Sempaka is not expected to intensify as it is closer to the ground. According to the Hong Kong Observatory’s Typhoon Warning Signals, a strong wind signal number 3 was in effect for Hong Kong, indicating wind speeds of 41 to 62 kph (about 25–40 mph).
The other storm, In-fa, is moving north, mainly affecting the southern islands of Japan and Taiwan. It is forecast to strengthen into a hurricane Tuesday night, but it is not likely to interact with Sempaka.
In-fa is expected to rain in Japan ahead of the Olympic Games starting on Friday in Tokyo. Hurricanes can be a boon for surfers training for the inaugural Olympic surfing competition.
Sempaka is expected to make landfall on Tuesday afternoon or evening near the city of Yangjiang in China’s Guangdong province, causing heavy, flooding rains to lash the country’s southeastern parts for much of this week.
Widespread rainfall is estimated to be 100 to 200 millimeters (about 4 to 8 inches) in Guangdong, Guangxi and Hainan provinces. As of Friday local time, isolated locations can reach up to 500 millimeters (about 20 inches). Strong, gusty winds will also occur, particularly near the coast where the storm will make landfall, causing isolated power outages.
The Joint Typhoon Warning Center said it expects Sempaka to pass over these provinces and possibly return to the South China Sea by the end of this week, increasing the risk of rain and flooding, especially near the coast.
Powerful typhoons are a regular occurrence during the summer in southern China, although they can form throughout the year due to the warm waters of the Pacific. Therefore, unlike the Atlantic hurricane season, the beginning and end of the western Pacific hurricane season are not defined.