Hurricane Emily (1993) - Meteorological History

Meteorological History

Hurricane Emily originated from an African tropical wave that passed through the Cape Verde Islands on August 17, 1993. The wave traversed the tropical Atlantic and developed a closed cyclonic circulation five days later, when the National Hurricane Center (NHC) classified it as a tropical depression. At the time, it was located 800 miles (1,300 km) east-northeast of Puerto Rico while moving toward the northwest. The depression remained poorly organized for several days, with an ill-defined circulation center and sporadic thunderstorms, in part due to unfavorable wind shear from an upper-level low to its north. On August 25, it became nearly stationary in response to weakening steering currents. After the upper environment became less hostile to development, a reconnaissance aircraft flight into the depression found unusually high sustained winds—an indication that the cyclone had quickly strengthened into a strong tropical storm. The NHC named the storm Emily and upgraded it to a hurricane the following day, based on reports of 75 mph (120 km/h) winds from reconnaissance aircraft.

Upon becoming a hurricane, Emily was centered roughly 1,000 mi (1,600 km) east of the Florida peninsula. A ridge of high pressure began to develop to its north on August 27, forcing the hurricane to curve toward the west. The cyclone's winds vacillated between tropical storm and hurricane force over the course of the day, although Emily resumed its strengthening by August 28, developing favorable upper-level outflow. Located over warm sea surface temperatures, the hurricane continued to improve in appearance on satellite images, as the barometric pressure within its eye steadily decreased. Emily turned to the northwest on August 29, when a shortwave trough eroded the southern periphery of the ridge. The NHC expressed uncertainty in forecasting Emily's track from thereon, stating that South Carolina, North Carolina, and other Mid-Atlantic states were at risk of a direct hit from the hurricane. As high pressure re-established itself near North Carolina, Emily briefly turned west-northwestward on August 30 before initiating a prolonged curve toward the north. By that time, the NHC forecast Emily to remain offshore, although one tropical cyclone forecast model predicted that the hurricane would move inland.

Early on August 31, a reconnaissance flight indicated that Emily had become a Category 2 hurricane on the Saffir–Simpson scale, and further intensification was expected because of warm water temperatures. Later that day, reconnaissance reported that Emily had intensified to a peak intensity of 115 mph (185 km/h), or a Category 3 major hurricane on the Saffir-Simpson scale; the aircraft also observed flight-level winds of 152 mph (245 km/h). At the time of its peak intensity, the hurricane was located 23 mi (37 km) east of Hatteras Island and was turning northward. Its eye, measuring 45 mi (75 km) in diameter, moved over Hatteras and the Pamlico Sound, which was considered a direct hit instead of a landfall. Continuing around the large high pressure area, Emily turned to the northeast after affecting the Outer Banks into an area of cooler water temperatures. The eye remained distinct, and Emily maintained much of its intensity through early on September 2. That day, the hurricane turned sharply to the east due to a trough. Increased wind shear weakened Emily, and its eye feature quickly dissipated. On September 3, Emily weakened to a tropical storm after turning to the southeast. The storm stalled and continued weakening, with significant deterioration of the convection. Late on September 4, Emily weakened further to a tropical depression, after only a small area of thunderstorms remained near the center. The system turned to the northeast and became extratropical on September 6 before dissipating shortly thereafter.