1990–91 South Pacific cyclone season

1990–91 South Pacific cyclone season
First storm formed November 23, 1990
Last storm dissipated May 19, 1991
Strongest storm Sina – 965 hPa (mbar), 140 km/h (85 mph) (10-minute sustained)
Total depressions 5
Tropical cyclones 3
Severe tropical cyclones 1
Total fatalities None reported
Total damage $18.5 million (1991 USD)
South Pacific cyclone seasons
1988–89, 1989–90, 1990–91, 1991–92, 1992–93
Related articles

The 1990–91 South Pacific cyclone season was one of the least active cyclone seasons, with only three tropical cyclones occurring within the South Pacific to the east of 160°E. The season officially ran from November 1, 1990, to April 30, 1991 with the first disturbance of the season forming on November 23 and the last disturbance dissipating on May 19. This is the period of the year when most tropical cyclones form within the South Pacific Ocean. During the season there was no one killed from tropical disturbances whilst they were within the South Pacific. However six people were killed by Cyclone Joy when it made landfall on Australia. As a result of the impacts caused by Joy and Sina, the names were retired from the tropical cyclone naming lists.

During the season, tropical cyclones were monitored by the Tropical Cyclone Warning Centers (TCWC) in Nadi, Fiji, and in Wellington, New Zealand.[A 1] Whilst tropical cyclones that moved to the west of 160°E were monitored as a part of the Australian region by the TCWC in Brisbane Australia. Both the United States Joint Typhoon Warning Center (JTWC) and the Naval Western Oceanography Center (NWOC) issued unofficial warnings within the southern Pacific. The JTWC issued warnings between 160°E and the International Date Line whilst the NWOC issued warnings for tropical cyclones forming between the International Date Line and the coasts of the Americas. Both the JTWC and the NWOC designated tropical cyclones with a number and a P suffix with numbers assigned in order to tropical cyclones developing within the whole of the Southern Hemisphere. TCWC Nadi and TCWC Wellington both use the Australian Tropical Cyclone Intensity Scale, and measure windspeeds over a period of ten minutes, while the JTWC and the NWOC measured sustained winds over a period of one minute and use the Saffir–Simpson Hurricane Scale.

Contents

Seasonal summary


As a result of the South Pacific Convergence Zone being both weaker and located further to the north than in previous seasons and the Madden–Julian oscillations being weaker and less regular defined than in the previous two tropical cyclone seasons, only three tropical cyclones occurred within the South Pacific between 160°E and 120°W.[1][2] The first tropical cyclone developed as a tropical disturbance on November 20 before it was named Sina on November 24 as it intensified into a tropcial cyclone.[3] After peaking as a category three severe tropical cyclone on the Australian tropical cyclone intensity scale, Sina affected Fiji, Tonga, Niue and the Southern Cook Islands with total damage estimated at 18.5 million (1991 USD) before dissipating on December 4.[1][4] While looking back at the 1990-91 season, TCWC Nadi and TCWC Wellington, both identified a weak gale force tropical cyclone, that had affected Tonga between December 14–17.[5][6] On December 15, TCWC Nadi reported that a tropical depression had developed near the Solomon Islands.[4] Moving towards the east the depression went on to affect the Solomon Islands without causing any deaths or damage, before it moved into the Australian region on December 17.[1] The tropical depression was then named Joy by TCWC Brisbane on December 19, before it made landfall in Queensland on December 26.[1] The basin then remained quiet until March 15, when the JTWC reported that Tropical Depression 16P had moved into the basin.[1][7] Over the next couple of days the depression slowly intensified before peaking with 1-minute winds of 65 km/h (35 mph) early on March 18.[A 2][7] Moving towards the south the depression passed over New Caledonia on March 20 before dissipating the next day.[7] The final tropical cyclone of the season, Lisa, moved into the Southern Pacific on May 11 at its peak intensity of 110 km/h (75 mph).[1][4] During the next day as the storm moved towards the subtropical jet, Lisa rapidly weakened into a tropical depression before passing over Anatom Island without causing any serious damage or deaths.[1] After passing over Anatom, the depression weakened into an extratropical cyclone with it remnants tracked until May 20 when they dissipated to the east of New Zealand.[1][4] After the season both the names Sina and Joy were retired from the naming lists for the region.[8]

Storms

Severe Tropical Cyclone Sina

Category 3 severe tropical cyclone (Australian scale)
Category 4 tropical cyclone (SSHS)
Duration November 20 – December 4
Intensity 140 km/h (85 mph) (10-min),  960 mbar (hPa)

On November 20, TCWC Nadi reported that a tropical disturbance had formed to the west of Wallis Island.[3] Over the next couple of days the disturbance gradually developed and was classified as Tropical Depression 03P by the JTWC and TCWC Nadi on November 23.[3] During the next day the depression intensified into a tropcial cyclone and was subsequently named by TCWC Nadi as Sina at 1800 UTC, (0600 FST, November 25).[3] During November 25, Sina moved erratically around Rotuma before beginning to move slowly towards the south whilst gradually intensifying before early the next day it intensified into a severe tropical cyclone with hurricane force winds.[1] Later that day TCWC Nadi reported that Sina had peaked at 140 km/h (85 mph). The JTWC reported at this time that Sina was still intensifying before reporting that the windspeeds had peaked at 230 km/h (145 mph) early on November 27. During November 27 Sina moved around the southern edge of Viti Levu before passing over several of the smaller islands within the Fiji group of islands. The storm then continued to move towards the southeast whilst weakening passing close to the island of Tongatapu in Tonga and Niue. Sina eventually became extratropical on November 30 to the south of Niue before being absorbed by a trough of low pressure.

While it was active, Sina was responsible for FJ$33 million (US$18.5 million) in damage to Fiji, while no deaths and minor damage was reported within Tonga, Niue and the Southern Cook Islands. Within Fiji as there was no major flooding reported, it was assumed by TCWC Nadi that most of the damage had been done by the wind. On the western and southern coasts of Viti Levu, Sina's storm surge was responsible for some coastal erosion.

Tropical Depression Joy

Tropical depression (Australian scale)
Duration December 16 – December 17 Out of basin
Intensity 45 km/h (30 mph) (10-min),  998 mbar (hPa)

On December 15, in response to the formation of Typhoon Russ, in the North-Western Pacific ocean, a tropical area of low pressure formed about 500 km (300 mi), to the south-east of Honiara in the Solomon Islands.[1] During the next day the depression moved towards the east before it was classified as a tropical low by TCWC Nadi, before it moved into the Australian basin during December 17, where it was later named Joy.[1] While located within the basin, RSMC Nadi estimated 10-minute peak sustained windspeeds of 45 km/h (30 mph) and a peak pressure of 998 hPa (29.47 inHg).[4]

Tropical Depression 16P

Tropical depression (SSHS)
Duration March 15 – March 21
Intensity 55 km/h (35 mph) (1-min),  1000 mbar (hPa)

On March 15 the JTWC reported that Tropical Depression 16P, had moved into the Southern Pacific from the Australian region.[7] Over the next couple of days the depression moved slowly to the southeast, whilst gradually intensifying before it reached its peak 1-minute winds of 65 km/h (35 mph) early on March 18.[7] Moving towards the east the depression passed over New Caledonia on March 20 before dissipating the next day as it moved back into the Australian region.[7]

Tropical Cyclone Lisa

Category 2 tropical cyclone (Australian scale)
Tropical storm (SSHS)
Duration May 11 – May 19
Intensity 110 km/h (70 mph) (10-min),  975 mbar (hPa)

Early on May 11 TCWC Nadi, reported that Cyclone Lisa had moved into the South Pacific from the Australian basin at its 10-minute peak intensity of 110 km/h (75 mph).[1][4] During that day as Lisa moved towards the subtropical jet the cyclone rapidly weakened becoming a tropical depression during the next day.[1][4] Tropical Depression Lisa then passed over Anatom Island in Vanuatu and weakened into an extratropical depression, before primary warning responsibility for Lisa was passed to TCWC Wellington during May 13 as it moved to the south of 25S.[1][4] The Cyclone then began to deepen under an upper level mid latitude trough during May 14, before explosively regenerating early the next day reaching a secondary peak of 100 km/h (65 mph).[1][4] Lisa remnants were then tracked by TCWC Wellington until May 20 when they dissipated about 2600 km (1615 mi) to the east of Wellington, New Zealand.[1] There were no reports of any significant damage associated with Lisa.[1][9]

Season effects

This table lists all the storms that developed in the South Pacific to the east of longitude 160°E during the 1990–91 season. It includes their intensity on the Australian Tropical cyclone intensity scale, duration, name, landfalls, deaths, and damages. All data is taken from the warning centers from the region unless otherwise noted.

Storm
Name		 Dates active Storm category
at peak intensity		 Peak 10-min
sustained winds		 Pressure Areas affected Damage
(USD)		 Deaths Refs
Sina November 23 – December 4 Category 3 Severe Tropical Cyclone 140 km/h (85 mph) 960 hPa (28.35 inHg) Fiji, Niue, Tonga, Cook Islands &10000000018500000000000$18.5 million None [1]
None December 14 – 17 Category 1 Tropical Cyclone Unknown Unknown Tonga None None [6]
Joy December 15 – 17 Tropical Depression 55 km/h (30 mph) 998 hPa (29.47 inHg) Solomon Islands None None [1]
16P March 15 – 21 Tropical Depression 65 km/h (35 mph) 1000 hPa (29.53 inHg) New Caledonia None None [7]
Lisa May 11 – 19 Category 2 Tropical Cyclone 110 km/h (70 mph) 975 hPa (28.79 inHg) Vanuatu None None [1][9]
Season Aggregates
5 disturbances November 23 – May 19 140 km/h (85 mph) 960 hPa (28.35 inHg) &10000000018500000000000$18.5 million None

See also

Notes

  1. ^ TCWC Nadi warned on systems in the South Pacific located from the Equator to 25°S and from 160°E to 120°W. TCWC Wellington warns on systems from 25°S to 40°S and from 160°E to 120°W
  2. ^ The figures for maximum sustained winds and position estimates are rounded to the nearest 5 units (knots, miles, or kilometers), following the convention used in the Fiji Meteorological Service's operational products for each storm. All other units are rounded to the nearest digit.

References

  1. ^ a b c d e f g h i j k l m n o p q r s t Bannister, A.J.; Smith, K. J. (1993-12-04). "The South Pacific and Southeast Indian Ocean Tropical Cyclone Season 1990–1991". Australian Meteorological Magazine (Bureau of Meteorology) 42: 111–121. http://www.bom.gov.au/amm/docs/1993/bannister.pdf. Retrieved 2010-06-16. 
  2. ^ Prasad, Vikash; Koop, Neville Louis (2003). "4.4". In Zschau. Jochen; Küppers. Andreas, N.. Early warning systems for natural disaster reduction — The Tropical Cyclone Warning System in the Southwest Pacific. Springer. pp. 185. ISBN 3-540-67962-6. http://books.google.com/books?id=De3JAP1N_wEC. Retrieved 2011-02-27. 
  3. ^ a b c d Ward Graham F.A. (1995-03-01). "Prediction of tropical cyclone formation in terms of sea-surface temperatures vorticity and vertical windshear". Australian meteorological magazine (Australian Bureau of Meteorology) 44. http://www.bom.gov.au/amoj/docs/1995/ward.pdf. Retrieved 2010-06-16. 
  4. ^ a b c d e f g h i Unattributed (2009-05-22). "TCWC Wellington Best Track Data 1967–2006". Fiji Meteorological Service, Meteorological Service of New Zealand Limited, Bureau of Meteorology. National Oceanic and Atmospheric Administration. ftp://eclipse.ncdc.noaa.gov/pub/ibtracs/original-bt-data-files/wellington/TC_BT_1967_2006.xls. Retrieved 2010-06-16. 
  5. ^ Unattributed (2005-07-21). "The Kingdom of Tonga’s Initial National Communication In response to its commitments under the United Nations Framework Convention on Climate Change". The Government of Tonga. pp. 12–13. http://unfccc.int/resource/docs/natc/tonnc1.pdf. Retrieved 2011-07-07. 
  6. ^ a b Terry, James P. (2007). "Appendix 1". Tropical cyclones: climatology and impacts in the South Pacific. Springer. pp. 188–191. ISBN 978-0-387-71542-1. http://books.google.com/?id=syqPSpliRCwC&pg=PA194&dq=Cyclone+Vania#v=onepage&q=Cyclone%20Vania&f=false. Retrieved 2011-05-15. 
  7. ^ a b c d e f g "Tropical Depression 16P best track analysis". Joint Typhoon Warning Center. 1992. http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/best_tracks/1991/1991s-bsh/bsh161991.txt. Retrieved 2010-06-16. 
  8. ^ Unattributed (2009-03-10). "Tropical Cyclone Operational Plan for the South Pacific and South-East Indian Ocean" (2008 ed.). World Meteorological Organization. Archived from the original on 2009-05-21. http://www.webcitation.org/query?id=1242952602408859. Retrieved 2010-06-16. 
  9. ^ a b Unattributed (2010-03-13). "Tropical cyclones in Vanuatu: 1847 to 1994". Vanuatu Meteorological Service. Pacific Disaster Net. Archived from the original on 2010-11-18. http://www.webcitation.org/5uJzQPW0U. Retrieved 2010-03-13. 

External links

Tropical cyclones of the 1990–91 South Pacific cyclone season
South Pacific Tropical Cyclone Scale
TDI TDE 1 2 3 4 5
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