2005 Pacific hurricane season

Season overview

By the number of tropical storms, 2005 was an ordinary year in the eastern Pacific; by the number of hurricanes it fell short. The 1971 to 2004 average was about 15 named storms, 9 hurricanes and 4 major hurricanes, so the season matched the first figure but produced two fewer hurricanes and half as many major ones. Accumulated cyclone energy came to 96.6 units. Before the season, NOAA had called for 11 to 15 named storms, 6 to 8 hurricanes and 2 to 4 major hurricanes, noting that a busy Atlantic, as expected that year, tends to go with a quieter eastern Pacific.

The published post-season analysis summarised in the season article ties the rhythm of the year to the Madden–Julian oscillation: most storms formed while its favourable phase, with upper-level divergence, passed over the basin, and the long gaps between storms matched spells of upper-level convergence. Cooler than average sea surface temperatures during the peak months helped hold hurricane numbers down, extending the run of generally lower activity that had begun around 1995. The El Niño–Southern Oscillation stayed near neutral through the year.

The site's archive tracks 17 systems between 17 May and 20 October: 15 reached tropical storm strength, 7 became hurricanes and 2 became major hurricanes, with none reaching Category 5. The National Hurricane Center's best track, used by the season article, gives the same 15 named storms, 7 hurricanes and 2 major hurricanes, and counts the same 17 depressions once the two brief phases of the October depression, Sixteen-E, are treated as one system.

How the season unfolded

The season opened unusually early and unusually far east. Hurricane Adrian formed on 17 May just south of 10°N, about 400 nautical miles west-southwest of El Salvador, and instead of heading west like most eastern Pacific storms it moved east-northeast ahead of a strong trough over Mexico. It briefly reached 70 kt on 19 May, making it the season's first hurricane, before shear tore it apart near the Central American coast.

June and July brought only short-lived tropical storms. Beatriz, Calvin and Dora formed close to the Mexican coast and lasted two or three days each as tropical storms, held back by shear, cooler water or the mountainous coastline; Calvin and Dora both ran parallel to southwestern Mexico. Eugene in mid-July was the strongest of the group, reaching 60 kt on 19 July before cooler water off Baja California weakened it quickly.

August was steadier. A short-lived tropical depression formed near 140°W on 3 August, the only cyclone to develop in the central Pacific all year. Hurricane Fernanda and Tropical Storm Greg then ran side by side from 11 August, with shear from Fernanda helping to keep Greg a weak tropical storm. Hurricane Hilary followed on 19 August and grew into a Category 2 storm south of Mexico, and Tropical Storm Irwin closed the month. Irwin grew from the southern half of the same African tropical wave whose northern half became Hurricane Katrina in the Atlantic.

After a quiet start to September, the season's busiest spell arrived. Between 12 and 28 September six storms formed: Jova, Kenneth, Lidia, Max, Norma and Otis. Tropical Storm Lidia lasted barely a day before the larger circulation of Hurricane Max absorbed it, and on 22 September Jova, Kenneth and Max were all active at once. Then activity stopped abruptly. The only October formation was Sixteen-E, which was a depression twice between 15 and 20 October but never became a named storm. The season article notes that only three other seasons since 1971, 1989, 1995 and 1996, ended October without a named storm forming during the month.

Strongest storms

Hurricane Kenneth was the season's strongest and longest-lived storm. It formed on 14 September roughly 790 nautical miles southwest of Cabo San Lucas, became a hurricane two days later and peaked at 115 kt, Category 4, with a central pressure of 947 hPa on 18 September over open ocean. Shear then knocked it down to a tropical storm, but it regained hurricane strength on 25 September before drifting into the central Pacific and finally dissipating just east of the Big Island of Hawaii on 30 September, about 16 days after it formed.

Hurricane Jova, the season's other major hurricane, took a slower path to its peak. It spent three days as a depression before becoming a tropical storm on 15 September, then strengthened steadily as it moved west, crossing 140°W as a 90 kt hurricane on 18 September. In the central Pacific it reached Category 3 and peaked at 110 kt and 951 hPa on 20 September, about 850 miles east-southeast of Hilo. The Central Pacific Hurricane Center called it the strongest tropical cyclone in its area since Hurricane Ele in 2002. Jova held Category 3 strength for 36 hours before an upper trough near Hawaii weakened it, and it dissipated well north of the islands on 25 September.

No other storm reached major hurricane strength. Hurricane Hilary in August and Hurricane Otis at the turn of September and October each peaked at 90 kt, Category 2, while Adrian, Fernanda and Max stayed at Category 1.

Landfalls and impacts

No storm of tropical storm strength or higher made landfall during the season, the second year in a row without one. The only landfall was Adrian's: after passing about 75 nautical miles from El Salvador, closer than any eastern Pacific hurricane on record since 1949, it weakened offshore and came ashore as a tropical depression through the Gulf of Fonseca into Honduras on 20 May. Heavy rain caused flooding, washed-out roads and mudslides in El Salvador and Honduras, with flooding also in Guatemala and Nicaragua, and media reports put evacuations in El Salvador at up to 23,000 people. The NHC recorded one death directly caused by Adrian, from flooding in Nicaragua. The season article's tally of media reports lists five deaths in total across Guatemala, El Salvador and Nicaragua, and business losses of about $12 million (2005 US dollars) in El Salvador alone.

Several storms threatened Mexico without striking it. Hurricane Hilary brought tropical storm force winds to the coast near Manzanillo on 21 August, and Tropical Storm Eugene briefly prompted a tropical storm watch for southern Baja California. Hurricane Otis led to hurricane warnings for part of the Baja California peninsula, but its core stayed offshore and weakened over cool water. An elevated automated station at Cabo San Lucas measured tropical storm force winds, and media reported some flooding in the southern peninsula. The NHC reports for Hilary, Eugene and Otis record no damage or casualties.

Hawaii felt the season through storm remnants rather than direct hits. The remains of the central Pacific depression that formed on 3 August crossed the Big Island on 7 and 8 August, dropping 8.80 inches of rain in 48 hours at Glenwood. Kenneth's remnant swirl moved over the Big Island on 30 September and, interacting with an upper trough, fed heavy rain on 1 October: 6 to 12 inches fell in Nuuanu and Kalihi valleys on Oahu, Lake Wilson overflowed at Wahiawa Dam, and flash flooding on Kauai's Hanalei River closed the Kuhio Highway at the Hanalei Bridge. The Central Pacific Hurricane Center recorded no deaths and no significant property damage in its area.

Forecasts, names and other context

Adrian also changed the landfall record after the season. Forecasters in real time judged that it had come ashore in El Salvador as a borderline Category 1 hurricane. Post-storm analysis found instead that the low-level centre had turned east and stayed offshore, so Andres of 1997, a tropical depression, remained the only landfall in El Salvador since 1949. Adrian became only the third eastern Pacific cyclone since 1949 to make landfall in Central America, all of them as depressions.

NHC track forecasts for Kenneth and Jova were well below the 1995 to 2004 average errors at every lead time, but intensity was harder. Jova's 72 to 120 hour intensity forecasts were too low by as much as 55 kt, because the cooler water and shear that forecasters expected to hold it back did not materialise. The storm's approach, only weeks after Hurricane Katrina hit the US Gulf Coast, drew close public and media attention in Hawaii.

Storms east of 140°W took names from the list first used in 1999, running from Adrian to Otis, and no names were retired, so the list returned in 2011. No storm formed or was named between 140°W and the International Date Line; the only named storms in the central Pacific were Jova and Kenneth, which carried their names in from the east.