circulation became broad, with most of the convection located west of the center. The next day, Chataan briefly weakened to an intensity of 85 km/h (50 mph), although it began strengthening steadily on July 3, when its center passed very near Weno in Chuck State in the FSM. At 1800 UTC that night, the JTWC upgraded Chataan to a typhoon, and about 24 hours later the JMA followed suit while the storm was approaching Guam from the southeast. At about 2130 UTC on July 4, the eye of Chataan moved across northern Guam in about two hours, although the center of the eye passed north of the island. After affecting Guam, Chataan continued toward the northwest and gradually intensified. At 0000 UTC on July 8, the typhoon reached its peak intensity of 175 km/h (110 mph 10-minute sustained) while located near the Japanese island of Okinotorishima. The JTWC assessed that Chataan had reached its peak intensity of 240 km/h (150 mph 1-minute sustained) about six hours earlier; on that basis, the agency classified the system as a super typhoon. On July 8, Chataan turned toward the north around the subtropical ridge while maintaining its peak winds for about 18 hours. On July 9 the typhoon turned to the northeast, and late that day it weakened to a severe tropical storm. At around 1530 UTC on July 10, Chataan made landfall on the Bōsō Peninsula in Honshu with winds of about 100 km/h (65 mph 10-minute sustained). The storm briefly moved offshore before making a second landfall on eastern Hokkaido at 1200 UTC on July 11; this marked the first occasion of a July landfall on the island in 28 years. A few hours later, Chataan became an extratropical cyclone in the Sea of Okhotsk, where the remnants stalled before dissipating on July 13 near Sakhalin. Preparations and impact Federated States of Micronesia While Chataan was in its formative stages and still tied to the monsoon trough, it produced a large area of heavy rainfall and strong winds that affected Pohnpei and Chuuk in the FSM. The storm passed very near Chuuk with wind gusts of 82 km/h (51