Typhoon Khanun Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Khanun rapidly intensified to the equivalent of a major hurricane southeast of Okinawa on Sunday. At 11:00 p.m. EDT on Sunday the center of Typhoon Khanun was located at latitude 22.3°N and longitude 133.7°E which put it about 405 miles (655 km) southeast of Okinawa. Khanun was moving toward the north-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 948 mb.

Typhoon Khanun rapidly intensified to the equivalent of a major hurricane on Sunday. A circular eye with a diameter of 30 miles (50 km) was at the center of Khanun’s circulation. 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 strong upper level divergence that pumped mass away form the typhoon in all directions. The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Khanun was large. Winds to typhoon force extended out 70 miles (110 km) from the center of Khanun’s circulation. Winds to tropical storm force extended out 290 miles (465 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Khanun was 22.1. The Hurricane Size Index (HSI) was 26.1 and the Hurricane Wind Intensity Size Index (HWISI) was 48.2. Typhoon Khanun was similar in size and intensity to Hurricane Jeanne when Jeanne hit Florida in 2004.

Typhoon Khanun will move through an environment that will be favorable for intensification during the next 24 hours. Khanun will move over water where the Sea Surface Temperatures are near 29˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Khanun is very likely to intensify during the next 24 hours. Khanun could intensify rapidly at times.

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 northwest during the next 24 hours. On its anticipated track, Typhoon Khanun will move toward the Ryukyu Islands. The center of Khanun could be just south of Okinawa in 36 hours.