Still moving slowly south of Japan, wayward Tropical Storm Wukong shifted course from northeast to northwest Tuesday afternoon, on track for landfall late Saturday over southwestern Kyushu Island, threatening both Iwakuni Marine Corps Air Station and Sasebo Naval Base.

Meanwhile, further south, Tropical Storm Sonamu began weakening, with forecasts calling for it to become a tropical depression sometime Wednesday northwest of Iwo Jima.

Wukong, the 11th storm of the northwest Pacific’s tropical cyclone season, has followed a zigzag northward course, at first tracking northwest on Sunday, then northeast overnight Monday and Tuesday before veering back to the north-northwest Tuesday afternoon.

“It’s kind of going its own track for right now,” said Iwakuni weather chief Gunnery Sgt. Christopher Geraci. He cited “very weak mid-level steering flow” as the reason for Wukong’s wobbly path.

Iwakuni remained in Tropical Cyclone Condition of Readiness 3 “for the time being,” Geraci said. Sasebo remained in TCCOR Storm Watch, according to base spokesman Chuck Howard. Though Wukong was forecast to be four days from landfall, Sasebo officials said plans are in place to move ships out of danger or into anchorage and dry dock should Wukong pose a threat to the naval base.

“There’s still time to execute that,” Howard said. “You never can tell with the fickle nature of weather. We’ll watch the forecasts and react accordingly.”

Not immediately known Tuesday was what plans Iwakuni officials had to evacuate aircraft in advance of the storm.

At midnight Tuesday, Wukong churned 529 miles east-southeast of Sasebo and 500 miles southeast of Iwakuni. Its forward speed increased from 4½ mph at noon to 9 mph at 6 p.m. The storm was packing sustained winds of 52 mph and gusts of up to 63 mph.

The Joint Typhoon Warning Center forecast that Wukong would strengthen into a typhoon overnight Wednesday into Thursday morning as it rumbled toward Kyushu, making landfall at 9 p.m. Friday near the coastal city of Oita and packing sustained 75 mph winds and 92 mph gusts as it slams ashore.

Closest point of approach for Sasebo is 52 miles east at 2 a.m. Sunday and 92 miles west of Iwakuni at 1 p.m. Saturday. Winds will have diminished to 52 mph sustained and 63 mph gusts at its center.

Wukong will then move into the Tsushima Strait between Kyushu and South Korea, with sustained 40 mph winds and 52 mph gusts as it grazes Chinhae Naval Base some 58 miles north at 9 p.m. Sunday.

Steadily weakening Sonamu kept swirling away from Okinawa, northeast toward Iwo Jima. The JTWC forecasts it to curve north and northwest and gradually dissipate into a tropical depression by Wednesday. At midnight Tuesday, Sonamu was 150 miles west-southwest of Iwo Jima, streaking northeast at 26½ mph with sustained winds of 40 mph and 52-mph gusts.

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