Alex (2004)

A broad low pressure area formed just northeast of the central Bahamas on 30 July 2004 and became Tropical Depression One on 31 July about 175 nautical miles east of Jacksonville, Florida. The system drifted north-northeast, became Tropical Storm Alex on 1 August, and then moved slowly toward the North Carolina coast. Alex reached hurricane strength early on 3 August as it approached the Outer Banks, passed just offshore of Cape Hatteras that day, then turned away from the U.S. coast, accelerated northeast, and reached major hurricane strength on 5 August well offshore near 38.5°N. Alex weakened rapidly over cooler waters and became extratropical on 6 August about 830 nmi east of Cape Race, Newfoundland; its circulation was absorbed by a larger low on 7 August.

Alex did not make a direct landfall, but its western eyewall passed over the North Carolina Outer Banks on 3 August and produced hurricane conditions there. The closest approach was about 9 nautical miles southeast of Cape Hatteras at about 1700 UTC 3 August, when category 1 hurricane winds affected the Outer Banks. Hurricane and tropical storm warnings were issued for portions of the North Carolina coast between 1 and 4 August as the storm approached.

The storm’s estimated peak intensity was 105 kt (about 121 mph) with a minimum central pressure of 957 mb, making Alex a category 3 (major) hurricane at peak on 5 August while well east of the U.S. coast. At closest approach to land near Cape Hatteras on 3 August, maximum sustained winds were estimated near 85 kt (about 98 mph), based on dropsonde and surface observations.

Storm surge reached near 6 feet on the sound (west) side of the Outer Banks, with the highest surge values reported at Buxton and Ocracoke Village. Waters along the lower Neuse and Pamlico rivers rose about 2–4 feet above normal. The highest measured rainfall was 7.55 inches at Ocracoke; Beaufort recorded 5.62 inches, and Doppler radar showed widespread 4–8 inch totals across parts of extreme southeastern Craven County, eastern Carteret County, Hyde County, and Dare County.

One person drowned in strong waves and lingering rip currents off Nags Head, North Carolina, two days after Alex’s passage. Significant storm-surge flooding and beach erosion occurred in Dare and Hyde counties; Buxton and Ocracoke Island experienced extensive flooding of vehicles and homes on the sound side. Wind caused minor structural damage, widespread tree and power-line damage, and insured flood losses of about $2 million. Total damage was estimated at no more than $5 million.

Notable aspects of Alex include its unexpected strengthening to major hurricane strength at unusually high latitude (only one other hurricane, Ellen in 1973, became a major hurricane farther north), and that peak intensity occurred after reconnaissance flights ended. Forecast track performance was near normal for the period, but intensity forecasts underpredicted Alex’s strengthening—especially the intensification near Cape Hatteras and the later development into a major hurricane.