Typhoon Toraji - the eighth storm in the South China Sea - is one of four storms that appeared simultaneously in the northwest Pacific and South China Sea in November. The other three are Yinxing, Usagi and Man-yi. This is the first time four storms have appeared in the basin since records began in 28.30.
SCMP interviewed hurricane experts to analyze the reasons for the delay and the possibility of more frequent storms in November.
A reasonable explanation for a late storm like Typhoon Toraji in the East Sea is that sea surface temperatures in the Pacific and East Sea are still warm despite entering November, former assistant director of the Hong Kong Meteorological Station (China) Leung Wing-mo explained.
He pointed out that tropical storms need a minimum sea surface temperature of 26 degrees Celsius to form. It is estimated that the temperature off the coast of the Philippines is currently between 28 and 29 degrees Celsius.
"These seas have stored a huge amount of heat and energy after a long summer. Global warming is also a contributing factor to ocean heat retention," he said.
The typhoon expert of the Hong Kong Meteorological Station (China) added that sea surface temperatures this year and last year have both broken records. Such warm ocean waters are enough to fuel the storm's formation.
The frequency of storms is related to wind currents in the atmosphere. "Storms are like small boats drifting along these wind currents. Those winds can be 1,000 km to 2,000 km in diameter while a typhoon is only a few hundred km in size, said Leung wing-mo.
Meanwhile, Olivia Lee Shuk-ming - senior science officer at the Hong Kong Meteorological Observatory (China) pointed out that this year, the subtropical high pressure band is stronger than usual and further north than usual.
This makes tropical cyclones more likely to appear in the northern latitude of the northwest Pacific than in November of previous years. The storms are about 10 to 15 degrees longitude apart, allowing them to maintain their intensity and continue to strengthen independently, she said.
According to typhoon expert Leung wing-mo, typhoons in November are common. One of the strongest storms ever recorded was Super Typhoon Haiyan, which devastated the Philippines in November 2013.
The Atlantic is also experiencing very warm sea surface temperatures, leading to the formation of many tropical depressions and leading to quite strong storms making landfall in the US.
