1947 Fort Lauderdale Hurricane - Meteorological History

Meteorological History

Hurricane Four was first monitored as an area of low pressure over French West Africa on September 2, 1947. Steadily tracking westward, the system was quickly classified as a depression before moving into the Atlantic Ocean near Dakar, Senegal, on September 4. Shortly thereafter, weather agencies lost track of the system over water due to a lack of ships in the region. However, later analysis determined that the cyclone obtained tropical storm status, with maximum sustained winds of 50 mph (85 km/h), during the afternoon of September 4. The storm quickly intensified as it tracked nearly due west, attaining winds of 75 mph (120 km/h), equivalent to a Category 1 hurricane on the Saffir–Simpson Hurricane Scale, roughly 18 hours after being classified a tropical storm. The hurricane maintained this intensity for nearly five days, taking a southwest turn on September 7 before turning to the northwest two days later, when the steamship Arakaka provided confirmation of its existence. Beginning then, the cyclone began to intensify more rapidly as its forward speed increased; between September 10 and 15, reconnaissance missions by the United States Navy began monitoring the hurricane. At 1500 UTC on September 11, a navy aircraft first penetrated the storm; in less than 24 hours, the storm strengthened, with another mission registering a barometric pressure of 977 mb (28.84 inHg), a drop of 22 mb in 24 hours. On September 13, another airplane at 1930 UTC confirmed that the storm had deepened further to 952 mb (28.11 inHg) and its eye shrunk to 6 nmi (11 km); by that time the hurricane had reached Category 4 intensity. The same mission reported a double eyewall, a feature replaced by a large eye by the time the storm hit the Bahamas and Florida. The next day, the storm attained the minimum pressure, 938 mb (27.70 inHg), recorded by aircraft reconnaissance during its life span, yet continued to intensify thereafter. Early on September 16, as its movement slowed greatly and turned westward near the northern Bahamas, it attained its peak intensity of 160 mph (260 km/h). Following the phonetic alphabet from World War II, the U.S. Weather Bureau office in Miami, Florida, which then worked in conjunction with the military, named the storm George, though such names were apparently informal and did not appear in public advisories until 1950, when the first Atlantic storm to be so designated was Hurricane Fox.

While retaining its intensity, the storm, its northwesterly course having been blocked by a ridge of high pressure, crossed the northern portion of the Abaco Islands, where on Elbow Cay the Hope Town weather station simultaneously estimated winds of 160 mph (260 km/h) and recorded 960.7 mb (28.37 inHg) as the center passed just to the north. About 24 hours later on September 17, it made landfall near Fort Lauderdale, Florida, as a strong Category 4 hurricane with maximum sustained winds near 155 mph (250 km/h)—only three other hurricanes, all Category 5 (the 1935 Labor Day hurricane, Camille, and Andrew), are estimated to have had higher maximum sustained winds upon striking the United States. To this date, the hurricane remains the only major hurricane to have struck Broward County, Florida, at that strength, and the only one to pass directly over the county seat of Fort Lauderdale, though the 1926 Miami hurricane and Hurricane King caused significant damage in the county. About 1700 UTC, the cyclone produced peak gusts of 155 mph (250 km/h) and sustained winds of 122 mph (195 km/h) at Hillsboro Inlet Light near Pompano Beach, Florida; the gust was the highest measured wind speed recorded in the state of Florida until 1992, when Hurricane Andrew produced a gust of 177 mph (285 km/h) at Perrine. The station also reported a pressure of 947.2 mb (27.97 inHg), the lowest during the passage of the storm over Florida, though its accuracy is uncertain as Fort Lauderdale, in the eye to the south, reported higher pressures, while winds at the lighthouse remained at hurricane force. The hurricane moved slowly inland near 10 mph (16 km/h), and it diminished to a Category 2 hurricane over the Everglades. Early on September 18, the cyclone entered the Gulf of Mexico near Naples, producing wind gusts of 120 mph (190 km/h) at Sanibel Island Light near Fort Myers.

Once over water, the hurricane had diminished to about 90 mph (145 km/h); though no further reconnaissance missions were dispatched to estimate its intensity over the Gulf of Mexico, it is believed to have begun reintensifying as it turned west-northwest and its forward motion increased to 15 mph (25 km/h). On September 19, the hurricane moved ashore over Saint Bernard Parish, Louisiana, as a major hurricane with sustained winds of at least 115 mph (185 km/h). The hurricane quickly weakened as it moved over the New Orleans metropolitan area, although its strong winds gusted to 125 mph (175 km/h) in New Orleans, Louisiana. The eye passed over Baton Rouge, the state capital, between 2000 and 2020 UTC, with anemometers registering sustained winds of 96 mph (154 km/h) at 2045 UTC. On September 20, the storm rapidly weakened to a tropical depression over northeastern Texas, but the remnant circulation turned northeast over southeastern Oklahoma and northwest Arkansas. On September 21, it dissipated over southern Missouri.