The 2005 Pacific hurricane season was a near-average Pacific hurricane season which produced fifteen named storms, seven hurricanes and two major hurricanes. It was also the second consecutive season in which no tropical cyclone of at least tropical storm intensity made landfall. The season officially began on May 15 in the East Pacific Ocean, and on June 1 in the Central Pacific; they ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Pacific basin. However, the formation of tropical cyclones is possible at any time of the year.
Activity began with the formation of Hurricane Adrian, the fourth-earliest-forming tropical storm on record in the basin at the time. Adrian led to flash flooding and several landslides across Central America, resulting in five deaths and $12 million (2005 USD) in damage. Tropical storms Calvin and Dora caused minor damage along the coastline, while Tropical Storm Eugene led to one death in Acapulco. In early October, Otis produced tropical storm-force winds and minor flooding across the Baja California peninsula. The remnants of Tropical Depression One-C in the central Pacific, meanwhile, caused minor impacts in Hawaii. The strongest storm of the season was Hurricane Kenneth, which attained peak winds of 130 mph (210 km/h) over the open Pacific.
Pre-season forecasts
The first forecast for the 2005 season was produced by the Servicio Meteorológico Nacional (SMN) in the second month of the year. In their report, the organization cited a list of analog years – 1952, 1957, 1985, 1991, and 1993 – with similar oceanic and atmospheric patterns. An overall total of 17 tropical storms, 10 hurricanes, and 7 major hurricanes was forecast, above the average. The National Oceanic and Atmospheric Administration (NOAA), meanwhile, released their seasonal outlook on May 16, predicting 11 to 15 named storms, 6 to 8 hurricanes, and 2 to 4 major hurricanes. The organization noted that when the Atlantic basin was busier than average, as expected in 2005, the eastern Pacific generally saw lesser activity. That same day, NOAA issued a forecast for activity across the central Pacific, expecting 2 to 3 tropical cyclones to occur across the basin. A normal season averaged 4 to 5 tropical cyclones, including 1 hurricane. A near-normal El Niño–Southern Oscillation existed across the equatorial Pacific throughout 2005, which indicated conditions generally less conducive for activity there.
Seasonal summary
The Accumulated Cyclone Energy (ACE) index for the 2005 Pacific hurricane season as calculated by Colorado State University using data from the National Hurricane Center was 96.6 units. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 mph (63 km/h).
The season's first tropical cyclone, Adrian, developed on May 17 and reached its peak as a Category 1 hurricane. Named storms are infrequent in May, with one tropical storm every two years and a hurricane once every four years. At the time, Adrian was the fourth earliest tropical cyclone to form in the eastern Pacific since reliable record-keeping began in 1971. Activity throughout the remainder of the season was far less notable, with 16 tropical cyclones, 15 named storms, 7 hurricanes, and 2 major hurricanes. The long-term 1971–2004 average suggests an average season to feature 15 named storms, 9 hurricanes, and 4 major hurricanes. October in particular was notably quiet, with the formation of only one tropical depression; only three other seasons, 1989, 1995, and 1996, ended the month without the designation of a named storm.
Analysis of the environment suggested that most storms formed during the passage of the positive Madden–Julian oscillation and its associated upper-air divergence, which is favorable for tropical cyclone formation. Extended reprieves in tropical activity were connected to upper-level convergence. Another factor that led to a below-average season was the presence of cooler than average ocean temperatures during the peak months, helping to extend the period of lesser activity that began throughout the eastern Pacific around 1995.
Systems
Hurricane Adrian
In early to mid-May, several areas of disturbed weather moving westward from Central America aided in the formation of a broad area of low pressure well south of Mexico. A poorly defined tropical wave became intertwined with the larger system over subsequent days, leading to the formation of a tropical depression at 18:00 UTC on May 17. The nascent cyclone intensified into Tropical Storm Adrian six hours later. Despite the effects of moderate wind shear, the system steadily organized as convection became concentrated around the center, and Adrian attained its peak with winds of 80 mph (130 km/h) at 18:00 UTC on May 19. Environmental conditions became less conducive thereafter as downsloping from mountains along the coastline of Mexico combined with the already-marginal upper-level winds. The cyclone fell to tropical storm intensity at 00:00 UTC on May 20, tropical depression intensity at 18:00 UTC that day, and dissipated at 06:00 UTC on May 21 along the coastline of Honduras in the Gulf of Fonseca.
Hurricane Adrian was responsible for five deaths: two died in a mudslide in Guatemala, a pilot crashed in high winds and a person drowned in El Salvador, and a person was killed by flooding in Nicaragua. Heavy rainfall up to 16.4 in (420 mm) in El Salvador led to landslides, damaged roads, and flash flooding. In Honduras, a few shacks were destroyed, a few roads were blocked, and some flooding occurred; similar effects were noted in Guatemala and Nicaragua. Monetary losses topped $12 million (2005 USD) in El Salvador alone.
Tropical Storm Beatriz
A tropical wave emerged into the Atlantic on June 8 and entered the East Pacific over a week later, merging with a number of disturbances within a broad area of low pressure south of Mexico on June 17. The disturbance's cloud pattern—although initially elongated—steadily coalesced, leading to the formation of a tropical depression at 18:00 UTC on June 21 and further intensification into Tropical Storm Beatriz at 12:00 UTC on June 22. The system battled easterly wind shear and marginal ocean temperatures on its west-northwest track, attaining peak winds of 50 mph (80 km/h) the next day before weakening to tropical depression intensity at 00:00 UTC on June 24. Six hours later, it degenerated into a remnant low which slowed and turned southward prior to dissipating early on June 26.
Tropical Storm Calvin
A tropical wave emerged off the western coast of Africa on June 11, remaining inconspicuous until reaching the southwestern Caribbean Sea eight days later. The system entered the eastern Pacific on June 21, where steady organization led to the formation of a tropical depression around 06:00 UTC on June 26 while located 330 mi (530 km) south-southeast of Acapulco, Mexico. Upon formation, the cyclone moved north-northwest and then west-northwest under the dictation of a subtropical ridge to its north. It intensified into Tropical Storm Calvin at 18:00 UTC on June 26, attaining a peak intensity of 50 mph (80 km/h) early the next morning in conjunction with a well-defined spiral band on radar. Calvin then dove west-southwest and weakened as strong wind shear exposed the storm's circulation; it fell to tropical depression status at 12:00 UTC on June 28 and further degenerated to a remnant low by 06:00 UTC the next day. The low moved generally westward before dissipating well southwest of the Baja California peninsula on July 3. As a tropical cyclone, Calvin caused only minor damage to roofs and highways, flooded a house, and toppled two trees.
Tropical Storm Dora
The genesis of Tropical Storm Dora can be attributed to a westward-moving tropical wave that emerged off Africa on June 18. By July 3, the wave passed through the Gulf of Tehuantepec, where broad cyclonic flow began to develop along its axis. Following further organization, the disturbance intensified into a tropical depression by 00:00 UTC on July 4 and further strengthened into Tropical Storm Dora six hours later. The cyclone moved north-northwest and then west-northwest, paralleling the coastline of Mexico under the influence of a subtropical ridge, where landslides and mudslides cut communication to 12 mountain villages. Under a moderate easterly wind shear regime, Dora ultimately changed little in strength, peaking with winds of 45 mph (72 km/h) as the center became obscured on the eastern edge of extremely deep convection. A track over colder waters caused the storm to fall to tropical depression intensity late on July 5 and degenerate into a remnant low by 12:00 UTC on July 6. The low then dissipated six hours later.
Tropical Storm Eugene
A tropical wave first identified over the Caribbean Sea on July 10 entered the eastern Pacific four days later. The disturbance organized as banding features became distinct, leading to the formation of a tropical depression by 06:00 UTC on July 18. The cyclone intensified into Tropical Storm Eugene six hours later as a mid-level ridge steered it generally northwest. Amid an environment of light wind shear, Eugene steadily organized to reach peak winds of 70 mph (110 km/h) by late on July 19, although it is possible the storm briefly attained hurricane intensity. Already tracking over cooler waters, Eugene quickly weakened immediately after its peak, becoming a tropical depression by 12:00 UTC on July 20 and degenerating into a remnant low twelve hours later. The low continued northwest before losing its character on July 22. As a tropical cyclone, Eugene flooded streets (which displaced six vehicles), left at least 30 houses inundated, and caused one death after a man's boat overturned.
Tropical Depression One-C
In late July to early August, an organized thunderstorm cluster persisted within the Intertropical Convergence Zone (ITCZ). Upon further development, the disturbance was designated as a tropical depression as it tracked swiftly west, the first and only cyclone to form in the central Pacific throughout the season. Despite initial forecasts of a minimal tropical storm, increasing wind shear and cooler ocean temperatures prompted the depression to instead dissipate by 00:00 UTC on August 5, having only attained peak winds of 30 mph (48 km/h).
As a tropical cyclone, Tropical Depression One-C had no impact on land. However, the remnants of the depression dropped moderate to heavy rainfall in Hawaii, particularly on the Island of Hawaii. Rainfall totals measured up to 8.8 in (220 mm) in Glenwood, Hawaii. Flash floods was reported in Kona and Ka‘ū, while minor flooding occurred in Hilo, Hamakua, and Kealakekua. In addition, minor street flooding was reported in several cities on that island; most notably, a nearly overflown drainage ditch threatened to submerge the Hawaii Belt Road. Some coffee plants were damaged.
Hurricane Fernanda
A vigorous tropical wave observed over western Africa in late July maintained vigor until passing the Windward Islands, becoming disorganized as it moved across South America and then into the eastern Pacific on August 5. Convection gradually redeveloped south of Mexico, leading to the formation of a tropical depression by 12:00 UTC on August 9 and intensification into Tropical Storm Fernanda twelve hours later. The nascent cyclone continued on a west-northwesterly course amid a favorable shear regime; it became a hurricane at 06:00 UTC on August 11 and attained peak winds of 85 mph (137 km/h) early the next day as a ragged eye became discernible. After leveling off in intensity, Fernanda fell to tropical storm intensity early on August 14, weakened to a tropical depression late on August 15, and degenerated into a remnant low by 06:00 UTC on August 16, all the while diving west-southwest. The low produced intermittent convection until dissipating the next day.
Tropical Storm Greg
A tropical wave that first crossed the western coastline of Africa on July 27 entered the eastern Pacific ten days later, gradually developing into a tropical depression by 06:00 UTC on August 11. The depression trekked west-northwest along the southern periphery of a subtropical ridge, intensifying into Tropical Storm Greg six hours after formation and reaching peak winds of 50 mph (80 km/h) by 00:00 UTC on August 12 as deep convection flared near the center and upper-level outflow became well established. Northerly shear from nearby Fernanda and a nearby upper-level trough caused Greg to level off and maintain its status as a low-end tropical storm for several days as steering currents collapsed. Drifting south, stronger upper-level winds caused Greg to weaken to tropical depression intensity by 18:00 UTC on August 14 before degenerating into a remnant low by 00:00 UTC on August 16. The low was absorbed into the ITCZ shortly thereafter.