Tropical Storm Humberto becomes a hurricane, NHC says

Tropical Storm Humberto has strengthened into a hurricane over the Atlantic and is forecast to intensify further, with the US National Hurricane Center expecting it to become a major hurricane this weekend, the agency said on Friday.

Hurricane Humberto is about 465 miles (750 km) northeast of the northern leeward islands packing maximum sustained winds of 75 mph (120 km/h), the NHC added in its latest advisory.

According to USA Today, while Hurricane Humberto continues to strengthen over the Atlantic and is forecast to become a major hurricane with wind speeds of 130 mph, it is not the storm posing the greatest threat to the US.

The system that Americans need to watch most closely is not yet named, but is expected to develop into Tropical Storm Imelda in the coming days. Although Humberto is forecast to remain out at sea, it could still influence Imelda’s path through a meteorological process known as the Fujiwhara effect.

“How the storms interact with one another and with other weather systems in the region will determine the extent of impacts the storms could have on the US East Coast, the Bahamas and potentially Bermuda over the next few days,” National Hurricane Center director Michael Brennan said on the evening of 25 September. “But the risks are growing for impacts along the coast between Florida and North Carolina.”

In Charleston, South Carolina, National Weather Service meteorologist Blair Holloway said on the morning of 26 September that confidence in the forecasts for Imelda “has not increased or changed much from yesterday (Sept. 25).” “Considerable uncertainty remains including its development, track, intensity, timing, and potential impacts,” Holloway added.

Houston-based meteorologist Matt Lanza, writing on his Substack The Eyewall, said a majority of models predict the system could move toward the Carolinas by Tuesday. “However a non-trivial number of models peel the system back to the east, into the open Atlantic, due in part to some complex interactions with Hurricane Humberto.”

Heavy rain may become Imelda’s main impact. “There is real potential here for a rainmaker in the Carolinas, and particularly North Carolina,” Lanza said. “Readers there will certainly and understandably be concerned that this could become another Hurricane Helene-like event. For now, we think that is unlikely, as the strongest rains appear to be east of areas most impacted by Helene, and the overall signal for prolonged, heavy rainfall is lower this time.”

Currently, NOAA predicts 6 to 10 inches of rainfall for the hardest-hit areas. For now, Humberto is expected to follow a pattern similar to Hurricane Erin, moving between the US and Bermuda.

However, its strengthening increases the risk of long-period swells, creating hazardous seas and surf along the US coast. Its exact track remains uncertain and is tied to the future of Imelda and other weather systems in the region.

Humberto is forecast to reach major hurricane status with wind speeds of 145 mph by 28 September, roughly 1,100 miles east-southeast of Miami. Phil Klotzbach, hurricane researcher at Colorado State University, said the Atlantic would then be “3 for 3” in hurricanes reaching major status this year, following Erin and Gabrielle.