2005 Pacific hurricane season

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 over the open Pacific.

Pre-season forecasts

{| class="toccolours" cellspacing=0 cellpadding=3 style="float:right; margin-left:1em; text-align:right; clear: right;"

|+Predictions of tropical activity in the 2005 season

|- style="background:#CFCFCF; text-align:center;×÷≥"

|align="center"|Source

|align="center"|Date

|align="center"|Named storms

|align="center"|Hurricanes

|align="center"|Major hurricanes

|align="center"|Ref

|align="left"|Eastern

|align="left"|Average

|15–16

|4–5

| 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

thumb|270px|Three simultaneous tropical cyclones existed on September 22. Jova, Kenneth and Max

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 .

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 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. 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 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 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 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.

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 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. 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.

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 .

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 in Glenwood, Hawaii. 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 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 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. consistent with a ragged eye on infrared satellite imagery. Hilary entered a progressively cooler ocean after peak, resulting in the loss of deep convection. The system fell to tropical storm intensity late on August 24, tropical depression intensity late on August 25, and degenerated to a remnant low by 00:00 UTC on August 26. The low moved generally west until dissipating early on August 28. With the center located on the edge of deep convection, Irwin attained peak winds of early on August 26 before northeasterly wind shear prompted weakening. The cyclone fell to tropical depression intensity early on August 28 and further degenerated to a remnant low by 18:00 UTC on August 28. The low moved west and then southwest until dissipating on September 3.

Nearby dry air acted to temporarily but significantly weaken Jova's spiral banding despite a favorable upper-level environment. By 12:00 UTC on September 19, however, it intensified into the first major hurricane – a Category 3 or larger on the Saffir–Simpson hurricane wind scale – of the season; twelve hours later, it attained peak winds of . Cooler ocean temperatures took their toll on Jova as it progressed westward, with Jova falling to tropical storm intensity early on September 23, dropping to tropical depression intensity early on September 24, and ultimately dissipating by 06:00 UTC on September 25 a few hundred miles north of Hilo, Hawaii.

After maintaining peak strength for about 18 hours, Kenneth began a sharp weakening trend due to north-northeasterly wind shear. While weakening, the hurricane turned to a southwest drift, due to a weakness in steering currents. By September 21, its circulation was exposed to the east-northeast of the convection.

The remnants of Kenneth caused flooding in Hawaii. Rains caused the Kaukonahua Stream to burst its banks and Lake Wilson to overflow behind the Wahiawa Dam. On Kauai, flooding occurred on the Hanalei River, which resulted in the closure of the Kuhio Highway at the Hanalei Bridge.

Tropical Storm Lidia

In mid-September, a series of tropical waves entered the eastern Pacific from the Caribbean Sea. One of these waves led to the formation of a tropical depression by 12:00 UTC on September 17, which intensified into Tropical Storm Lidia and attained peak winds of six hours later. Initial forecasts were of low confidence, with forecasters citing uncertainty in whether Lidia or a developing disturbance to its east would become the dominant cyclone. Nearly stationary, the cyclone's cloud pattern soon became distorted by the much larger circulation of developing Tropical Storm Max. Lidia weakened to a tropical depression late on September 18 and was completely absorbed by Max twelve hours later.

Tropical Storm Norma

An area of disturbed weather formed south of Mexico on September 19, followed by the formation of a broad area of low pressure within the disturbance two days later. A few small vortices were observed within the broad low over subsequent days, one of which cled to the formation of a tropical depression by 00:00 UTC on September 23. On a west-northwest course, the depression intensified into Tropical Storm Norma twelve hours later and ultimately attained peak winds of by 18:00 UTC on September 24 as the circulation became centrally located within the convection and banding features developed. Norma turned northwest as easterly wind shear increased, causing it to weaken to a tropical depression by 18:00 UTC on September 26 and degenerate to a remnant low a day later. The low turned south and east, persisting for several days before dissipating on October 1.

Hurricane Otis

A tropical wave moved off Africa on September 9, the northern half of which led to the formation of Hurricane Philippe. The southern portion of the wave continued westward, crossing into the eastern Pacific Ocean on September 22. As the wave entered a monsoon-like environment, convection increased on September 23, although proximity to land and wind shear prevented quick development. A tropical depression formed at 00:00 UTC on September 28, while located about to the south of Manzanillo, Mexico. It moved to the southwest at first before turning to the northwest. On September 29, the depression strengthened into Tropical Storm Otis. That evening, wind shear relented and conditions became more favorable for the storm's intensification. Convection wrapped almost fully around the center, and early on September 3, Otis was upgraded to a Category 1 hurricane on the Saffir–Simpson Hurricane Scale. A ragged eye feature developed, , and despite moving over cooler waters, Otis intensified to reach maximum sustained winds of 105 mph (165 km/h) early on October 1. The barometric pressure was estimated at 970 mbar (hPa; 28.64 inHg). Soon after, Otis weakened due to southwesterly wind shear and dry air. The cloud pattern associated with the hurricane deteriorated on October 2, and the center of circulation was separated from the convective activity. Otis weakened to a tropical storm and drifted erratically toward the north-northwest as a result of weak steering currents. Over increasingly cold waters, the cyclone further weakened to a depression on October 3 and consisted of a small swirl of low-level clouds. It became a remnant low pressure area the next day. The system abruptly turned southeastward and drifted parallel to the coast of the Baja California Peninsula until dissipating on October 5.

The Mexican government issued hurricane warnings for the west coast of the Baja California peninsula from Agua Blanca to San Andresito. Five communities in Mexico, including Cabo San Lucas, declared a state of emergency. The port in Cabo San Lucas was closed due to the storm's threat. At Cabo San Lucas, an automated weather station recorded a wind gust to on September 30, with sustained winds of . The storm caused flooding in parts of the southern Baja California peninsula.

The remnant low continued westward, now steered by low-level easterly flow across the basin. Early on October 19, deep convection began to reform near the circulation, leading to the re-designation of a tropical depression by 12:00 UTC that day. Like its previous incarnation, however, a combination of dry air and southeasterly wind shear prevented the cyclone from intensifying to tropical storm status, with only a few curved band in its northern semicircle. Steady weakening occurred until the depression degenerated to a remnant low for a second time around 00:00 UTC on October 21. The remnant low turned southwestward before becoming reabsorbed into the ITCZ well southwest of the Baja California peninsula twelve hours later. This was the same list used for the 1999 season. No names were retired from this list by the World Meteorological Organization following the season, and it was used again for the 2011 season.

{| width="90%"

Adrian
Beatriz
Calvin
Dora
Eugene
Fernanda
Greg
Hilary

Irwin
Jova*
Kenneth*
Lidia
Max
Norma
Otis

For named storms that form in the North Pacific between 140°W and the International Date Line, the names come from a series of four rotating lists. Names are used one after the other without regard to year, and when the bottom of one list is reached, the next named storm receives the name at the top of the next list.