Humberto is a powerful Category 4 hurricane in the Atlantic Saturday, Sept. 27, but the system of most concern for U.S. East Coast residents is a storm near the Bahamas expected to become Tropical Storm Imelda this weekend, according to the latest advisory from the National Hurricane Center.
At 8 a.m., the storm designated as Potential Tropical Cyclone 9 was 110 miles south of the central Bahamas with 35 mph winds.
The storm is expected to become Tropical Storm Imelda in the next 24 hours and produce significant rainfall over portions of eastern Cuba and the Bahamas.
The system is expected to move across the central and northwestern Bahamas this weekend before becoming a hurricane by late Monday and approaching the southeast U.S. coast early next week.
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Tropical storm warnings are in effect for portions of the central and southwestern Bahamas.
While Humberto is expected to remain out at sea, it could affect the path and intensity of would-be Imelda, making the impact on the U.S. difficult to predict. The two could interact with each other in known as the Fujiwhara effect.
While there is still some uncertainty in the long-range track of the system and even if interaction with Humberto keeps it offshore, forecasters say there is an increasing threat of heavy rainfall early next week from coastal Georgia through the Carolinas and into the southern Mid-Atlantic states, which could cause flash, urban, and river flooding as as well as heavy rainfall/flooding concerns in inland areas.
South Carolina Gov. Henry McMaster declared a statewide state of emergency Friday.
“As this storm approaches our coast, I am issuing a State of Emergency to ensure Team South Carolina is able to access and deploy the resources and personnel needed to prepare for and respond to this storm,” McMaster said. “While the storm’s arrival, speed, and intensity remain hard to predict, we do know that it will bring significant wind, heavy rainfall, and flooding across the ENTIRE state of South Carolina. We have seen this before. Now is the time to start paying attention to forecasts, updates, and alerts from official sources and begin making preparations.”
Where is Hurricane Humberto?
Special note on the NHC cone: The forecast track shows the most likely path of the center of the storm. It does not illustrate the full width of the storm or its impacts, and the center of the storm is likely to travel outside the cone up to 33% of the time.
Spaghetti models for Hurricane Humberto
Special note about spaghetti models: Spaghetti model illustrations include an array of forecast tools and models, and not all are created equal. The Hurricane Center uses only the top four or five highest performing models to help make its forecasts.
Where is Potential Tropical Cyclone 9, future Tropical Storm Imelda?
Potential Tropical Cyclone 9 is forecast to become Tropical Storm Imelda this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings are in effect.
A north-northwestward motion is expected to begin later today and continue through Monday.
On the forecast track, the center of the system is expected to move across the central and northwestern Bahamas this weekend and approach the southeast U.S. coast early next week.
Rainfall associated with this system is expected to impact eastern Cuba, Hispaniola, Jamaica, and the Bahamas through the weekend, which will likely produce flash and urban flooding. Mudslides are possible in the higher terrain.
There is an increasing threat of heavy rainfall early next week from coastal Georgia through the Carolinas and into the southern Mid-Atlantic states, which could cause flash, urban, and river flooding.
While there remains considerable uncertainty in the long-range track and intensity of the system, there is an increasing threat of heavy rainfall early next week from coastal Georgia through the Carolinas and into the southern Mid-Atlantic states, which could cause flash, urban, and river flooding., the Hurricane Center said.
A tropical storm warning is in effect for:
Central Bahamas, including Cat Island, the Exumas, Long Island, Rum Cay, and San Salvador
Portions of the northwestern Bahamas, including Eleuthera, New Providence, the Abacos, Berry Islands, Andros island, and Grand Bahama Island
Key messages for Potential Tropical Cyclone 9, soon to be Imelda
The disturbance is forecast to become a tropical storm this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings are in effect.
The disturbance is forecast to become a tropical storm this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings are in effect.
The disturbance is forecast to become a tropical storm this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings are in effect.
The disturbance is forecast to become a tropical storm this weekend and bring tropical storm conditions to portions of the central and northwestern Bahamas, where Tropical Storm Warnings are in effect.
Spaghetti models for PTC 9, future Imelda
Special note about spaghetti models: Spaghetti model illustrations include an array of forecast tools and models, and not all are created equal. The Hurricane Center uses only the top four or five highest performing models to help make its forecasts.
Will future Tropical Storm Imelda impact South Carolina?
The storm is expected to track north-northwest across the Bahamas and parallel to the east coast of Florida.
While no direct impact is expected, dangerous beach and boating conditions are forecast to develop late Sunday into next week, the National Weather Servicen Jacksonville reported.
Localized flash flooding is possible along and east of the I-95 corridor.
The system is expected to bring heavy rain, high winds and dangerous surf along the East Coast.
“There is an increasing threat of heavy rainfall early next week from coastal Georgia through the Carolinas and into the southern Mid-Atlantic states, which could cause flash, urban, and river flooding,” according to the National Hurricane Center.
Residents should continue to monitor the forecast for updates and ensure their emergency plan is ready.
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“At this time, we are thinking that the storm should remain off the east coast of Florida, regardless of the scenario with Humberto,” said AccuWeather lead hurricane expert Alex DaSilva at 8 a.m. Sept. 26.
“So, right at this point, we do not expect a direct landfall to Florida, although it’s possible that this could get pretty close. Florida still needs to pay close attention.”
Once the invest develops a defined area of circulation, forecasters will have a better idea of what will happen.
“Regardless of whether a hurricane makes landfall in the southeastern U.S. or not, strong winds will create large, chaotic swells that will propagate toward the southern and middle Atlantic coast late this weekend to the middle of next week,” according to AccuWeather.
Be prepared for the possibility of coastal flooding, strong rip currents and beach erosion, AccuWeather forecasters said.
What is the Fujiwhara effect?
“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.
“If one hurricane is a lot stronger than the other, the smaller one will orbit it and eventually come crashing into its vortex to be absorbed.
“Two storms closer in strength can gravitate toward each other until they reach a common point and merge, or merely spin each other around for a while before shooting off on their own paths.
“In rare occasions, the effect is additive when the hurricanes come together, resulting in one larger storm instead of two smaller ones.”
So simply put, if there are two hurricanes spinning close together — usually between 345 and 863 miles — here’s what can happen:
One gets absorbed by the other
They merge into a single storm
They shoot off on their own path in a sort of slingshot effect
Rarely, they not only merge but become a larger storm than each individual was
Memories of Hurricane Helene fresh as eyes keep wary eye on tropics
A combination of weather factors and geography helped make Hurricane Helene one of the most brutal storms in the modern history of hurricanes.
Helene formed in the northwestern Caribbean on Sept. 24, 2024, and rapidly intensified into a powerful Category 4 hurricane before making landfall near Perry, Florida, less than 72 hours later.
➤ Hurricane Helene began a path of destruction a year ago. Why was it was so deadly?
Then a double whammy from a colliding weather pattern set up historic rainfall across the North Carolina and Tennessee mountains.
A year later, many hurricane victims from Florida to Tennessee continue to struggle with attempts to rebuild and recover.
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Brandi D. Addison covers weather across the United States as the Weather Connect Reporter for the USA TODAY Network. She can be reached at baddison@gannett.com.
This article originally appeared on Greenville News: Will Imelda develop? South Carolina to receive heavy rain.