Tropical Storm Ewiniar weakened south of Japan on Thursday. At 11:00 a.m. EDT on Thursday the center of Tropical Storm Ewiniar was located at latitude 30.8°N and longitude 137.7°E which put it about 400 miles (645 km) south-southwest of Tokyo, Japan. Ewiniar was moving toward the northeast at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 995 mb.

Strong vertical wind shear and cooler Sea Surface Temperatures caused Tropical Storm Ewiniar to weaken south of Japan on Thursday. No thunderstorms were occurring in Tropical Storm Ewiniar. Bands revolving around the center of Ewiniar’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 90 miles (145 km) from the center of Ewiniar.

Tropical Storm Ewiniar will move through an environment that will be unfavorable for intensification during the next 24 hours. Ewiniar will move over water where the Sea Surface Temperatures are near 24°C. An upper level trough northwest of Japan will produce strong westerly winds that will blow across the top of Ewiniar’s circulation. Those winds will cause strong vertical wind shear. The cooler water and strong vertical wind shear will cause Tropical Storm Ewiniar to continue to weaken during the next 24 hours.

Tropical Storm Ewiniar will move around the northern side of a high pressure system over the Western North Pacific Ocean. The high pressure system and the upper level trough northwest of Japan will steer Ewiniar toward the northeast during the next 24 hours. On its anticipated track, Tropical Storm Ewiniar will remain south of Japan. Ewiniar will pass south of Tokyo in 12 hours.