Former Tropical Storm Nyatoh strengthened to a typhoon west of the Marianas on Wednesday. At 10:00 a.m. EST on Wednesday the center of Typhoon Nyatoh was located at latitude 15.5°N and longitude 135.6°E which put it about 580 miles (935 km) west-northwest of Guam. Nyatoh was moving toward the north-northwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 981 mb.
Former Tropical Storm Nyatoh continued to strengthen over the Western North Pacific Ocean west of the Marianas on Wednesday. The inner end of a rainband wrapped around the center of Typhoon Nyatoh and microwaves satellite images indicated that an eye was forming. The developing eye was surrounded by a broken 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 Nyatoh. Storms near the core generated upper level divergence that pumped mass away from the typhoon. Winds to typhoon force extended out 35 miles (55 km) from the center of Nyatoh. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.
Typhoon Nyatoh will move through an environment mostly favorable for intensification during the next 24 hours. Nyatoh will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of the axis of an upper level ridge centered near the Marianas. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Clockwise flow around a high pressure system centered over eastern Asia will transport drier air toward the northwestern part of Nyatoh’s circulation. The drier air is likely to remain northwest of Typhoon Nyatoh during the next 24 hours. Nyatoh could intensify more rapidly once the eye and eyewall become fully formed. Typhoon Nyatoh will continue to strengthen and it could intensify to the equivalent of a major hurricane during the next 24 hours. An upper level trough west of Japan will produce southwesterly winds that will begin to affect Nyatoh later this week. Those winds will create more vertical wind shear and the shear will cause Typhoon Nyatoh to weaken.
Typhoon Nyatoh will move around the western part of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Nyatoh toward the north during the next 24 hours. The upper level trough will steer Typhoon Nyatoh toward the northeast after Nyatoh moves around the western end of the high pressure system. On its anticipated track Tropical Storm Nyatoh will remain west of the Marianas during the next 24 hours. Nyatoh could approach Iwo To in 48 hours.