Typhoon Koguma was spinning over the Western North Pacific Ocean east of Iwo To on Saturday night. At 11:00 p.m. EDT on Saturday the center of Typhoon Koguma was located at latitude 24.9°N and longitude 148.0°E which put the center about 435 miles (700 km) east of Iwo To. Koguma was moving toward the northwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h). The minimum surface pressure was 944 mb.
Typhoon Koguma intensified on Saturday. Koguma was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale. A circular eye with a diameter of 23 miles (37 km) was at the center of Typhoon Koguma. 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 revolved around the center of Koguma’s circulation. Storms near the center of Koguma generated upper level divergence that pumped mass away from the typhoon. The removal of mass caused the surface pressure to decrease on Saturday.
The distribution of wind speeds in Typhoon Koguma was fairly symmetrical. Winds to typhoon force extended out 65 miles (105 km) from the center of Koguma’s circulation. Winds to tropical storm force extended out 150 miles (240 km) from the center of Typhoon Koguma.
The Hurricane Intensity Index (HII) for Typhoon Koguma is 25.1. The Hurricane Size Index (HSI) is 19.9 and the Hurricane Wind Intensity Size Index (HWISI) is 45.0. Typhoon Koguma is similar in intensity in intensity to Hurricane Harvey when Harvey hit Texas in 2017. Koguma is larger than Harvey was.
Typhoon Koguma will move into an environment that will become unfavorable for intensification during the next 24 hours. Koguma will move over water where the Sea Surface Temperatures are near 28°C. It will move under the upper level western winds in the middle latitudes. The vertical wind shear will increase when Koguma moves under those upper level westerly winds. Typhoon Koguma will start to weaken when the vertical wind shear increases.
Typhoon Koguma will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Koguma toward the north during the next 24 hours. On its anticipated track, Typhoon Koguma willmove away from Iwo To on Sunday.







