Kona storm
Encyclopedia
Kona storms are a type of seasonal cyclone
in the Hawaiian Islands
, usually formed in the winter from winds coming from the westerly "kona" (normally leeward) direction. They are mainly cold core cyclones, which places them in the extratropical cyclone
rather than the subtropical cyclone
category. Hawaii typically experiences two to three annually, which can affect the state for a week or more. Among their hazards are heavy rain
, hail
storms, flash flood
s and their associated landslide
s, high winds which result in large surf and swells
, and waterspout
s.
term (related to similar words in other Polynesian
languages) for the western (to southwestern) side of an island.
The Kona District
for example on the Big Island of Hawaii
still uses this name.
Although normally dry and leeward,
the traditional easterly (to northeasterly) tradewind
s slacken and reverse during one of these cyclones.
s, a definition change in the term during the early 1970s makes categorization of the systems not straightforward. Kona lows are typically cold core, making them extratropical cyclone
s. However, they generally share the subtropical cyclone characteristic of losing their associated weather fronts with time, since the cyclones tend to retrograde slowly.
Otkin and Martin identified three types of kona storms: cold-frontal cyclogenesis cyclones (CFCs), trade wind easterlies, and cold-frontal cyclogenesis/trade wind easterlies cyclones. Of the three, CFC cyclones are the most common.
Rainfall in a Kona storm is more pronounced than a cold front storm
, and most intense from south to east of the storm and in front of the storm's center. Steady rains may last from several hours to days, with longer lasting storms typically interrupted by intervals of lighter rain and partial clearing. Intense showers may appear on more moderate but steady rain.
Hawaii typically experiences two to three annually between October and April. The cyclone events for Hawaii can be long-lived, affecting the state for a week or more. Kona lows produce a wide range of weather hazards for Hawaii. Among them are heavy rain, hailstorms, flash floods and their associated landslides, high winds which result in large surf and swells, waterspouts, and heavy snows on the higher mountains.
In December of 2008, lightning strikes from a Kona storm caused the entire power grid of the island of Oahu to black out, while then President-elect, Barack Obama
was visiting.
is entitled "The Kona Winds."
Cyclone
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale...
in 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...
, usually formed in the winter from winds coming from the westerly "kona" (normally leeward) direction. They are mainly cold core cyclones, which places them in the extratropical cyclone
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
rather than the subtropical cyclone
Subtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
category. Hawaii typically experiences two to three annually, which can affect the state for a week or more. Among their hazards are heavy rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
, hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
storms, flash flood
Flash flood
A flash flood is a rapid flooding of geomorphic low-lying areas—washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a storm, hurricane, or tropical storm or meltwater from ice or snow flowing over ice sheets or snowfields...
s and their associated landslide
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...
s, high winds which result in large surf and swells
Swell (ocean)
A swell, in the context of an ocean, sea or lake, is a series surface gravity waves that is not generated by the local wind. Swell waves often have a long wavelength but this varies with the size of the water body, e.g. rarely more than 150 m in the Mediterranean, and from event to event, with...
, and waterspout
Waterspout
A waterspout is an intense columnar vortex that occurs over a body of water and is connected to a cumuliform cloud. In the common form, it is a non-supercell tornado over water. While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur...
s.
Origin of term
Kona is a Hawaiian languageHawaiian language
The Hawaiian language is a Polynesian language that takes its name from Hawaii, the largest island in the tropical North Pacific archipelago where it developed. Hawaiian, along with English, is an official language of the state of Hawaii...
term (related to similar words in other Polynesian
Polynesian languages
The Polynesian languages are a language family spoken in the region known as Polynesia. They are classified as part of the Austronesian family, belonging to the Oceanic branch of that family. They fall into two branches: Tongic and Nuclear Polynesian. Polynesians share many cultural traits...
languages) for the western (to southwestern) side of an island.
The Kona District
Kona District, Hawaii
Kona is the name of a moku or district on the Big Island of Hawaii in the State of Hawaii. In the current system of administration of Hawaii County, the moku of Kona is divided into North Kona District and South Kona District . The term "Kona" is sometimes used to refer to its largest town,...
for example on the Big Island of Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
still uses this name.
Although normally dry and leeward,
the traditional easterly (to northeasterly) tradewind
Tradewind
A trade wind is a wind pattern. Trade Wind or Tradewind can also refer to:* Trade Winds, 1938 film directed by Tay Garnett* Trade Wind, alternate name for the 1998 film At Sachem Farm* Trade Wind, a book by M. M...
s slacken and reverse during one of these cyclones.
Character of the cyclones
Once termed as subtropical cycloneSubtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
s, a definition change in the term during the early 1970s makes categorization of the systems not straightforward. Kona lows are typically cold core, making them extratropical cyclone
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
s. However, they generally share the subtropical cyclone characteristic of losing their associated weather fronts with time, since the cyclones tend to retrograde slowly.
Otkin and Martin identified three types of kona storms: cold-frontal cyclogenesis cyclones (CFCs), trade wind easterlies, and cold-frontal cyclogenesis/trade wind easterlies cyclones. Of the three, CFC cyclones are the most common.
Rainfall in a Kona storm is more pronounced than a cold front storm
Surface weather analysis
Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations...
, and most intense from south to east of the storm and in front of the storm's center. Steady rains may last from several hours to days, with longer lasting storms typically interrupted by intervals of lighter rain and partial clearing. Intense showers may appear on more moderate but steady rain.
Frequency and effects
Some winters occur without a single Kona storm, with a high of four or five.Hawaii typically experiences two to three annually between October and April. The cyclone events for Hawaii can be long-lived, affecting the state for a week or more. Kona lows produce a wide range of weather hazards for Hawaii. Among them are heavy rain, hailstorms, flash floods and their associated landslides, high winds which result in large surf and swells, waterspouts, and heavy snows on the higher mountains.
Kona winds
Kona winds are associated with cyclones with central pressures below 1000 hPa which pass within 500 miles/820 km northwest of the Hawaiian Islands. Strong Kona winds usually last for a day. Considerable damage is caused to boats lying southwest of the islands. On land, trees are uprooted and roofs can be blown off homes. When passing through mountain gaps and over mountains, downsloped winds gust over 100 mph/165 km/h, which causes much of the destruction.Examples
The most powerful Kona storm in the last fifty years struck the Hawaiian islands between 8 January and 11 January 1980. The low pressure primarily responsible for the severe conditions had a barometric pressure of 975mb on January 8th, while passing north of the state, one of the lowest pressure readings ever recorded in Hawaiian waters as a result of an extratropical storm. The storm caused severe weather across the entire state, forcing the closure of all airports. Rainfall from the storm was extremely heavy, surpassing twenty inches in many locations, particularly on the Big Island and Maui. High surf from the storm caused extensive damage, particularly along the Kona coast of the Big Island, where the towns of Kailua-Kona and Puako received extensive damage. Winds from the storm averaged around 40-50 mph on the open ocean, but varied tremendously on land due to unique geographic features. Some areas experienced wind gusts well over hurricane force, including a low altitude gust of 106 mi/h on Lahaina Roads, Maui. Haiku, on the windward coast of Maui, experienced a wind gust of 75 mi/h. On the high mountain summits of the Big Island and Maui, winds of over 110 mi/h were recorded. Damage from the storm was estimated at between $25 and 35 million (in 1980 dollars).In December of 2008, lightning strikes from a Kona storm caused the entire power grid of the island of Oahu to black out, while then President-elect, Barack Obama
Barack Obama
Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...
was visiting.
In Popular Culture
The fourth episode of the sixth season of Magnum, P.I.Magnum, P.I.
Magnum, P.I. is an American television series starring Tom Selleck as Thomas Magnum, a private investigator living on Oahu, Hawaii. The series ran from 1980 to 1988 in first-run broadcast on the American CBS television network....
is entitled "The Kona Winds."