Typhoon Hinnamnor intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale over the Western North Pacific Ocean near Minami Daito Jima on Tuesday afternoon. At 5:00 p.m. EDT on Tuesday the center of Typhoon Hinnamnor was located at latitude 26.1°N and longitude 131.2°E which put it about 55 miles (90 km) east-northeast of Minami Daito Jima and about 255 miles (410 km) east of Okinawa. Hinnamnor was moving toward the west at 18 m.p.h. (29 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h). The minimum surface pressure was 915 mb.

Powerful Typhoon Hinnamnor was the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday afternoon. A circular eye with a diameter of 10 miles (16 km) was at the center of Hinnamnor’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Hinnamnor. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the typhoon. The removal of large quantities of mass allowed the surface pressure to decrease.

The circulation around Typhoon Hinnamnor contracted in size when the typhoon intensified to Category 5. Winds to typhoon force extended out 25 miles (40 km) from the center of Hinnamnor. Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Hinnamnor was 35.0. The Hurricane Size Index (HSI) was 8.8 and the Hurricane Wind Intensity Size Index (HWISI) was 43.8. Hinnamnor was capable of causing regional catastrophic damage.

Typhoon Hinnamnor will move through an environment capable of supporting a strong typhoon during the next 24 hours. Hinnamnor will move over water where the Sea Surface Temperatures are 30˚C. It will move through region where the winds at all levels of the troposphere are blowing from the east. Since the winds at different levels are blowing from the same direction, there will be little vertical wind shear. Typhoon Hinnamnor could maintain much of its intensity during the next 24 hours, if the inner end of rainband does not wrap around the existing eye and eyewall. If concentric eyewalls form, then an eyewall replacement cycle could cause Typhoon Hinnamnor could to weaken temporarily.

Typhoon Hinnamnor will interact with Tropical Depression 13W that formed southeast of Okinawa during the next 24 hours. At 5:00 p.m. EDT on Tuesday morning center of Tropical Depression 13W was located at at latitude 20.5°N and longitude 133.0°E which put it about 555 miles (895 km) southeast of Okinawa. The tropical depression was moving toward the north at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1000 mb.

Typhoon Hinnamnor will move toward the west-southwest during the next 24 hours when its circulation interacts with the tropical depression. On its anticipated track the core of Typhoon Hinnamnor will be near Minami Daito Jima in a few hours. Hinnamnor could cause catastrophic wind damage on Minami Daito Jima. Very heavy rain could cause flash floods. Typhoon Hinnamnor will also cause a significant storm surge along the coast of Minami Daito Jima. Widespread electrical outages are likely. The center of Hinnamnor could be southeast of Okinawa in 12 hours.

Typhoon Hinnamnor will eventually absorb the circulation around the tropical depression. Hinnamnor could move slowly around the southern Ryukyu Islands while it absorbs the depression. A prolonged period of strong winds and heavy rain could affect the southern Ryukyu Islands later this week.