Typhoon Nyatoh strengthened to the equivalent of a major hurricane over the Western North Pacific Ocean southwest of Iwo To on Thursday. At 10:00 a.m. EST on Thursday the center of Typhoon Nyatoh was located at latitude 18.7°N and longitude 137.1°E which put it about 540 miles (875 km) southwest of Iwo To. Nyatoh was moving toward the northeast at 15 m.p.h. (24 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 955 mb.

Typhoon Nyatoh rapidly intensified to the equivalent of a major hurricane on Thursday. A circular eye with a diameter of 35 miles (55 km) formed at the center of Nyatoh. 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 Nyatoh. Storms near the core generated strong upper level divergence that pumped mass away to the northeast of the typhoon.

The circulation around Typhoon Nyatoh increased in size on Thursday. Winds to typhoon force extended out 65 miles (105 km) from the center of Nyatoh. Winds to tropical storm force extended out 220 miles (355 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Nyatoh was 20.6. The Hurricane Size Index (HSI) was 22.1 and the Hurricane Wind Intensity Size Index (HWISI) was 42.7.

Typhoon Nyatoh will move through an environment that will become unfavorable for intensification during the next 24 hours. Nyatoh will move over water where the Sea Surface Temperatures are near 28˚C. An upper level trough near Japan will produce southwesterly winds that will blow toward the top of Nyatoh’s circulation. Those winds will cause the vertical wind shear to increase during the next 24 hours. Clockwise flow around a surface high pressure system centered over eastern Asia will transport drier air toward the northwestern part of Nyatoh’s circulation. The drier air will begin to be pulled into the northwestern part of Typhoon Nyatoh’s circulation during the next 24 hours. The combination of more vertical wind shear and drier air will cause Typhoon Nyatoh to start to weaken.

The upper level trough near Japan will steer Typhoon Nyatoh toward the northeast during the next 24 hours. On its anticipated track Typhoon Nyatoh could approach Iwo To on Friday. Although Nyatoh will weaken, it will bring strong winds and locally heavy rain to Iwo To.