Typhoon Hinnamnor rapidly intensified to the equivalent of a major hurricane on Monday morning. At 11:00 a.m. EDT on Monday the center of Typhoon Hinnamnor was located at latitude 27.3°N and longitude 140.4°E which put it about 835 miles (1345 km) east of Okinawa. Hinnamnor was moving toward the west at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h). The minimum surface pressure was 956 mb.

Typhoon Hinnamnor rapidly intensified to the equivalent of a major hurricane in a very favorable environment over the Western North Pacific Ocean northwest of Chichi Jima. A small circular eye 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 mass away from the typhoon. The removal of large quantities of mass allowed the surface pressure to decrease rapidly.

The circulation around Typhoon Hinnamnor was small. Winds to typhoon force extended out 30 miles (50 km) from the center of Hinnamnor. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Hinnamnor was 20.6. The Hurricane Size Index (HSI) was 9.2 and the Hurricane Wind Intensity Size Index (HWISI) was 29.8.

Typhoon Hinnamnor will move through an area favorable for intensification 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 is likely to continue to intensify rapidly during the next 24 hours. Hinnamnor could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Typhoon Hinnamnor will move around the southwestern part of a high pressure system that extends over Japan. The high pressure system will steer Hinnamnor toward the west during the 48 hours. On its anticipated track Typhoon Hinnamnor could approach the Ryukyu Islands in 48 hours. Hinnamnor will continue to produce strong gusty winds and locally heavy rain on Chichi Jima during the next few hours until it moves farther away. Typhoon Hinnamnor is likely to be the equivalent of a major hurricane when it approaches the Ryukyu Islands.