1998–99 South-West Indian Ocean cyclone season
Encyclopedia
The 1998–99 South-West Indian Ocean cyclone season was an annual event of tropical cyclone
formation. According to the Joint Typhoon Warning Center
it started on July 1, 1998 and ended on June 30, 1999. These dates conventionally delimit the period of each year when most tropical cyclones form in the basin, which is west of 90°E
and south of the Equator
. Tropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion
, which considered the season to run from August 1, 1998 through July 31, 1999.
on April 21. La Reunion decided to carry the system as F1, despite the fact that it was still a tropical storm.
, then the Sub-regional Tropical Cyclone Advisory Centre in Madagascar
assigns the appropriate name to the storm. If a tropical disturbance reaches moderate tropical storm status between 55°E
and 90°E
, then the Sub-regional Tropical Cyclone Advisory Centre in Mauritius
assigns the appropriate name to the storm. A new annual list is used every year so no names are retired.
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...
formation. According to the Joint Typhoon Warning Center
Joint Typhoon Warning Center
The Joint Typhoon Warning Center is a joint United States Navy – United States Air Force task force located at the Naval Maritime Forecast Center in Pearl Harbor, Hawaii...
it started on July 1, 1998 and ended on June 30, 1999. These dates conventionally delimit the period of each year when most tropical cyclones form in the basin, which is west of 90°E
90th meridian east
The meridian 90° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.The Ninety East Ridge is named after the meridian....
and south of the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
. Tropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion
Réunion
Réunion is a French island with a population of about 800,000 located in the Indian Ocean, east of Madagascar, about south west of Mauritius, the nearest island.Administratively, Réunion is one of the overseas departments of France...
, which considered the season to run from August 1, 1998 through July 31, 1999.
Tropical Depression H4
See Tropical Depression H4.Tropical Disturbance A1
This storm existed from September 3 until September 6. The minimum pressure was 1002 mb, and the mean winds only reached 25 knots (49 km/h).Tropical Disturbance A2
This system was also classified as Tropical Cyclone 02S by the Joint Typhoon Warning Center.Tropical Depression A4
This storm existed from January 4 until January 6. The minimum pressure was 996 mb, and the mean winds only reached 30 knots (58.8 km/h).Tropical Disturbance D1
This system was also classified as Tropical Cyclone 21S by the Joint Typhoon Warning Center.Tropical Disturbance D2/E1
This disturbance was classified as D2 by La Reunion. Once Cyclone Davina was named, it was reclassified as E1. This system was also classified as Tropical Cyclone 23S by the Joint Typhoon Warning Center.Tropical Disturbance E2
This was an exceptionally long-lived system that began in the Australian region and moved into La Reunion's area of responsibility on the 8th. La Reunion never considered the system as a tropical depression. This system was also classified as Tropical Cyclone 26S by the Joint Typhoon Warning Center.Tropical Depression E3
This system was also classified as Tropical Cyclone 29S by the Joint Typhoon Warning Center.Moderate Tropical Storm Hamish-F1
This system was formerly named "Hamish" by TCWC Perth, but rapidly dissipated once it crossed 90°E90th meridian east
The meridian 90° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.The Ninety East Ridge is named after the meridian....
on April 21. La Reunion decided to carry the system as F1, despite the fact that it was still a tropical storm.
Storm names
A tropical disturbance is named when it reaches moderate tropical storm strength. If a tropical disturbance reaches moderate tropical storm status west of 55°E55th meridian east
The meridian 55° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Europe, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole....
, then the Sub-regional Tropical Cyclone Advisory Centre in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
assigns the appropriate name to the storm. If a tropical disturbance reaches moderate tropical storm status between 55°E
55th meridian east
The meridian 55° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Europe, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole....
and 90°E
90th meridian east
The meridian 90° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.The Ninety East Ridge is named after the meridian....
, then the Sub-regional Tropical Cyclone Advisory Centre in Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
assigns the appropriate name to the storm. A new annual list is used every year so no names are retired.
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See also
- List of Southern Hemisphere tropical cyclone seasons
- Atlantic hurricane seasons: 19981998 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...
, 19991999 Atlantic hurricane seasonThe 1999 Atlantic hurricane season officially began on June 1, 1999, and lasted until November 30, 1999. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin.... - Pacific hurricane seasons: 19981998 Pacific hurricane seasonThe 1998 Pacific hurricane season was a moderately active Pacific hurricane season with seven tropical cyclones directly affecting land. The season officially started on May 15 in the eastern Pacific, and on June 1 in the central Pacific, and ended on November 30; these dates conventionally delimit...
, 19991999 Pacific hurricane seasonThe 1999 Pacific hurricane season officially started on May 15, 1999 in the eastern Pacific, and on June 1, 1999 in the central Pacific, and lasted until November 30, 1999. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific... - Pacific typhoon seasons: 19981998 Pacific typhoon seasonThe 1998 Pacific typhoon season has no official bounds, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November...
, 19991999 Pacific typhoon seasonThe 1999 Pacific typhoon season has no official bounds; it ran year-round in 1999, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November... - North Indian Ocean cyclone seasons: 19981998 North Indian Ocean cyclone seasonThe 1998 North Indian Ocean cyclone season was an active season in annual cycle of tropical cyclone formation. The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the...
, 19991999 North Indian Ocean cyclone seasonThe 1999 North Indian Ocean cyclone season was an event in the annual cycle of tropical cyclone formation. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with peaks in May and November...
External links
- Joint Typhoon Warning Center (JTWC).
- Météo France (RSMC La Réunion).
- World Meteorological Organization
- RA I Tropical Cyclone Committee Final Report
- Joint Typhoon Warning Center 1999 ATCR
- 1998-99 Best Track Data from Météo France
- July 1998 to June 1999 Tropical Cyclone Summaries and Operational Track Data
- Gary Padgett's Southern Hemisphere 1998-1999 Tropical Cyclone Season Review