Two Hurricanes Walk into a Bar..

August 22, 2020

Must be 2020.
Actually, the situation is not that rare, and has a name.
According to Jeff Berardelli, below, it’s never happened in the Gulf of Mexico…

Houston Chronicle:

If the two storms headed toward the Gulf of Mexico track closely enough, it could set off a rare moment involving an “intense dance around their common center.”

A National Weather Service post described the phenomenon — known as the Fujiwhara Effect — in those terms after two instances in 2017.

“Their circulations sort of detect each other,” said Lance Wood, a meteorologist with the National Weather Service’s Houston/Galveston office, “and they can start to move around a common point between them.”

Forecasters are keeping an eye on this as Tropical Depression 14 (expected to be named Marco once it strengthens) and Tropical Storm Laura head toward the Gulf of Mexico. As of Friday, Laura was expected to move toward Florida and the northeastern Gulf, while Tropical Depression 14 was headed toward the coast of Texas and/or Louisiana. Both are expected to be in the Gulf of Mexico early next week.

The Fujiwhara Effect is a possibility, Wood said, but it also may not happen. It’s too soon to know.

USAToday:

When two hurricanes spinning in the same direction pass close enough to each other, they begin an intense dance around their common center, the National Weather Service said. 

The effect is thought to occur when storms get about 900 miles apart. 

Storms involved in the Fujiwhara effect are rotating around one another as if they had locked arms and were square dancing. Rather than each storm spinning about the other, they are actually moving about a central point between them, as if both were tied to the same post and each swung around it separately of the other.

A good way to picture this is to think of two ice skaters who skate quickly toward each other, nearly on a collision course, grab hands as they are about to pass and spin vigorously around in one big circle with their joined hands at the center.

The effect is named after Dr. Sakuhei Fujiwhara who was the chief of the Central Meteorological Bureau in Tokyo shortly after the first World War. In 1921, he wrote a paper describing the motions of “vortices” in water. Water vortices, such as whirlpools, are little water whirls that spin around.

Yet, the Gulf of Mexico has its limitations when two storms vie for dominance.

Some experts said Friday that the watery crater created by plate tectonics (the Gulf) is too small for the legendary Fujiwhara effect.

Instead, one storm typically dominates another in such a confined space, either pushing it away or tearing it apart with tendrils of cirrus clouds marking its own cyclone-toppling wind shear.

4 Responses to “Two Hurricanes Walk into a Bar..”

  1. dumboldguy Says:

    You could also compare the effect to a gigantic rotary lawnmower?

    And the title of this post made me actually laugh (doesn’t happen that often lately). Good job, Greenman.

  2. indy222 Says:

    The real question is – what does this effect do to the max wind speeds?

    • dumboldguy Says:

      If you watch the videos, the answer seems to be that the result will be a bigger storm but not necessarily a stronger one. In the last video, he talks about them twirling around each other and one “slingshotting” off to the east and hitting FL or off to the west and making a more direct hit on TX.


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