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Hurricane Karl (1998)
Encyclopedia
Hurricane Karl was one of four active hurricanes in the Atlantic Ocean
on September 26, 1998. The 11th tropical cyclone and named storm of the 1998 Atlantic hurricane season
, Karl developed from a non-tropical low pressure system that was noted off the coast of the Carolinas. The low became better organized in convection
, and it was declared a tropical depression on September 23; it became a hurricane shortly thereafter. A small storm, Karl initially tracked towards the east before turning east-southeastward. The hurricane peaked as a Category 2 hurricane on the Saffir-Simpson Hurricane Scale
, and by September 26 it accelerated towards the northeast. Increased wind shear
caused the storm to weaken, and it transitioned into an extratropical cyclone
on September 28. As a tropical cyclone, Karl remained away from land; no effects or damages were reported.
. Initially, it was believed that Karl may have been related to the remnants of Tropical Storm Hermine
, though this was not later confirmed. Upon forming, the depression was the tenth tropical cyclone to form within the Atlantic in 35 days. In advance of a frontal boundary
moving off the U.S. East Coast, the depression was moving quickly towards the east. Satellite imagery suggested that the center of circulation was situated beneath the deep convection; convective banding increased, and later on September 23, the depression was upgraded to Tropical Storm Karl. At the time, the storm began tracking towards the east-southeast.
A small hurricane, Karl slowed in forward motion early on September 24 while it gradually intensified. By later that day, Karl was located in a region with westerly and northwesterly wind shear
, which left the center partially exposed from the convective activity. However, a symmetrical cloud pattern began to gradually form, and Karl was upgraded to a hurricane at 1200 UTC; minimal hurricane intensity was forecast to be maintained for 24 hours before weakening due to increased wind shear.
In response to a large mid- to upper-level trough
, Karl accelerated towards the northeast. Late on September 26, a small, well-defined eye
formed, and the storm reached its peak intensity of 105 mph (165 km/h) as a Category 2 hurricane on the Saffir-Simpson Hurricane Scale
at 0000 UTC on September 27. The eye remained distinct for about six hours, before the storm began to weaken due to wind shear. Karl remained a compact storm, and satellite imagery indicated that the cyclone began to lose tropical characteristics. Deep convective activity was limited to the north and northwest of the center, and the low-level center became separated from the center of the cloud circulation. Karl weakened to a tropical storm at 0000 UTC on September 28, while located to the west-northwest of the Azores
. Later that day, the storm became extratropical
over cooler waters, when the center of circulation became separated from the deep convection. The extratropical remnants were tracked south of Ireland
on September 29.
was over the Straits of Florida
, Hurricane Ivan was in the North Atlantic, and Hurricane Jeanne was located between Africa
and the Lesser Antilles
. As such, Karl was one of four simultaneously active hurricanes in the Atlantic, the first such occurrence since August 22, 1893. However, three hurricanes also co-existed in the Atlantic on September 11, 1961, with a possible fourth. Because Karl remained away from land as a tropical cyclone, no effects, property damage or fatalities were reported; no ships were affected, and no tropical cyclone warnings and watches
were issued.
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
on September 26, 1998. The 11th tropical cyclone and named storm of the 1998 Atlantic hurricane season
1998 Atlantic hurricane season
The 1998 Atlantic hurricane season officially began on June 1, 1998, and lasted until November 30, 1998. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin; however, the season extended through December 1 as Hurricane Nicole remained...
, Karl developed from a non-tropical low pressure system that was noted off the coast of the Carolinas. The low became better organized in convection
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
, and it was declared a tropical depression on September 23; it became a hurricane shortly thereafter. A small storm, Karl initially tracked towards the east before turning east-southeastward. The hurricane peaked as a Category 2 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...
, and by September 26 it accelerated towards the northeast. Increased 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...
caused the storm to weaken, and it transitioned into an 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...
on September 28. As a tropical cyclone, Karl remained away from land; no effects or damages were reported.
Meteorological history
The origins of Hurricane Karl were in a small non-tropical low pressure system that was first noted on the coast of the Carolinas on September 21. Deep convection became better organized, and on September 23, the system was designated a tropical depression while located to the west-northwest of BermudaBermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
. Initially, it was believed that Karl may have been related to the remnants of Tropical Storm Hermine
Tropical Storm Hermine (1998)
Tropical Storm Hermine was the eighth tropical cyclone and named storm of the 1998 Atlantic hurricane season. Hermine developed from a tropical wave that emerged from the west coast of Africa on September 5. The wave moved westward across the Atlantic Ocean, and on entering the northwest Caribbean...
, though this was not later confirmed. Upon forming, the depression was the tenth tropical cyclone to form within the Atlantic in 35 days. In advance of a frontal boundary
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...
moving off the U.S. East Coast, the depression was moving quickly towards the east. Satellite imagery suggested that the center of circulation was situated beneath the deep convection; convective banding increased, and later on September 23, the depression was upgraded to Tropical Storm Karl. At the time, the storm began tracking towards the east-southeast.
A small hurricane, Karl slowed in forward motion early on September 24 while it gradually intensified. By later that day, Karl was located in a region with westerly and northwesterly 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...
, which left the center partially exposed from the convective activity. However, a symmetrical cloud pattern began to gradually form, and Karl was upgraded to a hurricane at 1200 UTC; minimal hurricane intensity was forecast to be maintained for 24 hours before weakening due to increased wind shear.
In response to a large mid- to upper-level trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
, Karl accelerated towards the northeast. Late on September 26, a small, well-defined 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...
formed, and the storm reached its peak intensity of 105 mph (165 km/h) as a Category 2 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...
at 0000 UTC on September 27. The eye remained distinct for about six hours, before the storm began to weaken due to wind shear. Karl remained a compact storm, and satellite imagery indicated that the cyclone began to lose tropical characteristics. Deep convective activity was limited to the north and northwest of the center, and the low-level center became separated from the center of the cloud circulation. Karl weakened to a tropical storm at 0000 UTC on September 28, while located to the west-northwest of the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
. Later that day, the storm became extratropical
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...
over cooler waters, when the center of circulation became separated from the deep convection. The extratropical remnants were tracked south of Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
on September 29.
Impact and records
On September 26, Hurricane GeorgesHurricane Georges
Hurricane Georges was a very destructive, powerful and long-lived Cape Verde-type Category 4 hurricane. Georges was the seventh tropical storm, fourth hurricane, and second major hurricane of the 1998 Atlantic hurricane season...
was over the Straits of Florida
Straits of Florida
The Straits of Florida, Florida Straits, or Florida Strait is a strait located south-southeast of the North American mainland, generally accepted to be between the Gulf of Mexico and the Atlantic Ocean, and between the Florida Keys and Cuba. The strait carries the Florida Current, the beginning of...
, Hurricane Ivan was in the North Atlantic, and Hurricane Jeanne was located between Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and the Lesser Antilles
Lesser Antilles
The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...
. As such, Karl was one of four simultaneously active hurricanes in the Atlantic, the first such occurrence since August 22, 1893. However, three hurricanes also co-existed in the Atlantic on September 11, 1961, with a possible fourth. Because Karl remained away from land as a tropical cyclone, no effects, property damage or fatalities were reported; no ships were affected, and no tropical cyclone warnings and watches
Tropical cyclone warnings and watches
Warnings and watches are two levels of alert issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate...
were issued.
See also
- List of Atlantic hurricanes
- 1998 Atlantic hurricane season1998 Atlantic hurricane seasonThe 1998 Atlantic hurricane season officially began on June 1, 1998, and lasted until November 30, 1998. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin; however, the season extended through December 1 as Hurricane Nicole remained...
- Tropical cycloneTropical cycloneA 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...
- Extratropical cycloneExtratropical cycloneExtratropical 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...