1999 Pacific hurricane season

A La Niña lull

1999 ranks among the least active Pacific seasons on record, and a strong La Niña, which raised wind shear and cooled the water off Mexico, explains the shortage of storms. Its NHC-based count gives nine named storms against an average of sixteen, with six hurricanes and two major hurricanes close to normal. The site counts 10 tropical storms and 7 hurricanes because it also includes Tanya, a western Pacific-numbered system whose archive track begins near 30°N, just east of the date line, in August and which reached 70 kt. Accumulated cyclone energy came to 96.8 in the site's calculation.

The Central Pacific Hurricane Center recorded near-normal sea surface temperatures except for cool anomalies of 1 to 2 °C near the equator and southeast of Hawaii. Three tropical cyclones entered its area, all from the east: Tropical Depression Four-E and Hurricanes Eugene and Dora, between 24 July and 20 August. Air Force Reserve crews flew three missions into Eugene and two into Dora, and a NOAA Gulfstream IV flew two missions into each; during one Dora flight the Gulfstream made its first penetration of a hurricane.

Adrian's surf and Beatriz at sea

Hurricane Adrian formed on 18 June and paralleled the Mexican coast, peaking at 85 kt on 20 June without making landfall. Its outer bands still proved deadly. The NHC cited Reuters reports of four people swept off a Chiapas beach by a huge wave on 18 June, when Adrian's winds were only 30 to 40 kt, and two drownings with one person missing in inland river flooding. In all, Adrian caused six deaths in Mexico; its rain reached 15.75 inches of rain at Coyutla and fed a hailstorm in Michoacán that left about 2,000 people homeless.

Beatriz formed on 9 July, went through an eyewall replacement and reached 105 kt around 0600 UTC on 13 July with a clear 20 n mi eye, about 800 n mi from land. It stayed at sea, and the NHC received no reports of damage. Tropical Storm Calvin and three short-lived depressions followed in late July, all far from land.

Dora and Eugene cross toward Hawaii

Dora and Eugene formed a day apart in early August. Eugene peaked at 95 kt around 1800 UTC on 9 August near 133°W, which the NHC notes is far west of where eastern Pacific storms usually peak. It entered the central Pacific as a 70 kt hurricane, weakened south of Hawaii and ended about 550 miles southeast of Johnston Atoll on 15 August. It brought minor surf to the Big Island and about two inches of rain to windward Maui and the Big Island.

Dora formed on 5 August about 300 miles south of Acapulco and ran almost due west. A small eye formed on 9 August, and the NHC estimated a peak of 120 kt and 943 mb at 0000 UTC on 12 August, the strongest winds and lowest pressure of the season. It held 115 to 120 kt from 10 to 13 August, then entered the central Pacific at 75 kt.

Dora strengthened again to 100 kt on 16 August while passing about 200 miles south of South Point on the Big Island. There, surf of 8 to 12 feet hit the southeast and northeast shores and gusts of 40 to 50 kt blew at elevations near 5,000 feet; Beaches, campsites and trails closed in Kaʻū and Puna. Dora passed about 80 miles south of Johnston Atoll on 18 August, where gusts reached 35 to 40 kt, and crossed the date line as a 60 kt tropical storm. It was the first storm since Hurricane John in 1994 to exist in all three North Pacific basins. The NHC knows of no casualties or damage.

Greg's floods and a quiet finish

Tropical Storm Fernanda peaked at 55 kt in mid-August without reaching land, and a brief depression, Eleven-E, died west of the tip of Baja California on 24 August after dropping 8.27 inches of rain at Los Cabos.

Greg grew from the southern part of the wave that spawned Atlantic Tropical Storm Emily and formed on 5 September very near Manzanillo. Los Cabos radar showed a ragged eye on 6 September, and Greg became a 65 kt hurricane that evening while approaching southern Baja California. It weakened before its center crossed the Cabo San Lucas area around 2100 UTC on 7 September, with estimated winds of 50 kt. El Nuevo Herald reported torrential rains and flooding across Colima, Jalisco, Michoacán, Nayarit and Sinaloa, and the NHC cited nine deaths from the rains. Greg caused ten deaths, dropped 22.23 inches of rain at Tecomán and left about 2,000 people homeless, and its remnant moisture fed thunderstorms, power cuts and small wildfires in California.

Hilary briefly became a 65 kt hurricane early on 20 September about 200 n mi southwest of the tip of Baja California, then lost its convection over cool water and ended west of Cabo San Lázaro without affecting land. Tropical Storm Irwin closed the season, peaking at 50 kt on 9 October under east-northeasterly shear and dissipating on 11 October with no reported casualties or damage.