TOKYO - Tropical storm Wukong hung nearly stationary off southwestern Japan on Thursday, threatening prolonged heavy rains and landfall overnight.

Wukong -- meaning Monkey King, a legendary Chinese hero -- was 130 km (81 miles) southeast of Miyazaki at 2:45 p.m. (0545 GMT), nearly unchanged from its morning position.

It had slowed slightly and was heading west at 15 km an hour, the Japanese Meteorological Agency said, warning that its slowness meant heavy rains would linger in one area for a long time, increasing the chance of flooding.

The storm maintained winds of up to 83 km (52 miles) an hour at its center and was expected to bring up to 300 mm (12 inches) of rain to some parts of Kyushu, Japan's southernmost main island, by Friday morning.

Landfall on southern Kyushu was likely on Thursday night or possibly early on Friday, a Meteorological Agency official said, but added that the storm appeared to be shifting direction.

"The storm is likely to head in a more northern direction than previously expected, but its movements are extremely difficult to predict right now so almost anything is possible," he said.

The northerly shift means the storm is now likely to head up the Korean peninsula, according to the Tropical Storm Risk ( Web site, which also predicted it would weaken to a tropical depression on Friday.

The Web site had earlier shown the storm heading toward the eastern Chinese provinces of Shandong and Jiangsu.