Yun-yeung’s initial forecast track takes the 12th numbered storm of the season more than 140 miles southeast of Yokosuka Naval Base at mid-evening Friday as a tropical storm. (Joint Typhoon Warning Center)

Midnight Tuesday, Sept. 5, Japan time: Tropical Depression Yun-yeung has spawned Tuesday evening more than 900 miles southwest of the Tokyo area.

Joint Typhoon Warning Center’s initial forecast track takes the 12th numbered storm of the season more than 140 miles southeast of the Kanto Plain at mid-evening Friday as a middling tropical storm.

At 9 p.m., Yun-yeung was 961 miles south-southwest of Yokosuka Naval Base, moving northeast at 9 mph with 29-mph sustained winds and 40-mph gusts. U.S. bases in Japan remain in seasonal Tropical Cyclone Conditions of Readiness.

JTWC projects Yun-yeung to keep moving northwest, peak at 63-mph sustained winds and 81-mph gusts at mid-evening Thursday, then weaken to 52-mph sustained winds and 63-mph gusts as it rumbles 143 miles southeast of Yokosuka at 9 p.m. Friday.