BEIJING, Aug. 21 (Xinhua) -- China's national observatory continued to issue a blue alert Tuesday morning for Typhoon Soulik, the region's 19th typhoon this year.

The tropical cyclone will enter the East China Sea Tuesday evening and then move northwestward in the next three days until landing in the Korean Peninsula on Friday, where it will start to weaken, the National Meteorological Center (NMC) said in a statement.

The NMC warned of gales on affected waters and said they were still uncertain about Soulik's path on land, suggesting local governments prepare for possible disasters and ships in affected areas return to port.

At 8 a.m. Tuesday, the eye of Soulik was above the northwestern Pacific Ocean, 610 km southeast of Japan's Kyushu island, packing winds up to 48 meters per second. The NMC said that Soulik would move northwestward at a speed of 25 km per hour and intensify in the process.

China has a four-tier color-coded weather warning system for typhoons with red representing the most severe, followed by orange, yellow, and blue.