1984 Atlantic hurricane season

Many storms, few hurricanes

The National Hurricane Center counted 12 named tropical cyclones, 5 of them hurricanes, plus one subtropical storm, against a long-term average of 10 named storms and 6 hurricanes. The site's archive lists 13 tropical storms because it counts the August subtropical storm, which reached storm strength while subtropical. It records 5 hurricanes, 1 of them major, and an accumulated cyclone energy of 84.3. By the current best track, 1984 was the busiest season for named storms since 1971, with near-normal accumulated cyclone energy.

Most of the season played out over the western subtropical Atlantic. Only Arthur, Bertha, Fran, Gustav and Klaus traced back to the deep tropics, and none of those reached hurricane strength except Klaus, which formed in the eastern Caribbean. The other named storms, including Diana, grew from frontal cloud systems at higher latitudes. The NHC also measured the season by duration: its five hurricanes lasted 414 hours in all, which it judged near normal.

Forecasters worked with reduced satellite coverage. The GOES-East satellite failed on 30 July, and GOES-West moved east to 98°W by the end of August to cover part of the gap. Storms far out in the Atlantic, including the August subtropical storm and Tropical Storm Fran, sat at the edge of its view, and the European METEOSAT helped track Fran.

A late start and a September pileup

The archive's first tropical-stage observation comes on 11 June, from a depression that crossed northern Florida, and three more depressions formed before the first storm. No system reached storm strength until 19 August, an unusually late date. The subtropical storm formed north of Bermuda on 18 August, and Tropical Storms Arthur, Bertha and Cesar followed in the last days of the month.

September brought Diana, Edouard, Fran, Gustav, Hortense and Isidore. The NHC counted eight named storms during the month, the most in one month on record since 1886. Fran crossed the Cape Verde Islands as a tropical storm, and its floods damaged almost 1,100 homes and killed 29 to 32 people there. Hortense made three 180-degree turns in a week near Bermuda and held hurricane strength for 12 hours. Isidore came ashore on Florida's central east coast on 27 September, and the NHC attributed one death in central Florida and $1 million in damage to it.

Hurricane Diana's loop off Cape Fear

Diana formed on the end of a frontal trough north of the Bahamas on 8 September, came within 100 km of the Florida coast, then turned north parallel to Georgia and South Carolina. Hurricane warnings covered the coast from Georgia through North Carolina from 10 September. Aircraft penetrated the eye 50 times in 111 hours, and they measured the lowest pressure of 949 mb at 0000 GMT on 12 September, within 40 km of Cape Fear. The archive places Diana's peak of 115 kt at that time, Category 4, and the U.S. Coast Guard station at Oak Island measured a one-minute wind of 52 m/s.

Instead of moving ashore, Diana made a tight clockwise loop offshore for 30 hours, and its pressure rose 28 mb. The center crossed the coast near Cape Fear, due south of Wilmington, at about 0700 GMT on 13 September. The current best track gives a landfall wind of 90 mph, Category 1, well below the earlier peak. Diana then turned northeast and returned to sea.

The storm surge peaked at 1.7 m at Carolina Beach, and Wilmington collected 348 mm of rain over three days. The NHC estimated total damage at $65 million, of which $26 million was agricultural, and attributed three deaths to Diana.

Josephine, Klaus and a December hurricane

Hurricane Josephine formed east of the Bahamas on 7 October and stayed a hurricane for seven days as it crept north offshore, peaking at 90 kt on 12 October. It never came ashore, but its waves and high tides battered barrier islands from North Carolina to Massachusetts. NOAA aircraft dropped wind-measuring sondes around it and deployed three drifting buoys in its path.

Hurricane Klaus formed just south of Puerto Rico on 6 November and moved northeast, reaching 80 kt in the archive. Its southwesterly winds drove gales and rough seas onto the normally sheltered south and west coasts of the Virgin and Leeward Islands, damaging marine interests, and caused freshwater flooding in Puerto Rico. Klaus was the season's most damaging storm, with $157 million in damage in the Lesser Antilles in 1984 dollars.

Hurricane Lili formed along a stationary front south of Bermuda on 11 December and wandered as a subtropical storm for about a week before a ship report on 20 December showed it was becoming a hurricane. The NHC called it only the third December hurricane in the Atlantic since 1886. A hurricane watch went up for Puerto Rico and the Virgin Islands, but Lili weakened and broke up near Hispaniola on 24 December, the archive's last tropical-stage observation.