1998–99 South-West Indian Ocean cyclone season

Infobox hurricane season
Basin=SWI
Year=1999
Track=1998-1999 South-West Indian Ocean cyclone season summary.jpg
First storm formed=July 20, 1998
Last storm dissipated=April 24, 1999
Strongest storm name=Evrina
Strongest storm pressure=925
Strongest storm winds=95
Average wind speed=10
Total depressions=9
Total storms=6 official, 5 unofficial
Total hurricanes=2
Total intense=
Fatalities=
Da

Inflated=
five seasons=1996–97, 1997–98, 1998–99, 1999–00, 2000–01The 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.

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torms

Tropical Depression H4 (01S)

Infobox Hurricane Small
Basin=SWI
Formed=July 20
Dissipated=July 25
10-min winds=30
1-min winds=35
Pressure=998The South Indian Ocean basin, the tropical cyclone season is considered to end on July 31 while the Joint Typhoon Warning Center (JTWC) considers it to begin on July 1. Therefore, RSMC La Reunion regarded this system as the last of the 1997-98 season, while the JTWC regarded it as the first of the 1998-99 season.

La Reunion issued the first advisory for this disturbance on July 20 while it was centered about 800 nautical miles east of Diego Garcia. For the next couple of days the system moved slowly toward the west-southwest. On July 22, it was upgraded to a tropical depression by La Reunion. Tropical Depression H4 was already weakening on the 23rd when the JTWC issued its first advisory, placing the center about 300 nm southeast of Diego Garcia. The system experienced considerable vertical wind shear throughout its life, but by July 23, the hostile conditions had abated somewhat. Given its proximity to Diego Garcia, the JTWC decided to initiate advisories on the system. cite web|author=Gary Padgett|year=1999|title=Monthly Global Tropical Cyclone Summary, July 1998|accessdate=2008-07-06|url=http://australiasevereweather.com/cyclones/1999/summ1998-99.htm] In post-operational analysis, the JTWC upgraded the system to a tropical storm on the 22nd.cite web|author=Joint Typhoon Warning Center|year=1999|title=Best Track for Cyclone 01S|accessdate=2008-07-06|url=http://metocph.nmci.navy.mil/jtwc/best_tracks/1999/1999s-bsh/bsh011999.txt]

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.

Tropical Disturbance A2 (02S)

Infobox Hurricane Small
Basin=SWI
Formed=September 29
Dissipated=October 2
10-min winds=25
1-min winds=35
Pressure=1002

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.

evere Tropical Storm Alda

Infobox Hurricane Small
Basin=SWI
Track=Alda 1999 track.pngFormed=January 16
Dissipated=January 19
10-min winds=52
1-min winds=65
Pressure=975

Moderate Tropical Storm Damien-Birenda

Infobox Hurricane Small
Basin=SWI
Track=Damien-Birenda 1999 track.pngFormed=January 28
Dissipated=February 2
10-min winds=35
1-min winds=50
Pressure=992

Moderate Tropical Storm Chikita

Infobox Hurricane Small
Basin=SWI
Track=Chikita 1999 track.pngFormed=January 31
Dissipated=February 4
10-min winds=35
1-min winds=40
Pressure=990

Tropical Disturbance D1 (21S)

Infobox Hurricane Small
Basin=SWI
Formed=February 11
Dissipated=February 16
10-min winds=33
1-min winds=45
Pressure=994

Tropical Disturbance D2/E1 (23S)

Infobox Hurricane Small
Basin=SWI
Formed=February 23
Dissipated=March 4
10-min winds=25
1-min winds=30
Pressure=1000This disturbance was classified as D2 by La Reunion. Once Cyclone Davina was named, it was reclassified as E1.

Intense Tropical Cyclone Davina

Infobox Hurricane Small
Basin=SWI
Track=Davina 1999 track.pngFormed=March 4
Dissipated=March 15
10-min winds=90
1-min winds=110
Pressure=930

Tropical Disturbance E2 (26S)

Infobox Hurricane Small
Basin=SWI
Formed=March 6
Dissipated=March 19
10-min winds=30
1-min winds=35
Pressure=999This 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.

Tropical Depression E3 (29S)

Infobox Hurricane Small
Basin=SWI
Formed=March 11
Dissipated=March 20
10-min winds=30
1-min winds=35
Pressure=995

Intense Tropical Cyclone Frederic-Evrina

Infobox Hurricane Small
Basin=SWI


Track=Frederic-Evrina 1999 track.pngFormed=March 31
Dissipated=April 8
10-min winds=95
1-min winds=125
Pressure=925

Moderate Tropical Storm Hamish-F1

Infobox Hurricane Small
Basin=SWI
Track=Hamish 1999 track.pngFormed=April 19
Dissipated=April 24
10-min winds=35
1-min winds=45
Pressure=992This system was formerly named "Hamish" by TCWC Perth, but rapidly dissipated once it crossed 90E on April 21. La Reunion decided to carry the system as F1, despite the fact that it was still a tropical storm.

torm 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°E, 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.http://www.wmo.ch/web/www/TCP/OperationPlans/TCP-12%2520Edition%25202006-English.pdf (PDF 461k)]

ee also

* List of Southern Hemisphere cyclone seasons
* Atlantic hurricane seasons: 1998, 1999
* Pacific hurricane seasons: 1998, 1999
* Pacific typhoon seasons: 1998, 1999
* North Indian Ocean cyclone seasons: 1998, 1999

References

External links

* [https://metocph.nmci.navy.mil/jtwc.html Joint Typhoon Warning Center (JTWC)] .
* [http://www.meteo.fr/temps/domtom/La_Reunion/ Météo France (RSMC La Réunion)] .
* [http://www.wmo.int/index-en.html World Meteorological Organization]
* [http://ftp.wmo.int/pages/prog/www/TCP_vO/Reports/RA1TCC14-Report.doc RA I Tropical Cyclone Committee Final Report]
* [http://metocph.nmci.navy.mil/jtwc/atcr/1999atcr/pdf.html Joint Typhoon Warning Center 1999 ATCR]
* [http://www.meteo.fr/temps/domtom/La_Reunion/base_cyclone/Saison/Saison_1999_1998.html 1998-99 Best Track Data from Météo France]
* [http://australiasevereweather.com/cyclones/tropical_cyclones_1999_summaries_and_track_data.htm July 1998 to June 1999 Tropical Cyclone Summaries and Operational Track Data]
* [http://australiasevereweather.com/cyclones/1999/summ1998-99.htm Gary Padgett's Southern Hemisphere 1998-1999 Tropical Cyclone Season Review]