Typhoon Prapiroon brought wind and rain to Okinawa on Sunday. At 5:00 p.m. EDT on Sunday the center of Typhoon Prapiroon was located at latitude 26.8°N and longitude 126.8°E which put it about 65 miles (100 km) west-southwest of Okinawa. Prapiroon was moving toward the north at 10 m.p.h. (16 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 978 mb.
The circulation of former Tropical Storm Prapiroon became much more well organized on Sunday. A circular eye formed at the center of circulation and Prapiroon strengthened into a typhoon. A ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Several bands of showers and thunderstorms in the eastern half of the typhoon were revolving around the center of circulation. Bands northwest of the center consisted mostly of showers and low clouds. Storms in the core of the circulation were generating upper level divergence which was pumping mass away to the east of the typhoon.
Typhoon Prapiroon will move through an environment favorable for intensification during the next 12 to 24 hours. Prapiroon will move over water where the Sea Surface Temperature is near 29°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Prapiroon could intensify during the next 12 to 24 hours. Prapiroon will move over cooler water in a day or so. It will also reach a location where an upper level trough west of South Korea will cause more vertical wind shear. An environment of cooler water and more wind shear will cause Typhoon Prapiroon to weaken at that time.
Typhoon Prapiroon is moving around the western end of a subtropical ridge which is steering it toward the north. On its anticipated track the center of Typhoon Prapiroon will pass west of Okinawa and the northern Ryukyu Islands. Winds to typhoon force extend out about 30 miles (50 km) east of the center of circulation. Winds to tropical storm force extend out about 150 miles (240 km) east of the center. So, even though the center of Typhoon Prapiroon will pass west of the northern Ryukyu Islands, it will bring gusty winds and heavy rain. Typhoon Prapiroon could approach western Kyushu in 24 hours. When Prapiroon moves farther north the trough west of South Korea will start to steer the typhoon more toward the northeast.