Forecasters have their hands full as two tropical systems form in the Atlantic. Their complex interaction will determine if and when the East Coast receives any impacts.
Within the past week, worldwide tropical cyclone activity has surged. Two super typhoons in the Pacific, Ragasa and Neoguri, and major Hurricane Gabrielle, all whipped up powerful, violent winds in the span of just three days.
Ragasa’s wind gusts peaked at 200 mph on Sunday, Neoguri’s winds reached 175 mph the day before, and Gabrielle’s winds climbed to 140 mph on Monday. By Wednesday, the National Hurricane Center was tracking Tropical Storm Humberto and another potential developing tropical cyclone in the southern Atlantic.
Humberto has since strengthened to a hurricane, per the NHC, and its location relative to a disturbance that could develop into Tropical Storm Imelda could lead to these dueling tropical systems interacting, influencing the development and path of each.
The complex interaction between two tropical cyclones that come in close proximity to each other can be governed by something called the “Fujiwhara effect,” named after Japanese meteorologist Sakuhei Fujiwhara — whose name would have been spelled as “Fujiwara” were it Romanized today — after he was the first to professionally describe the complicated phenomenon in 1921.
It will make the forecast for both storms challenging. “Here’s how it works,” Jeff Berardelli, WFLA Chief Meteorologist and Climate Specialist, posted on X. “Between the 2 storms is a pivot point (sort of like a fulcrum on a seesaw), it happens to be near where the sinking/ driest air is. If conditions are right we may see them pivot, or if one’s stronger (Bermuda hurricane) its force will sling shot the weaker one around it.”
Hurricanes that approach each other can engage in an intricate “dance.” If one storm is much stronger, the smaller hurricane often revolves around it before being pulled in. When storms are closer in strength, they may merge, or they can temporarily rotate around each other before eventually being shot off on their own separate paths. In rare cases, their interaction produces a single, larger hurricane.
Humberto is strengthening fast, and forecasters with the NHC think it will soon undergo rapid intensification, which the National Weather Service defines as “an increase in the maximum sustained winds of a tropical cyclone of at least 30 kt in a 24-h period.”
“Humberto continues to rapidly strengthen this morning,” according to Friday morning’s NHC forecast discussion. “Infrared satellite images show a ring of deep, cold inner core convection wrapping around an eye that has recently emerged in conventional satellite imagery. The rapidly improving satellite structure, along with conducive environmental and oceanic conditions, suggest that significant to rapid intensification (RI) is likely to continue in the short term.”
Hurricane Humberto was packing maximum sustained winds of 90 mph and was located around 450 miles northeast of the northern Leeward Islands on Friday. The disturbance being monitored by the NHC that could interact with Humberto was located near Hispaniola. The NHC is giving it a 90% chance of becoming a tropical cyclone in the next seven days.
People living along the East Coast, in particular the Carolinas and Mid-Atlantic region, need to keep a close eye on how these two systems will behave over the weekend. Some computer models are suggesting impacts for the Carolinas could come early next week.
This scenario will undoubtedly stir up anxiety among those who endured Hurricane Helene last fall. This weekend marks the one-year anniversary of when Helene caused devastating flooding in North Carolina. The storm was another example of how our warming world can supercharge extreme weather events.
Researchers with World Weather Attribution found that our warming world was “a key driver of catastrophic impacts of Hurricane Helene that devastated both coastal and inland communities.”
Killing at least 250 people, Helene was the deadliest continental U.S. hurricane since Katrina and the seventh costliest hurricane on record, according to an NHC summary on the storm.
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