Former Tropical Storm Koguma strengthened to a typhoon over the Western North Pacific Ocean east of the Northern Marianas on Thursday. At 5:00 p.m. EDT on Thursday the center of Typhoon Koguma was located at latitude 18.4°N and longitude 157.1°E which put the center about 810 miles (1310 km) east-northeast of Saipan. Koguma was moving toward the west-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 980 mb.
Former Tropical Storm Koguma strengthened to a typhoon on Thursday. The inner end of a rainband wrapped around the southern side of the center of Koguma’s circulation. Other bands of showers and thunderstorms were revolving around the center of Typhoon Koguma. Storms near the center of Koguma generated upper level divergence that pumped mass away from the typhoon. The removal of mass caused the surface pressure to decrease.
The distribution of wind speeds in Typhoon Koguma was fairly symmetrical. Winds to typhoon force extended out 30 miles (50 km) from the center of Koguma’s circulation. Winds to tropical storm force extended out 105 miles (165 km) from the center of Typhoon Koguma.
Typhoon Koguma will move through an environment that will be favorable for intensification during the next 24 hours. Koguma will move over water where the Sea Surface Temperatures are near 29°C. It will move under the southwestern part of an upper level ridge that is over the Central North Pacific Ocean. The upper level ridge will produce easterly winds that will blow toward the top of Koguma’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Typhoon Koguma will intensify during the next 24 hours. Koguma could strengthen to the equivalent of a major hurricane during the weekend.
Typhoon Koguma will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Koguma toward the west-northwest during the next 24 hours. On its anticipated track, Typhoon Koguma will pass northeast of the Northern Marianas.
Elsewhere over the Western North Pacific Ocean, Tropical Storm Nolo was weakening gradually far to the southeast of Japan.
At 5:00 p.m. EDT on Thursday the center of Tropical Storm Nolo was located at latitude 28.1°N and longitude 150.6°E which put the center about 855 miles (1380 km) east-southeast of Tokyo, Japan. Nolo was moving toward the west-northwest at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 991 mb.