Former Typhoon Ewiniar weakened to a tropical storm south of Japan on Wednesday. At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Ewiniar was located at latitude 26.9°N and longitude 133.5°E which put it about 120 miles (195 km) northeast of Minamidaitojima, Japan. Ewiniar was moving toward the northeast at 18 m.p.h. (30 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 981 mb.

After bringing strong winds and heavy rain to Minamidaitojima, former Typhoon Ewiniar weakened to a tropical storm on Wednesday. An upper level trough northwest of Japan was producing strong southwesterly winds that were blowing toward the top of Ewiniar’s circulation. Those winds were causing strong vertical wind shear. The wind shear caused former Typhoon Ewiniar to weaken.

The strong vertical wind shear was also affecting the structure of Tropical Storm Ewiniar. The strong upper level southwesterly winds were causing the upper part of Ewinar’s circulation to tilt toward the northeast. Thunderstorms were still occurring in bands in the northern and eastern parts of Tropical Storm Ewiniar. Bands in the southern and western parts of Ewiniar consisted primarily of showers and lower clouds.

The circulation around Typhoon Ewiniar was still small. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

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 25°C. The upper level trough northwest of Japan will continue to cause strong vertical wind shear. The cooler water and strong vertical wind shear will cause Tropical Storm Ewiniar to weaken during the next 24 hours. If the upper level winds get stronger, they could blow the top off of Ewiniar’s circulation. The cooler water and strong vertical wind shear will also cause Tropical Storm Ewiniar to begin to make a transition to an extratropical cyclone.

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.