Hurricane Debbie made landfall near Stanhatchee, Florida at 7 a.m. Monday, August 5, as a Category 1 storm with winds of 80 mph and a central pressure of 979 mb. The storm is expected to bring catastrophic extreme rainfall to coastal areas of Georgia and South Carolina, with 20-30 inches of rainfall possible from the Georgia-South Carolina border to Charleston, South Carolina.
The strongest part of Hurricane Debbie's eyewall passed over Horseshoe Beach Monday morning, where sustained winds reached 68 mph with gusts as high as 98 mph at 5:30 a.m. Within hours, Debbie's winds increased from 45 mph to 80 mph, meeting the minimum definition of rapid intensification: a sustained wind speed increase of 35 mph over a 24-hour period. Debbie made landfall about 10 miles southeast of where Hurricane Idalia made landfall last August 30 as a Category 3 storm with sustained winds of 115 mph.
As of 11 a.m. ET Monday, Debbie had moved about 30 miles inland and had weakened to a tropical storm with winds of 70 mph. Debbie is moving north-northeast at a moderate speed of 8 mph, which is expected to drop to around 4 mph by Tuesday night, allowing the storm to bring catastrophic rainfall to a wide area.
More than 30 centimeters of rain fell in western Florida
Debbie has flooded western Florida: Radar rainfall estimates showed 14 to 18 inches of rain in two counties south of Tampa Bay. Observations from the CoCoRaHS rain gauge network recorded multiple readings exceeding 11 inches in the 24 hours ending at 7 a.m. ET Monday, including a high of 16.04 inches (more than 41 centimeters) in Manatee County. Flooding closed Interstate 75 south of Tampa, and a truck driver was swept off the road and died Monday morning.
Catastrophic extreme rainfall expected in coastal Georgia and South Carolina
Debbie's main damage will be caused by flooding caused by heavy rains. The trough expected to pull Debbie northeastward was not strong enough to do the job, causing the storm to become lodged in an area of weak steering currents off the southeastern coast of the United States for several days. As of Monday morning, the National Hurricane Center forecast 16 to 20 inches (40.6 to 50.8 centimeters) of rain across much of the coastal plain of Georgia and South Carolina, with 20 to 30 inches in areas south of Georgia and the Carolinas. Bordering Charleston, South Carolina. Such rainfall would likely exceed South Carolina's tropical cyclone rainfall record of 23.63 inches (60 centimeters) from Hurricane Florence in 2018.
The National Oceanic and Atmospheric Administration's (NOAA) excess rainfall discussion, conducted at 4:39 a.m. Monday, lists northeastern Florida to southeastern South Carolina as a “high risk” area for heavy rain on Monday, with Georgia and South Carolina expected on Tuesday. High-risk areas will occur across much of the coastal plain. In the United States, only about 4% of days are in high-risk areas, but these areas account for about one-third of all flood deaths and about 80% of flood-related losses. The three-day forecast warns that “multiple widespread flash flooding is possible, with the potential for severe and potentially catastrophic flooding.”
Although much of South Carolina is in a moderate to severe drought, widespread rainfall of more than 10 inches (25.4 cm) will almost certainly cause damaging flooding, especially near the coast, where onshore winds and storm surges will prevent rainwater from draining effectively .
The exact location of Debbie's greatest flood threat is difficult to estimate, as it depends heavily on how long the center remains offshore. With water temperatures off the South Carolina coast of 27-28 degrees Celsius (81-82°F), Debbie will have plenty of thermal energy to re-boost once the center surfaces Tuesday afternoon into Thursday morning. Because the steering currents are weak and the storm is likely to be very close to the coast, slight, unpredictable oscillations in the track will make a huge difference in the amount of rainfall Debbie ultimately dumps. On Monday morning, GFS and European model runs agreed that Debbie's flooding of the southeastern U.S. would eventually end by Friday, when the storm is expected to be trapped by a trough of low pressure accelerating northeastward, rising up the U.S. East Coast. USA.
Shortcomings of the Saffir-Simpson Scale: Comparison with Hurricane Idalia (2023) and Hurricane Florence (2018)
As regular Eye of the Storm readers know, the Saffir-Simpson intensity scale is based solely on maximum sustained winds; by design, it does not take into account any other very real dangers of hurricane landfall. Rain is a typical example. Inland flooding has accounted for more than half of all U.S. hurricane deaths since 2013 as hurricanes fueled by warming waters and a moist atmosphere bring more rain. We are not told how specific hurricanes might produce large amounts of flooding.
Debbie made landfall in the Big Bend, Florida area, almost exactly where Category 3 Hurricane Idalia made landfall on August 30, 2023, with sustained winds of 115 mph and a storm surge of 8 to 12 feet (2.43 to 3.66 meters). Idalia killed 12 people and caused $3.6 billion in damage, a very low cost figure for a major hurricane that made landfall in the United States. The storm hit the sparsely populated coast and did not stop on land; the storm's maximum rainfall was five inches (12.7 cm) to 10 inches (25.4 cm) along a relatively narrow path from northern Florida to southern North Carolina. Strip landing. Therefore, although Idalia was classified as a Category 3 storm at landfall, its effects were more typical of a Category 1 storm, and the name Idalia was not removed from the rotation of hurricane names.
Debbie's Storm Surge
Debbie brought three to four feet of storm surge to much of Florida's west coast, from Naples to Tampa Bay, causing mild to moderate coastal flooding. The highest surge recorded by a tide gauge was measured at Cedar Island, where a surge of over six feet (1.82 meters) was recorded. Fortunately, the peak surge occurred at low tide and the final water level at the station was only the sixth highest on record.
Debbie brought the third-highest water ever recorded to Naples, Florida, where accurate records date back to 1965. This is the type of behavior one would expect to see in the era of climate change, as rising sea levels make it easier to set new water height records. Debbie brought the fifth-highest water levels ever recorded to Fort Myers, Florida, where accurate records date back to 1965.
tornado
Debbie spawned six tornadoes in western Florida on Sunday, causing minor damage, according to storm reports from the National Oceanic and Atmospheric Administration's Storm Prediction Center. The center has classified parts of northeast Florida, coastal Georgia and coastal South Carolina as a “mild risk” (level two out of five) of severe weather for Monday, with some weak tornadoes expected to the right of Debbie's center .
This article was translated by Perla Marvell.
