North Pacific Ocean is experiencing a very rare and unusual phenomenon. Eight Tropical Cyclones are spinning at the same time, something that hasn’t been seen in more than four decades. This exceptional event occurred on July 22.
Initially, there were two named storms in the Central and eastern Pacific Ocean, Fernanda and Greg. They’re later joined by Tropical Depression Nine-E and Tropical Depression Ten-E. This two eventually went on to become Tropical Storm Hilary and Irwin.
It’s not rare that Multiple Tropical Cyclones are forming at the same time. But eight Tropical Storms at the same time is quite exceptional. It was last Happened in 1974, according to Dr. Phil Klotzbach, a tropical scientist at Colorado State University.
Although, Most of these eight tropical Cyclones observed will not affect land directly. Only two will make an impact on the land. One is Roke, which brought heavy rain in parts of China and Sonca, Which will drench China’s Hainan Island.
What’s happening there?
Eastern North Pacific Ocean has been active throughout July. But Western Pacific typhoon season made a delayed start. It finally saw a boost in activity during recent days. It’s one of the main factors that helped play a key role in this rare Tropical Cyclone activity.
Weather Channel Explained, “Areas near the equator don’t get cold fronts. The only changeable weather over a relatively short period of time is a roughly 30-60 day wet/dry cycle triggered known as the Madden-Julian Oscillation. The MJO is essentially a wave of energy in the atmosphere that propagates eastward around the Earth near the equator once every 30-60 days.”
By ‘wave’, it means the MJO has a stage where upward motion in the atmosphere is strong, which is helping to boost the formation of cloud and thundershowers.
Rare Fujiwhara effect
Western Pacific Ocean also saw another rare event at the same time, which is being called the Fujiwhara effect. It was named after a Japanese researcher in the early 1920’s. This effect explains how two tropical cyclones 800 to 900 miles apart rotate counter clockwise about one another. Think of the teacup ride at Disney or the Tilt-a-Whirl at your local county fair, but with tropical systems instead.
There are currently such two active tropical cyclones well east of Japan. The westernmost one is named ‘Noru’ and the other is ‘Kulap’, located about 1,000 miles to the east-northeast of Noru.