What Is The Fujiwhara Effect & Will It Affect Hurricane Dorian’s Path?

hurricane dorian shot by a naval satellite
United States Naval Research Laboratory / Wikimedia Commons (GPL Cropped, resized.)

Hurricane Dorian is currently churning in the Atlantic Ocean, having been officially upgraded from a tropical storm to a hurricane as of 2:00 p.m. Eastern Time Wednesday. Making matters worse, the storm may be subject to what is known as the Fujiwhara Effect, a weather phenomenon that could make the hurricane significantly worse than previously feared.

What Is The Fujiwhara Effect?

Named for Japanese meteorologist Sakuhei Fujiwhara, the phenomenon occurs when two hurricanes occurring close together spin around each other and, in some cases, form into one mega-hurricane.

As The National Oceanic and Atmospheric Administration (NOAA) explains, sometimes two hurricanes within a few hundred miles of each other will begin a sort of “dance” where they spin around a common center. In some cases, a smaller one will eventually be absorbed into a bigger one. In other cases, they’ll orbit around each other before eventually splitting off into different directions.

And in rare cases, two hurricanes of similar size will merge into one mega-storm. In other cases, the storms may tear each other apart.

It happened in 2017. As USA Today reported at the time, over in the Eastern Pacific, Hurricanes Hilary and Irwin were locked in a “dance of death” off of Mexico’s western coast. Fortunately, as the National Hurricane Center later reported, wind shear from Hilary weakened Irwin, and it was eventually downgraded to a remnant before it made landfall.

What Does This Mean For Hurricane Dorian?

As of this writing, it doesn’t appear as if the Fujiwhara Effect will come into play with regard to Dorian. There is another tropical storm brewing out in the Atlantic, a disturbance that, if it coalesces and gains strength, will be named Tropical Storm (and, later, Hurricane) Erin. According to NOAA, that storm is currently brewing over the Bahamas. However, the storm is hundreds of miles away from Dorian, and as of this writing, has a less than 20 percent chance of forming into a tropical storm over the next five days. By that time, Dorian should have already made landfall.

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Future Hurricanes And The Fujiwhara Effect

Though considered something of a rarity now, hurricanes strengthened by the Fujiwhara Effect could become more commonplace in the future, Business Insider reports, due to climate change.

Dorian’s Expected Path

Meanwhile, Dorian is expected to strengthen into a Category 2 hurricane over Labor Day weekend, CNN reports, with a projected landfall over Florida’s east coast and parts of the Georgia coastline. It is expected to make landfall by Sunday night or Monday morning.