Humberto, which elevated to a Category 4 hurricane Friday (September 26) morning, could potentially interact with another system to become a rare monster storm, CBS News reports.

Officials at the National Hurricane Center said they were monitoring a second storm near Humberto over the northeastern Caribbean, which would likely be named Imelda as a tropical storm over the weekend. Imelda's system is expected to strengthen in the Bahamas, leading to wind and rainfall striking the coastal parts of the southeastern U.S. and, although considered to be very unlikely, could merge with Humbero to produce what is called the Fujiwhara effect.

The Fujiwhara effect is "an intense dance" between two tropical storms in which they get close enough and either join together or spin around each other before continuing on their separate paths.

"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," said CBS News meteorologist Nikki Nolan.

"Very rarely has a larger system absorbed a smaller one and become larger or stronger, but it is scientifically possible," she added.

Humberto grew into a tropical storm Wednesday (September 24) night while traveling over the Atlantic, becoming the eighth named storm of the current hurricane season, before elevating to a Category 4 hurricane Friday morning. Forecasters expect it to move northwest and strengthen during the coming days, with Imelda present in the same region.

"With the two tropical troubles currently north of the Caribbean, these two may interact under the Fujiwhara effect in the days ahead," Nolan said, but specified that the developing system "appears to be much weaker than Humberto and several miles away from it," and a possible interaction between the two may not result in a tangled gravitational "dance."