This week, four tropical systems located in the western and eastern Pacific, will encounter the Fujiwhara effect. The Fujiwhara effect Is named after a Japanese researcher, Dr. Fujiwhara, after he performed various experiments on water vortices in the 1920’s. He concluded that when two cyclones come within 900 miles of each other, they will occasionally rotate cyclonically (counter-clockwise) around one another. As they rotate around, the two cyclones will sometimes have a tendency to merge together. The process will end when: “there is a stronger influence of a large-scale weather system from outside, one of the tropical cyclones weakens or the two cyclones merge” (Hong Kong Observatory).
In the eastern Pacific, Hurricane Hilary and Tropical Storm Irwin will begin to rotate around one another. Since Hilary is the larger storm, Irwin will be absorbed by Hilary after encountering the Fujiwhara effect. Southern California will feel some effects as the two systems will bring high surf and rip currents to the coast. In the western Pacific, Typhoon Noru and Tropical Storm Kulap will also experience the Fujiwhara effect. In this case, Typhoon Noru is the larger storm and Tropical Storm Kulap will be absorbed. While the event in the western Pacific doesn’t pose any threat to land, forecasters cannot rule out a possible land impact to the Japanese coast.
The Fujiwhara effect is not rare, however, it is rare for two events within the same week to happen.
Stay tuned for more in the tropics here!
ⓒ 2017 Meteorologist Brandie Cantrell