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Hurricane Karl (2004)
Encyclopedia
Hurricane Karl was a powerful Cape Verde-type hurricane
during the 2004 Atlantic hurricane season
. It was the eleventh named storm
, eighth hurricane and sixth major hurricane of the 2004 season. Karl formed on September 16, originating from a strong tropical wave
that emerged off of Africa. It rapidly intensified, becoming a major hurricane on two occasions. Karl peaked as a strong Category 4 hurricane on the Saffir-Simpson hurricane scale
on September 21 with 145 mph (230 km/h) winds. It weakened as it moved northward, becoming extratropical on September 24 in the north Atlantic and becoming absorbed by another system on September 28. The extratropical storm affected the Faroe Islands
, but no damage was reported there and no lives were lost.
islands on the morning of September 16, as it headed westward in the open tropical Atlantic following the periphery of the subtropical ridge
. That afternoon, the depression continued to rapidly organize and was upgraded to Tropical Storm Karl. Due to healthy outflow around an upper-level anticyclone
over Karl and a favorable environment with the warmest sea surface temperatures of the year, rapid deepening
began on the evening of September 17, with the storm developing a small eye
and being upgraded to Hurricane Karl. With water around 28°C (83°F) and low wind shear
, the cyclone continued to rapidly intensify on the morning of September 18. The intensity leveled off somewhat that afternoon as a strong Category 2 hurricane with winds of 110 mph (175 km/h).
Late in the evening of September 18, Karl attained Category 3 status, becoming the sixth major hurricane of 2004. On September 19, Karl continued to strengthen, maintaining a well-defined eye, and strengthening late that day into a Category 4 hurricane with winds of 135 mph (215 km/h) and a minimum pressure of 948 mbar. Early on September 20, the storm weakened slightly as a result of an eyewall replacement cycle
, weakening back to a strong Category 3 hurricane. At this time Karl began to turn sharply northward into a weakness in the subtropical ridge.
After intensification stopped on September 20 due to the eyewall cycle and slightly increased wind shear, Karl quickly restrengthened that evening over very warm water, and early on September 21 reached its peak intensity as a powerful Category 4 hurricane with 145 mph (230 km/h) winds and a minimum central pressure of 938 mbar. That morning, as Karl was moving northward, another eyewall replacement cycle began to take place and vertical shear increased, again weakening the storm temporarily. The trend continued into the evening, and the storm weakened to a Category 2 hurricane by early on September 22. The weakening trend slowed down and eventually leveled off that afternoon with Karl remaining a Category 2 hurricane as the storm turned towards the north-northeast. Late that evening, Karl began to restrengthen once again as wind shear diminished. The intensification continued into the morning of September 23, as Karl became a major hurricane a second time, reaching a final peak of 125 mph (205 km/h) winds. Cooler waters and increased shear soon prevailed, however, and the storm quickly weakened, dropping to a Category 1 hurricane by late that evening as the low-level circulation became detached from the mid-level circulation due to the strong southwesterly vertical wind shear
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Early on September 24, Karl continued its north-northeast track over the open north-central Atlantic and continued to gradually weaken. It started to come in contact with the baroclinic zone and began to lose tropical characteristics, while still a Category 1 hurricane. Karl became extratropical shortly afterward over the northern Atlantic at about 47°N, with its winds dropping below hurricane strength shortly thereafter. The extratropical storm made landfall on the Faroe Islands
with hurricane-force wind gusts. As an extratropical low, the cyclone moved northeastward and eastward across the North Atlantic Ocean and the North Sea
, eventually reaching Norway before it was absorbed into another extratropical low late on September 28.
as an extratropical storm with sustained winds near 70 mph (110 km/h) and with wind gusts up to 89 mph (144 km/h). No damages or deaths were reported, and no ships came directly into contact with Karl; the strongest winds reported were from the ship Rotterdam, which reported 52 mph (83 km/h) sustained winds in the north Atlantic while Karl was a Category 1 storm in extratropical transition.
Cape Verde-type hurricane
A Cape Verde-type hurricane is an Atlantic hurricane that develops near the Cape Verde islands, off the west coast of Africa. The average hurricane season has about two Cape Verde-type hurricanes, which are usually the largest and most intense storms of the season because they often have plenty of...
during the 2004 Atlantic hurricane season
2004 Atlantic hurricane season
The 2004 Atlantic hurricane season officially began on June 1, 2004, and lasted until November 30, 2004. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin...
. It was the eleventh named storm
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...
, eighth hurricane and sixth major hurricane of the 2004 season. Karl formed on September 16, originating from a strong tropical wave
Tropical 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...
that emerged off of Africa. It rapidly intensified, becoming a major hurricane on two occasions. Karl peaked as a strong Category 4 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...
on September 21 with 145 mph (230 km/h) winds. It weakened as it moved northward, becoming extratropical on September 24 in the north Atlantic and becoming absorbed by another system on September 28. The extratropical storm affected the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
, but no damage was reported there and no lives were lost.
Meteorological history
Karl originated in a strong tropical wave that moved off the coast of Africa on September 13. The wave gradually became better organized, and it was declared Tropical Depression Twelve about 670 miles (1,080 km) west-southwest of the Cape VerdeCape Verde
The Republic of Cape Verde is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa...
islands on the morning of September 16, as it headed westward in the open tropical Atlantic following the periphery of the subtropical ridge
Subtropical ridge
The subtropical ridge is a significant belt of high pressure situated around the latitudes of 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. It is characterized by mostly calm winds, which acts to reduce air quality under its axis by causing fog overnight, and haze during...
. That afternoon, the depression continued to rapidly organize and was upgraded to Tropical Storm Karl. Due to healthy outflow around an upper-level anticyclone
Anticyclone
An anticyclone is a weather phenomenon defined by the United States' National Weather Service's glossary as "[a] large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere"...
over Karl and a favorable environment with the warmest sea surface temperatures of the year, rapid deepening
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...
began on the evening of September 17, with the storm developing a small 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...
and being upgraded to Hurricane Karl. With water around 28°C (83°F) and low 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...
, the cyclone continued to rapidly intensify on the morning of September 18. The intensity leveled off somewhat that afternoon as a strong Category 2 hurricane with winds of 110 mph (175 km/h).
Late in the evening of September 18, Karl attained Category 3 status, becoming the sixth major hurricane of 2004. On September 19, Karl continued to strengthen, maintaining a well-defined eye, and strengthening late that day into a Category 4 hurricane with winds of 135 mph (215 km/h) and a minimum pressure of 948 mbar. Early on September 20, the storm weakened slightly as a result of an eyewall replacement cycle
Eyewall replacement cycle
Eyewall replacement cycles, also called concentric eyewall cycles, naturally occur in intense tropical cyclones, generally with winds greater than 185 km/h , or major hurricanes...
, weakening back to a strong Category 3 hurricane. At this time Karl began to turn sharply northward into a weakness in the subtropical ridge.
After intensification stopped on September 20 due to the eyewall cycle and slightly increased wind shear, Karl quickly restrengthened that evening over very warm water, and early on September 21 reached its peak intensity as a powerful Category 4 hurricane with 145 mph (230 km/h) winds and a minimum central pressure of 938 mbar. That morning, as Karl was moving northward, another eyewall replacement cycle began to take place and vertical shear increased, again weakening the storm temporarily. The trend continued into the evening, and the storm weakened to a Category 2 hurricane by early on September 22. The weakening trend slowed down and eventually leveled off that afternoon with Karl remaining a Category 2 hurricane as the storm turned towards the north-northeast. Late that evening, Karl began to restrengthen once again as wind shear diminished. The intensification continued into the morning of September 23, as Karl became a major hurricane a second time, reaching a final peak of 125 mph (205 km/h) winds. Cooler waters and increased shear soon prevailed, however, and the storm quickly weakened, dropping to a Category 1 hurricane by late that evening as the low-level circulation became detached from the mid-level circulation due to the strong southwesterly vertical 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...
.
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
with hurricane-force wind gusts. As an extratropical low, the cyclone moved northeastward and eastward across the North Atlantic Ocean and the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
, eventually reaching Norway before it was absorbed into another extratropical low late on September 28.
Impact
Karl made landfall in the Faroe IslandsFaroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
as an extratropical storm with sustained winds near 70 mph (110 km/h) and with wind gusts up to 89 mph (144 km/h). No damages or deaths were reported, and no ships came directly into contact with Karl; the strongest winds reported were from the ship Rotterdam, which reported 52 mph (83 km/h) sustained winds in the north Atlantic while Karl was a Category 1 storm in extratropical transition.
See also
- Other storms named Karl
External links
- NHC's Tropical Cyclone Report on Hurricane Karl