Hurricane Floyd

Hurricane Floyd was a very powerful Cape Verde hurricane which struck the east coast of the United States. It was the sixth named storm, fourth hurricane, and third major hurricane in the 1999 Atlantic hurricane season. Floyd triggered the fourth largest evacuation in US history (behind Hurricane Irma, Hurricane Gustav, and Hurricane Rita) when 2.6 million coastal residents of five states were ordered from their homes as it approached. The hurricane formed off the coast of Africa and lasted from September 7 to 19, becoming extratropical after September 17, and peaked in strength as a very strong Category 4 hurricane—just 2 mph short of the highest possible rating on the Saffir–Simpson Hurricane Scale. It was among the largest Atlantic hurricanes of its strength ever recorded, in terms of gale-force diameter. Floyd was once forecast to strike Florida, but turned away. Instead, Floyd struck The Bahamas at peak strength, causing heavy damage. It then moved parallel to the East Coast of the United States, causing massive evacuations and costly preparations from Florida through the Mid-Atlantic states. The storm weakened significantly, however, before striking the Cape Fear region, North Carolina as a very strong Category 2 hurricane, and caused further damage as it traveled up the Mid-Atlantic region and into New England. The hurricane produced torrential rainfall in Eastern North Carolina, adding more rain to an area already hit by Hurricane Dennis just weeks earlier. The rains caused widespread flooding over a period of several weeks; nearly every river basin in the eastern part of the state exceeded 500-year flood levels. In total, Floyd was responsible for 76 fatalities and $6.5 billion (1999 USD) in damage. Due to the destruction, the World Meteorological Organization retired the name Floyd. Floyd originated from a tropical wave that exited the west coast of Africa on September 2. The wave moved generally westward, presenting a general curvature in its convection, or thunderstorms, but little organization at first. By September 5, a center of circulation was evident within the convective system. Over the next day, the thunderstorms increased in intensity as they organized into a curved band. Aided by favorable outflow, the system organized further into Tropical Depression Eight late on September 7, located about 1,000 mi (1,600 km) east of the Lesser Antilles. With a strong ridge of high pressure to its north, the nascent tropical depression moved to the west-northwest, where environmental conditions favored continued strengthening, including progressively warmer water temperatures. On issuing its first advisory, the National Hurricane Center (NHC) anticipated that the depression would intensify into a hurricane within three days, a forecast that proved accurate. On its second advisory, NHC forecaster Lixion Avila stated that the depression had 'all the ingredients...that we know of...to become a major hurricane eventually.' Early on September 8, the depression became sufficiently well-organized for the NHC to upgrade it to Tropical Storm Floyd. The storm had a large circulation, but Floyd initially lacked a well-defined inner core, which resulted in only slow strengthening. The first Hurricane Hunters mission occurred on September 9, which observed the developing storm. On September 10, Floyd intensified into a hurricane about 230 mi (370 km) east-northeast of the Lesser Antilles. Around that time, the track shifted more to the northwest, steered by a tropical upper tropospheric trough north of Puerto Rico. An eye developed in the center of the hurricane, signaling strengthening. On September 11, Hurricane Floyd moved through the upper-level trough, which, in conjunction with an anticyclone over the eastern Caribbean, disrupted the outflow and caused the winds to weaken briefly. The hurricane re-intensified on September 12 as its track shifted more to the west, steered by a ridge to the north. That day, the NHC upgraded Floyd to a major hurricane, or a Category 3 on the Saffir-Simpson scale. Over a 24-hour period from September 12–13, Hurricane Floyd rapidly intensified, aided by warm waters east of The Bahamas. During that time, the maximum sustained winds increased from 110 to 155 mph (177 to 249 km/h), making Floyd a strong Category 4 hurricane. This was based a 90% reduction of an observation by the Hurricane Hunters, which recorded flight-level winds of 171 mph (276 km/h). Around the same time, the pressure dropped to 921 mb (921 hPa; 27.2 inHg), which was the third-lowest pressure for a hurricane not to reach Category 5 intensity in the Atlantic Ocean – only hurricanes Gloria and Opal had lower pressures than Floyd. round this time, tropical cyclone forecast models suggested an eventual landfall in the Southeastern United States from Palm Beach, Florida to South Carolina. At its peak, tropical storm-force winds spanned a diameter of 580 mi (930 km), making Floyd one of the largest Atlantic hurricanes of its intensity ever recorded. For about 12 hours, Hurricane Floyd remained just below Category 5 status while crossing The Bahamas. Late on September 13, the eye of the hurricane passed just north of San Salvador and Cat Islands. On the next day, the hurricane made landfalls on Eleuthera and Abaco islands. During this time, Floyd underwent an eyewall replacement cycle, in which an outer eyewall developed, causing the original eye to dissipate near Eleuthera. This caused a temporary drop in sustained winds to Category 3 status, only for Floyd to restrengthen briefly to a Category 4 on September 15. While approaching the southeastern United States, a strong mid- to upper-level trough eroded the western portion of the high-pressure ridge, which had been steering Floyd for several days. The break in the ridge caused Floyd to turn to the northwest. After the hurricane completed its eyewall replacement cycle, Floyd had a large 57 mi (93 km) eye. The large storm gradually weakened after exiting The Bahamas, due to drier air and increasing wind shear. On September 15, Floyd paralleled the east coast of Florida about 110 mi (170 km) offshore, as it accelerated to the north and north-northeast. At around 06:30 UTC on September 16, Hurricane Floyd made landfall in Cape Fear, North Carolina with winds of 105 mph (169 km/h), a Category 2. The eyewall had largely dissipated by that time. Continuing northeastward along a cold front, Floyd moved through eastern North Carolina and southeastern Virginia, weakening to tropical storm status by late on September 16. The storm gradually lost its tropical characteristics as it quickly moved through the Delmarva Peninsula, eastern New Jersey, Long Island, and New England. Late on September 17, Floyd transitioned into an extratropical cyclone near the coast of southern Maine. The storm continued to the northeast, passing through New Brunswick, Prince Edward Island, and Newfoundland on September 18. On the following day, a larger extratropical storm over the North Atlantic Ocean absorbed what was once Hurricane Floyd.