Typhoon Hinnamnor Moves South of Okinawa

Typhoon Hinnamnor moved south of Okinawa on Wednesday. At 11:00 a.m. EDT on Wednesday the center of Typhoon Hinnamnor was located at latitude 24.4°N and longitude 127.3°E which put it about 115 miles (185 km) south of Okinawa. Hinnamnor was moving toward the west-southwest at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 175 m.p.h. (280 km/h). The minimum surface pressure was 929 mb.

Concentric eyewalls developed at the center of Typhoon Hinnamnor on Tuesday night. The original eye with a diameter of 10 miles (16 km) was still present at the center of Hinnamnor. The inner end of a rainband wrapped around the original eye and eyewall. An outer eye with a diameter of 60 miles (95 km) surrounded the original eye and eyewall. Typhoon Hinnamnor weakened slightly as the winds in the inner eyewall decreased slightly. The core of Hinnamnor still generated strong upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Hinnamnor increased when the concentric eyewalls developed. Winds to typhoon force extended out 35 miles (55 km) from the center of Hinnamnor. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Hinnamnor was 29.9. The Hurricane Size Index (HSI) was 13.4 and the Hurricane Wind Intensity Size Index (HWISI) was 43.3. Hinnamnor was capable of causing regional severe 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. Even though it will be in a favorable environment, Typhoon Hinnamnor will weaken as the inner eyewall weakens because of the eyewall replacement cycle. More of the low level inflow will become concentrated in the outer eyewall. Hinnamnor could strengthen again after the eyewall replacement cycle is completed.

Typhoon Hinnamnor will interact with Tropical Depression 13W that is located southeast of Okinawa during the next 24 hours. At 11:00 a.m. EDT on Wednesday morning center of Tropical Depression 13W was located at at latitude 22.6°N and longitude 131.6°E which put it about 400 miles (640 km) southeast of Okinawa. The tropical depression was moving toward the north-northwest at 14 m.p.h. (22 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 moved toward the southwest during the next 24 hours as it moves around the western side of Tropical Depression 13W. On its anticipated track, Typhoon Hinnamnor will move south of the southern Ryukyu Islands. The much stronger circulation around Typhoon Hinnamnor will eventually absorb the weaker tropical depression. Hinnamnor could be in an area where the steering winds are weak after it absorbs the tropical depression. Typhoon Hinnamnor could meander near the southern Ryukyu Islands later this week.