In its latest warning, the National Hurricane Center said Debbie was a tropical storm that formed over North Carolina on Thursday afternoon Eastern time.
The tropical depression had sustained sustained winds of 35 mph, and excessive rainfall was expected to pose the greatest threat as the storm moved inland.
As Debby moves at a walking pace across the Southeast this week, it could dump 10 to 20 or more inches of rain, with some areas potentially reaching 30 inches.
Storm surges, when seawater is forced onto land by storm winds, have historically been a major cause of deaths from hurricanes, and when they occur during high tide they can have far-reaching effects.
Location: Charleston, SCDeBordieu, SCSavannah, GA.
Potential for flooding due to storm surge
Debbie’s predicted path
All times on the map are Eastern Time. From The New York Times
What does a storm look like from above?
Satellite imagery helps determine the strength, scale and cohesion of a storm.
Debbie is the fourth named storm to form in the Atlantic in 2024.
The National Oceanic and Atmospheric Administration predicted in late May that this year would be above average, with 17 to 25 named storms.
This season follows a very active year with 20 named storms recorded, including an earlier storm that was later given the official name “No Name.” It is the eighth consecutive year with more than 14 named storms. Only one hurricane, Idalia, made landfall in the United States.
Last season’s El Niño weather pattern would normally have suppressed hurricanes and reduced the number of storms this season, but in 2023, warmer waters in the Atlantic Ocean slowed El Niño’s usual effect of blocking storms.
The warm ocean temperatures that drove last year’s season have gotten even warmer early this season, making forecasters more confident that there will be more storms this year. Warmer seas could also cause storms to intensify more quickly than usual.
To make matters worse, last year’s El Niño weather phenomenon is also weakening, likely creating an even more favorable environment for storms to form and intensify.
Hurricanes need calm conditions to develop, and a strong El Niño in the Atlantic increases wind shear — the change in wind speed and direction with height — which inhibits the ability of storms to merge. The absence of an El Niño this year increases the chances that clouds will tower high enough to sustain powerful cyclones.
Sources and Notes
Tracking Map Source: National Hurricane Center | Notes: Maps show at least a 5 percent probability. Forecasts are up to 5 days out and up to 3 hours before the storm’s reported latest location. Wind speed probability data is not available north of 60.25 degrees north latitude.
Wind Arrival Table Source: New York Times analysis of National Hurricane Center data (arrival time), U.S. Census Bureau and Natural Earth (geographic location), Google (time zones) | Note: This table shows the projected arrival times for certain cities that could be affected by sustained destructive winds of 58 mph or greater. If destructive winds reach a particular location, there is less than a 10 percent chance that they will arrive before the “earliest reasonable” time, and a 50 percent chance that they will arrive before the “most likely” time.
Radar Maps Source: National Oceanic and Atmospheric Administration (via Iowa State University) | Note: These mosaics are generated by combining over 130 individual RADARs that make up the NEXRAD network.
Storm Surge Map Source: National Hurricane Center | Note: Forecast includes only the U.S. Gulf Coast, Atlantic Coast, Puerto Rico, and the U.S. Virgin Islands. Actual areas that may be flooded may differ from those shown on this map. This map takes into account tides, but not flooding caused by waves or rainfall. This map also includes intertidal areas that are regularly flooded during normal high tides.
Satellite Map Source: National Oceanic and Atmospheric Administration | Note: Imagery is updated only between sunrise and sunset for the latest storm locations.