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Hurricane Darby (2004)
Encyclopedia
Hurricane Darby was the first Eastern Pacific
major hurricane since Hurricane Kenna
in 2002
. The sixth tropical cyclone
, fourth named storm, and second hurricane of the 2004 Pacific hurricane season
, Darby developed from a tropical wave that emerged from the west coast of Africa on July 12. After crossing into the Eastern Pacific, the storm became a tropical depression on June 26. The system steadily intensified, and became a hurricane on 000 UTC July 28. Darby peaked as a Category 3 hurricane on the Saffir-Simpson Hurricane Scale
, though it quickly deteriorated due to cooler waters and increasing wind shear
. While Darby dissipated on August 1, the remnants of the tropical cyclone
affected the Hawaiian Islands
. The system produced high waves and heavy rainfall that led to extensive flash flooding. Numerous roads were closed, while minor landslides and rockslides were reported. Despite the effects, no fatalities or severe damages occurred.
emerged from the west coast of Africa on July 12 and entered the Atlantic Ocean. The wave progressed westward, crossing the Atlantic and Caribbean Sea before crossing into the Eastern Pacific on July 20. The west began to exhibit signs of development on July 23. The next day, the National Hurricane Center
(NHC) noted an associated area of showers and thunderstorms, indicating that gradual development
was possible. The system had become better organized and on July 25, the NHC continued to remark upon the potential for the weak low pressure area
—accompanied by disorganized convective activity—to develop. On July 26, the system became better-organized, and under favorable conditions it was upgraded to a tropical depression at 1200 UTC, while located about 760 miles (1,223.1 km) to the south-southwest of Cabo San Lucas, Mexico. Under the steering currents of a subtropical ridge of high pressure
, the depression continued moving westward.
Upon becoming a tropical cyclone
, the depression contained a somewhat well-defined low-level center of circulation
, as well as convective banding
. Based on Dvorak classifications, the storm was upgraded to a tropical storm at 0000 UTC on July 27; as the fourth tropical storm of the 2004 season
, it was named Darby by the NHC. Darby continued to intensify, with established outflow
and a well-defined banding feature. Later that day, forecasters predicted the storm to peak as a Category 1 hurricane on the Saffir-Simpson Hurricane Scale
. Darby was upgraded to a hurricane at 0000 UTC on July 28, at which time it began to turn towards the northwest. An eye
, embedded within the deep convection, developed later in the day. Darby attained Category 2 intensity at around 1800 UTC, and it rapidly strengthened to Category 3, becoming the first Eastern Pacific major hurricane since Hurricane Kenna
of the 2002 season
.
Shortly after peaking in intensity, Darby moved over coolers waters and began to deteriorate. The eye became less well-defined and the associated convection started weakening. Increasingly colder waters and growing wind shear
continued to affect Darby, and the cyclone weakened to a tropical storm on July 30. The low-level center of circulation became exposed from the thunderstorm activity, and the storm quickly degenerated into a swirl of clouds, although it maintained tropical storm strength. On July 31, it weakened to a tropical depression. Darby soon crossed into the Central Pacific Hurricane Center
's area of responsibility, and it dissipated as a tropical cyclone on August 1. However, its remnants continued westward under the low-level trade wind
s, and dropped heavy rainfall on Hawaii
several days after the cyclone dissipated.
, the remnants of Darby contributed to heavy rainfall and high winds, prompting the issuance of flash flood watch. Along the eastern shores of Kauai
, Oahu
, Molokai
, Maui
, and the Island of Hawaii, the system generated 4 to 8 ft (1.2 to 2.4 m) swells. The Honolulu Airport reported a daily record of 2.92 inches (74.2 mm) of rainfall, breaking the previous record of 0.96 inches (24.4 mm) set in 1948. Elsewhere, parts of Maui
reported in excess of 8 inches (203.2 mm) of precipitation, while 4.6 inches (116.8 mm) fell on Oahu
. The rainfall was beneficial in some areas, where dry conditions had persisted. Although crop damage from the storm system was limited, some farming operations were postponed and some coffee and not trees were damaged. Along the eastern shores of several Hawaiian Islands, the storm system triggered surf of 4 to 8 ft (1.2 to 2.4 m).
The heavy rainfall resulted in flash flooding throughout several areas. On Oahu, roads and some structures were flooded, and minor landslides were reported. On the island, telephone and electrical service were disrupted. At one location, a large boulder rolled down a hillside and struck a fire hydrant; firefighters were called to shut it off. On Kauai
, the Wailua River
exceeded flood stage on August 4. Small stream and drainage ditch flooding was reported in the Kau District of Hawaii. Excessive runoff around Kailua-Kona resulted in extensive flooding that forced the closure of five schools, submerged several roads, and triggered rockslides. Due to high water, several roads, including part of the Piilani Highway on Maui, were temporarily shut down. A portion of the Kamehameha Highway
was also closed after being submerged under waters of up to 1.5 foot (0.4572 m) deep. Despite the flooding, neither Darby nor its remnant moisture caused any casualties or severe property damage.
Pacific hurricane
A Pacific hurricane or tropical storm is a tropical cyclone that develops in the northeastern part of the Pacific Ocean. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern, , central , and western...
major hurricane since Hurricane Kenna
Hurricane Kenna
Hurricane Kenna was the second-most intense Pacific hurricane to strike the west coast of Mexico in recorded history. Kenna was the sixteenth tropical depression, thirteenth tropical storm, seventh hurricane, sixth major hurricane, and third Category 5 hurricane of the 2002 Pacific hurricane season...
in 2002
2002 Pacific hurricane season
The 2002 Pacific hurricane season was an event in tropical cyclone meteorology. The most notable storm that year was Hurricane Kenna, which reached Category 5 on the Saffir-Simpson Hurricane Scale. It made landfall near Puerto Vallarta, in the Mexican state of Jalisco, on October 25...
. The sixth tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
, fourth named storm, and second hurricane of the 2004 Pacific hurricane season
2004 Pacific hurricane season
The 2004 Pacific hurricane season officially started on May 15, 2004 in the eastern Pacific, and on June 1, 2004 in the central Pacific, and lasted until November 30, 2004...
, Darby developed from a tropical wave that emerged from the west coast of Africa on July 12. After crossing into the Eastern Pacific, the storm became a tropical depression on June 26. The system steadily intensified, and became a hurricane on 000 UTC July 28. Darby peaked as a Category 3 hurricane on the Saffir-Simpson Hurricane Scale
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
, though it quickly deteriorated due to cooler waters and increasing wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
. While Darby dissipated on August 1, the remnants of the tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
affected the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. The system produced high waves and heavy rainfall that led to extensive flash flooding. Numerous roads were closed, while minor landslides and rockslides were reported. Despite the effects, no fatalities or severe damages occurred.
Meteorological history
A tropical waveTropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
emerged from the west coast of Africa on July 12 and entered the Atlantic Ocean. The wave progressed westward, crossing the Atlantic and Caribbean Sea before crossing into the Eastern Pacific on July 20. The west began to exhibit signs of development on July 23. The next day, the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
(NHC) noted an associated area of showers and thunderstorms, indicating that gradual development
Tropical cyclogenesis
Tropical cyclogenesis is the term that describes the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which mid-latitude cyclogenesis occurs...
was possible. The system had become better organized and on July 25, the NHC continued to remark upon the potential for the weak low pressure area
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
—accompanied by disorganized convective activity—to develop. On July 26, the system became better-organized, and under favorable conditions it was upgraded to a tropical depression at 1200 UTC, while located about 760 miles (1,223.1 km) to the south-southwest of Cabo San Lucas, Mexico. Under the steering currents of a subtropical ridge of high pressure
High pressure area
A high-pressure area is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward due to the higher density air near their center and friction with land...
, the depression continued moving westward.
Upon becoming a tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
, the depression contained a somewhat well-defined low-level center of circulation
Eye (cyclone)
The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is a roughly circular area and typically 30–65 km in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the second most severe weather of a cyclone...
, as well as convective banding
Rainband
A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as...
. Based on Dvorak classifications, the storm was upgraded to a tropical storm at 0000 UTC on July 27; as the fourth tropical storm of the 2004 season
2004 Pacific hurricane season
The 2004 Pacific hurricane season officially started on May 15, 2004 in the eastern Pacific, and on June 1, 2004 in the central Pacific, and lasted until November 30, 2004...
, it was named Darby by the NHC. Darby continued to intensify, with established outflow
Outflow (meteorology)
Outflow, in meteorology, is air that flows outwards from a storm system. It is associated with ridging, or anticyclonic flow. In the low levels of the troposphere, outflow radiates from thunderstorms in the form of a wedge of rain-cooled air, which is visible as a thin rope-like cloud on weather...
and a well-defined banding feature. Later that day, forecasters predicted the storm to peak as a Category 1 hurricane on the Saffir-Simpson Hurricane Scale
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
. Darby was upgraded to a hurricane at 0000 UTC on July 28, at which time it began to turn towards the northwest. An eye
Eye (cyclone)
The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is a roughly circular area and typically 30–65 km in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the second most severe weather of a cyclone...
, embedded within the deep convection, developed later in the day. Darby attained Category 2 intensity at around 1800 UTC, and it rapidly strengthened to Category 3, becoming the first Eastern Pacific major hurricane since Hurricane Kenna
Hurricane Kenna
Hurricane Kenna was the second-most intense Pacific hurricane to strike the west coast of Mexico in recorded history. Kenna was the sixteenth tropical depression, thirteenth tropical storm, seventh hurricane, sixth major hurricane, and third Category 5 hurricane of the 2002 Pacific hurricane season...
of the 2002 season
2002 Pacific hurricane season
The 2002 Pacific hurricane season was an event in tropical cyclone meteorology. The most notable storm that year was Hurricane Kenna, which reached Category 5 on the Saffir-Simpson Hurricane Scale. It made landfall near Puerto Vallarta, in the Mexican state of Jalisco, on October 25...
.
Shortly after peaking in intensity, Darby moved over coolers waters and began to deteriorate. The eye became less well-defined and the associated convection started weakening. Increasingly colder waters and growing wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
continued to affect Darby, and the cyclone weakened to a tropical storm on July 30. The low-level center of circulation became exposed from the thunderstorm activity, and the storm quickly degenerated into a swirl of clouds, although it maintained tropical storm strength. On July 31, it weakened to a tropical depression. Darby soon crossed into the Central Pacific Hurricane Center
Central Pacific Hurricane Center
The Central Pacific Hurricane Center of the United States National Weather Service is the official body responsible for tracking and issuing tropical cyclone warnings, watches, advisories, discussions, and statements for the Central North Pacific Basin...
's area of responsibility, and it dissipated as a tropical cyclone on August 1. However, its remnants continued westward under the low-level trade wind
Trade wind
The trade winds are the prevailing pattern of easterly surface winds found in the tropics, within the lower portion of the Earth's atmosphere, in the lower section of the troposphere near the Earth's equator...
s, and dropped heavy rainfall on Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
several days after the cyclone dissipated.
Impact
Upon reaching the Hawaiian IslandsHawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
, the remnants of Darby contributed to heavy rainfall and high winds, prompting the issuance of flash flood watch. Along the eastern shores of Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
, Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
, Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
, Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, and the Island of Hawaii, the system generated 4 to 8 ft (1.2 to 2.4 m) swells. The Honolulu Airport reported a daily record of 2.92 inches (74.2 mm) of rainfall, breaking the previous record of 0.96 inches (24.4 mm) set in 1948. Elsewhere, parts of Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
reported in excess of 8 inches (203.2 mm) of precipitation, while 4.6 inches (116.8 mm) fell on Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
. The rainfall was beneficial in some areas, where dry conditions had persisted. Although crop damage from the storm system was limited, some farming operations were postponed and some coffee and not trees were damaged. Along the eastern shores of several Hawaiian Islands, the storm system triggered surf of 4 to 8 ft (1.2 to 2.4 m).
The heavy rainfall resulted in flash flooding throughout several areas. On Oahu, roads and some structures were flooded, and minor landslides were reported. On the island, telephone and electrical service were disrupted. At one location, a large boulder rolled down a hillside and struck a fire hydrant; firefighters were called to shut it off. On Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
, the Wailua River
Wailua River
The Wailuā River is a river on the island of Kauai in the U.S. state of Hawaii. It is formed by the confluence of its North and South forks just west of Wailua and enters the Pacific Ocean at . It is the only navigable river in the Hawaiian Islands...
exceeded flood stage on August 4. Small stream and drainage ditch flooding was reported in the Kau District of Hawaii. Excessive runoff around Kailua-Kona resulted in extensive flooding that forced the closure of five schools, submerged several roads, and triggered rockslides. Due to high water, several roads, including part of the Piilani Highway on Maui, were temporarily shut down. A portion of the Kamehameha Highway
Kamehameha Highway
Kamehameha Highway is one of the main highways serving suburban and rural O‘ahu in the U.S. state of Hawaii. Starting from Nimitz Highway near Pearl Harbor and Hickam Air Force Base in Honolulu, it serves the island's older western suburbs, turning north across the O‘ahu Central Valley to the...
was also closed after being submerged under waters of up to 1.5 foot (0.4572 m) deep. Despite the flooding, neither Darby nor its remnant moisture caused any casualties or severe property damage.
See also
- List of Hawaii hurricanes
- Other tropical cyclones named Darby
- Timeline of the 2004 Pacific hurricane seasonTimeline of the 2004 Pacific hurricane seasonThe 2004 Pacific hurricane season had 17 tropical cyclones, of which 12 became named storms, 6 became hurricanes, and 3 became major hurricanes . This timeline documents all the storm formations, strengthening, weakening, landfalls, extratropical transitions, as well as dissipation...