Typhoon Khanun Brings Wind and Rain to Okinawa

Typhoon Khanun brought wind and rain to Okinawa on Tuesday. At 5:00 p.m. EDT on Tuesday the center of Typhoon Khanun was located at latitude 25.7°N and longitude 127.1°E which put it about 50 miles (80 km) south-southwest of Okinawa. Khanun was moving toward the west-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 941 mb.

Typhoon Khanun brought strong, gusty winds and locally heavy rain to Okinawa on Tuesday. The eye and eyewall at the center of Khanun’s circulation passed just south of Okinawa. Bands in the northern part of Typhoon Khanun moved across Okinawa. A weather station at Kadena Air Force Base reported a sustained wind speed of 74 m.p.h. (119 km/h). The weather station reported a wind gust to 87 m.p.h. (141 km/h).

An eye with a diameter of 25 miles (40 km) was at the center of Typhoon Khanun. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Khanun. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Khanun was large. Winds to typhoon force extended out 65 miles (105 km) from the center of Khanun’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Khanun was 23.6. The Hurricane Size Index (HSI) was 18.2 and the Hurricane Wind Intensity Size Index (HWISI) was 41.8. Khanun is capable of causing regional major damage. Typhoon Khanun was as strong as Hurricane Dennis was when Dennis hit Northwest Florida in 2005. Khanun was much larger than Dennis was.

Typhoon Khanun will move through an environment that will become less favorable for a strong typhoon during the next 24 hours. Khanun will move over water where the Sea Surface Temperatures are near 28˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. However, there is a region of drier air northwest of the Ryukyu Islands. Some of the drier air could get pulled into the western half of Typhoon Khanun. The drier air is likely to cause Typhoon Khanun to weaken during the next 24 hours. Khanun is likely to move slowly during the next few days. Strong winds near the surface will mix cooler water to the surface of the ocean. Typhoon Khanun will extract less energy from the ocean and it is likely to continue to weaken later this week.

Typhoon Khanun will move around the southwestern side of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Khanun toward the west-northwest during the next 24 hours. On its anticipated track, the core of Typhoon Khanun move west of Okinawa during the next 24 hours. The steering currents are likely to weaken later this week and Typhoon Khanun could meander near the Ryukyu Islands for several days. Khanun will continue to bring strong, gusty winds and locally heavy rain to Okinawa and the other southern Ryukyu Islands. Heavy rain will cause flash floods in some locations. Typhoon Khanun will also cause a significant storms surge in the parts of islands where the winds blow water toward the coast.