Rare Fujiwhara Effect Steers Tropical Storm Imelda Away from US

As of September 29th, 2025, a rare meteorological phenomenon known as the Fujiwhara Effect is playing a crucial role in steering Tropical Storm Imelda away from the United States. The interaction between Imelda and the powerful Hurricane Humberto, tracking west of Bermuda, has caused the storm to take a sharp turn out to sea, avoiding a potentially devastating landfall.

Initially, Imelda was forecast to track inland over the Southeastern states, raising concerns about major flooding in the Carolinas and Georgia. In a worst-case scenario, it could have led to widespread inland and coastal flooding, comparable to the impacts of Hurricane Matthew or Nicole in 2016. However, a high-pressure system building over the Northeast has blocked Imelda's northward path, allowing Humberto to tug at the storm and steer it away from the U.S. coast.

While this is good news for the mainland, the combination of Humberto, Imelda, and the high-pressure system will still have significant impacts. Coastal areas from Florida to the Carolinas, as well as parts of the Mid-Atlantic and Northeast, can expect prolonged rough surf, hazardous rip currents, and minor to moderate coastal flooding in the coming days. Winds will remain stiff out of the northeast, further enhancing tidal surges. Swells generated by the storms will also pose hazards for fishing vessels, cruise ships, and other maritime interests, with wave heights near Humberto's core expected to exceed 40 feet offshore.

In addition, periods of heavy rainfall and scattered thunderstorms, some strong enough to cause localized flash flooding, are likely along portions of the Florida east coast, Georgia, and the Carolinas through midweek. There is also a risk of quick-moving storms capable of producing waterspouts or isolated tornadoes near coastal regions.

Bermuda, on the other hand, faces a more direct threat, as it is expected to experience impacts from both Humberto and Imelda in close succession. The islands will first deal with Humberto’s glancing blow, followed just a day or so later by a potential direct hit from Imelda as a hurricane. Bermuda can expect gusty winds, squally rain, flooding, and rough seas through the week, with impacts lasting multiple days—posing serious challenges to small craft, shipping lanes, and cruise activity in the region.

Looking ahead, AccuWeather meteorologists are monitoring the Gulf of Mexico and the western Caribbean, as conditions may become favorable for quick tropical development in the coming weeks. Any such system could pose a threat with very little lead time, especially for the southeastern U.S. coast.