The tropical depression had sustained wind speeds of 35 miles per hour. Excessive rainfall was expected to pose the biggest threat as the storm moved inland.
Storm surge is the ocean water pushed ashore by the storm’s winds and has historically been the leading cause of death from hurricanes. If the surge occurs during high tide, it can have far-reaching effects.
Debby is the fourth named storm to form in the Atlantic in 2024.
In late May, the National Oceanic and Atmospheric Administration predicted that there would be 17 to 25 named storms this year, an above-normal amount.
This season follows an overly active year, with 20 named storms — including an early storm later given the official name of “Unnamed.” It was the eighth year in a row to surpass the average of 14 named storms. Only one hurricane, Idalia, made landfall in the United States.
Typically, the El Niño pattern that was in force last season would have suppressed hurricanes and reduced the number of storms in a season. But in 2023, the warm ocean temperatures in the Atlantic blunted El Niño’s usual effect of thwarting storms.
The warm ocean temperatures that fueled last year’s season returned even warmer at the start of this season, raising forecasters’ confidence that there would be more storms this year. The heightened sea surface temperatures could also strengthen storms more rapidly than usual.
To make matters worse, the El Niño pattern present last year is also diminishing, most likely creating a more suitable atmosphere for storms to form and intensify.
Hurricanes need a calm environment to form, and, in the Atlantic, a strong El Niño increases the amount of wind shear — a change in wind speed and/or direction with height — which disrupts a storm's ability to coalesce. Without El Niño this year, clouds are more likely to tower to the tall heights needed to sustain a powerful cyclone.
Sources and notes
Tracking map Source: National Hurricane Center | Notes: The map shows probabilities of at least 5 percent. The forecast is for up to five days, with that time span starting up to three hours before the reported time that the storm reaches its latest location. Wind speed probability data is not available north of 60.25 degrees north latitude.
Wind arrivals table Sources: New York Times analysis of National Hurricane Center data (arrival times); U.S. Census Bureau and Natural Earth (geographic locations); Google (time zones) | Notes: The table shows predicted arrival times of sustained, damaging winds of 58 m.p.h. or more for select cities with a chance of such winds reaching them. If damaging winds reach a location, there is no more than a 10 percent chance that they will arrive before the “earliest reasonable” time and a 50 percent chance they will arrive before the “most likely” time.
Radar map Source: National Oceanic and Atmospheric Administration via Iowa State University | Notes: These mosaics are generated by combining the 130+ individual RADARs that comprise the NEXRAD network.
Storm surge map Source: National Hurricane Center | Notes: Forecasts only include the United States Gulf and Atlantic coasts, Puerto Rico, and the U.S. Virgin Islands. The actual areas that could become flooded may differ from the areas shown on this map. This map accounts for tides, but not waves and not flooding caused by rainfall. The map also includes intertidal areas, which routinely flood during typical high tides.
Satellite map Source: National Oceanic and Atmospheric Administration| Notes: Imagery only updates between sunrise and sunset of the latest storm location.
