Humberto could mingle with Hurricane Imelda in what's called the Fujiwhara effect
The remnants of Hurricane Humberto, the eighth named storm to emerge this hurricane season, is currently swirling in the Atlantic to the north of Hurricane Imelda.
Questions about whether the two storms will collide have circulated since Imelda formed. That's an unlikely outcome, said CBS News meteorologist Nikki Nolan, although it's not impossible. If such a collision does occur, it could produce what's called the Fujiwhara effect, a rare phenomenon in which two tropical storms merge and become entangled around a newly formed, common center.
Humberto affects Imelda
As of Wednesday, the Fujiwhara effect had not technically played out between Humberto and Imelda, which approached Bermuda on Wednesday as a Category 2 hurricane, Nolan said. However, their extraordinarily close proximity for a period of time this week meant that one storm did affect the other.
"Humberto basically lowered the pressure as it moved past Bermuda, which led Imelda to follow in its path, because it's the path of least resistance, essentially," Nolan said.
She noted that Humberto's pull may have helped guide Imelda away from the United States. Officials along the southeastern coast from Florida to the Carolinas have been watching closely to see whether Imelda's path would avoid a direct hit on the mainland.
Nolan said some forecasting models predict that Imelda will end up overtaking Humberto once it passes Bermuda and leaves the tropics.
Fujiwhara effect
How a Fujiwhara effect plays out depends on the characteristics of the storms involved, according to the National Weather Service. The forecasting agency describes the Fujiwhara effect on its website as "an intense dance" between two tropical storms that can happen when they get close enough to each other on their respective tracks to reach a common point and either join together or spin around each other for a period of time before continuing along their individual paths.
In the latter scenario, the storms involved must be comparably strong or large.
"Typically when one system is stronger than the other, the smaller and weaker system will get overrun by the larger, stronger one and completely eliminate it," Nolan said.
Similar systems "will dance around each other" before going their separate ways, she continued, adding: "Very rarely has a larger system absorbed a smaller one and become larger or stronger, but it is scientifically possible."
Humberto grew into a tropical storm last week while traveling over open waters in the central tropical Atlantic. It gained hurricane status early Friday morning and strengthened into a Category 5 on Saturday before weakening again. It has now merged with a front and lost hurricane strength.
Imelda was upgraded from a tropical storm to a hurricane on Tuesday and threatened to bring hurricane conditions to Bermuda by Wednesday evening.
Outside of Bermuda, swells created by both Imelda and Humberto threatened the East Coast of the U.S., with forecasters warning that surf and rip currents could be life-threatening.