Former Tropical Storm Jangmi strengthened to a typhoon on Saturday. At 11:00 a.m. EDT on Saturday the center of Typhoon Jangmi was located at latitude 19.7°N and longitude 128.8°E which put the center about 500 miles (805 km) south of Okinawa. Jangmi was moving toward the north-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 979 mb.
Former Tropical Storm Jangmi strengthened to a typhoon south of Okinawa on Saturday. A very large circular eye formed at the center of Typhoon Jangmi. The eye had a diameter of 70 miles (110 km). The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center Jangmi’s circulation. Storms near the center of Jangmi generated upper level divergence that pumped mass away from the typhoon. The removal of mass caused the surface pressure to decrease.
The circulation around Typhoon Jangmi was large. Winds to typhoon force extended out 90 miles (145 km) from the center of Jangmi’s circulation. Winds to tropical storm force extended out 205 miles (335 km) from the center of Typhoon Jangmi.
Typhoon Jangmi will move through an environment favorable for intensification during the next 24 hours. Jangmi will move over water where the Sea Surface Temperatures are near 29°C. It will move under the middle of an upper level ridge that is southwest of Japan. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear. Typhoon Jangmi will intensify during the next 24 hours.
Typhoon Jangmi will move around the western end of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Jangmi toward the north-northwest during the next 24 hours. On its anticipated track, Typhoon Jangmi will approach Okinawa in 36 hours.
Typhoon Jangmi will bring strong winds and locally heavy rain to the Ryukyu Islands including Okinawa. Heavy rain is could cause flash floods in some locations. Typhoon Jangmi could also cause a storm surge of up to 10 feet (3 meters) along portions of the coasts of the Ryukyu Islands.