2019–20 South Pacific cyclone season

The 2019–20 South Pacific cyclone season is the period of the year when most tropical cyclones form within the South Pacific Ocean to the east of 160°E. The season officially runs from November 1, 2019 to April 30, 2020, however a tropical cyclone could form at any time between July 1, 2019 and June 30, 2020 and would count towards the season total. During the season, tropical cyclones will be officially monitored by the Regional Specialized Meteorological Center (RSMC) in Nadi, Fiji and the Tropical Cyclone Warning Centers in Brisbane, Australia and Wellington, New Zealand. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) will also monitor the basin and issue unofficial warnings for American interests. RSMC Nadi attaches a number and an F suffix to tropical disturbances that form in or move into the basin while the JTWC designates significant tropical cyclones with a number and a P suffix. RSMC Nadi, TCWC Wellington and TCWC Brisbane all use the Australian Tropical Cyclone Intensity Scale and estimate windspeeds over a period of ten minutes, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

2019–20 South Pacific cyclone season
Season summary map
Seasonal boundaries
First system formedNovember 22, 2019
Last system dissipatedSeason ongoing
Strongest storm
NameRita
  Maximum winds120 km/h (75 mph)
(10-minute sustained)
  Lowest pressure977 hPa (mbar)
Seasonal statistics
Total disturbances1
Total depressions1
Tropical cyclones1
Severe tropical cyclones1
Total fatalitiesNone
Total damageNone
Related articles

Seasonal forecasts

Source/Record Tropical
Cyclone
Severe
Tropical Cyclone
Ref
Record high:1997–98: 161982–83: 10[1]
Record low:1990–91:  22008–09:  0[1]
Average (1969-70 - 2018-19):7.1 [2]
NIWA October9-124[3]
Fiji Meteorological Service5-82-4[2]
Region Chance of
above average
Average
number
Actual
activity
Western South Pacific
(142.5°E—165°E; includes Australian basin)
54% 4 0
Eastern South Pacific
(165°E—120°W)
41% 7 1
Source:BOM's South Pacific Tropical Cyclone Season Outlook[4]

Ahead of the cyclone season formally starting, the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM), New Zealand's MetService and National Institute of Water and Atmospheric Research (NIWA) and various other Pacific Meteorological services, all contributed towards the Island Climate Update tropical cyclone outlook that was released during October 2019.[3] The outlook took into account the ENSO neutral conditions that had been observed across the Pacific and analog seasons, that had ENSO neutral and El Nino conditions occurring during the season.[3] The outlook called for a near-average number of tropical cyclones for the 2019–20 season, with nine to twelve named tropical cyclones, predicted to occur between 135°E and 120°W, compared to an average of just over 10.[3] At least four of the tropical cyclones were expected to intensify further and become severe tropical cyclones, while it was noted that a Category 5 severe tropical cyclone could occur during the season.[3]

In addition to contributing towards the Island Climate Update outlook, the FMS and the BoM issued their own seasonal forecasts for the South Pacific region.[2][4] The BoM issued two seasonal forecasts for the Southern Pacific Ocean, for their self-defined eastern and western regions of the South Pacific Ocean.[4] They predicted that the Western region between 142.5°E and 165°E, had a 54% chance of seeing activity above its average of 4 tropical cyclones. The BoM also predicted that the Eastern Region between 165°E and 120°W, had a 41% chance of seeing activity above its average of 7 tropical cyclones.[4] Within their outlook the FMS predicted that between five and eight tropical cyclones, would occur within the basin compared to an average of around 7.1 cyclones.[2] At least two of the tropical cyclones were expected to intensify further and become Category 3 or higher severe tropical cyclones.[2]

Both the Island Climate Update and the FMS tropical cyclone outlooks assessed the risk of a tropical cyclone affecting a certain island or territory.[2][3] The Island Climate Update Outlook predicted that American Samoa, French Polynesia's Austral Islands, Niue, Samoa, Tonga, Tuvalu as well as the Solomon Islands and Southern Cook Islands had an elevated chance, while the Wallis and Futuna had a normal to elevated chance of being impacted by a tropical cyclone.[3] They also predicted that Fiji, New Caledonia, New Zealand, Northern Cook Islands, Papua New Guinea and Tokelau, all had a near-normal risk of being impacted.[3] The outlook noted that Vanuatu and New Caledonia had a normal to reduced risk of being impacted by multiple tropical cyclones while French Polynesia's Austral Islands had a normal to reduced chance of being impacted. NIWA and partners also considered it unlikely that Pitcairn Islands, Kiribati and French Polynesia's Marquesas Islands and Tuamotu Archipelago would be impacted by a tropical cyclone.[3] The FMS's outlook predicted that the Samoan Islands, Tokelau and Tuvalu had an increased chance of being impacted by a tropical cyclone, while Fiji, the Solomon Islands, Wallis & Futuna, New Caledonia, Tonga, Niue, the southern Cook Islands and French Polynesia's Austral Islands all had a normal chance of being impacted by a tropical cyclone.[2] Their outlook also predicted that Vanuatu, the Northern Cook Islands, French Polynesia's Society Islands had a reduced chance of being affected by a tropical cyclone, while tropical cyclone activity near Kiribati and the Marquesas Islands was considered unlikely.[2] It was thought by the FMS that there was an increased risk of the Solomon Islands, Tuvalu, Wallis & Futuna, Tokelau, the Samoan Islands, Tonga and Niue being impacted by at least one severe tropical cyclone, while other areas such as the Cook Islands and parts of French Polynesia had a normal to reduced chance of being impacted by a severe tropical cyclone.[2]

Seasonal summary

The season began with the arrival of Tropical Depression 01F on November 22, near the Solomon Islands, which would later become Tropical Cyclone Rita. Rita would then peak as a Category 3 on the Australian scale.

Systems

Severe Tropical Cyclone Rita

Category 3 severe tropical cyclone (Australian scale)
Category 1 tropical cyclone (SSHWS)
 
DurationNovember 22 – November 26
Peak intensity120 km/h (75 mph) (10-min)  977 hPa (mbar)

Beginning November 21, the Fiji Meteorological Service (FMS) began highlighting the likelihood of a tropical cyclone forming between Vanuatu and Fiji.[5] Showers and thunderstorms began to aggregate in the region atop sea surface temperatures above 29 °C (84 °F) in low-wind shear conditions.[6] Imagery from microwave satellite data showed emergent rainbands wrapping towards an organising center of low pressure.[7] Late on November 22, the FMS designated the system, now east of the Solomon Islands, as Tropical Disturbance 01F.[8] The slow-moving disturbance tracked towards the south and southeast,[9] steered by a broad area of high pressure. On November 23, 01F attained tropical depression status.[10] Supported by the stout outflow of air at the upper-levels of the troposphere, shower activity became more concentrated around the center of circulation. The depression reached tropical cyclone intensity by 06:00 UTC on November 24 near the Santa Cruz Islands, earning the name Rita.[11][12][13] A well-defined and formative eye soon developed beneath the central cloud cover.[14] Continuing to intensify in favorable atmospheric conditions, Rita reached Category 2 cyclone strength by November 25 and Category 3 intensity six hours later.[15][16][17] The developing eye briefly emerged on infrared and visible satellite imagery as a ragged feature at the cyclone's center, surrounded by well-defined rainbands.[15][18]

Over the course of November 25, convective activity and organization slightly diminished due to an increase in wind shear,[19] and Rita ultimately peaked as a Category 3 tropical cyclone with 10-minute maximum sustained winds of 120 km/h (75 mph) as well as 1-minute sustained winds up to the same intensity. Additionally, Rita reached a minimum barometric pressure of 977 mbar (hPa; 28.85 inHg).[20][21] This made Rita one of the strongest first storms to form in the South Pacific since the formation of Mick in 2009, as many others were merely depressions or disurbances. It then began to track into an area unfavorable for intensification due to the presence of wind shear and cool dry air,[22] resulting in a rapid decay of the storm's convection and a decrease of the storm's maximum winds.[23][24] The FMS issued their last advisory on Rita on November 26 after the storm was downgraded to a remnant area of low pressure; at the time these remnants were slowly moving west-southwest towards northern Vanuatu.[25] In anticipation of heavy rainfall and strong winds from Rita, the National Disaster Management Office in Port Vila, Vanuatu, issued a Red Alert for Torba Province and a Yellow Alert for Penama Province and Sanma Province.[26][27] Warnings for strong winds were also issued for Shefa and Tafea provinces.[28]

Storm names

Within the Southern Pacific a tropical depression is judged to have reached tropical cyclone intensity should it reach winds of 65 km/h, (40 mph) and it is evident that gales are occurring at least halfway around the center. Tropical depressions that intensify into a tropical cyclone between the Equator and 25°S and between 160°E and 120°W are named by the FMS. However, should a tropical depression intensify to the south of 25°S between 160°E and 120°W it will be named by MetService in conjunction with the FMS. Should a tropical cyclone move out of the basin and into the Australian region it will retain its original name. The next 10 names on the naming list are listed here below.[29]

  • Rita
  • Sarai (unused)
  • Tino (unused)
  • Uesi (unused)
  • Vicky (unused)
  • Wasi (unused)
  • Yolanda (unused)
  • Zazu (unused)
  • Ana (unused)
  • Bina (unused)

Season effects

This table lists all the storms that developed in the South Pacific to the east of longitude 160°E during the 2019–20 season. It includes their intensity on the Australian tropical cyclone intensity scale, duration, name, landfalls, deaths, and damages. All data is taken from RSMC Nadi and/or TCWC Wellington, and all of the damage figures are in 2019 USD.

Name Dates active Peak classification Sustained
wind speeds
Pressure Areas affected Damage
(USD)
Deaths Refs
RitaNovember 22 – 26Category 3 severe tropical cyclone120 km/h (75 mph)977 hPa (28.85 inHg)Solomon Islands, VanuatuNoneNone
Season aggregates
1 systemNovember 22 
Season ongoing
120 km/h (75 mph)977 hPa (28.85 inHg)

See also

References

  1. Climate Services Division (October 26, 2010). Tropical Cyclone Guidance for Season 2010/11 for the Fiji and the Southwest Pacific (PDF) (Report). Fiji Meteorological Service. Archived from the original (PDF) on February 27, 2012. Retrieved October 17, 2016.
  2. 2019–20 Tropical Cyclone Season Outlook [in the] Regional Specialised Meteorological Centre Nadi – Tropical Cyclone Centre (RSMC Nadi – TCC) Area of Responsibility (AOR) (PDF) (Report). Fiji Meteorological Service. October 11, 2019. Archived (PDF) from the original on October 11, 2016. Retrieved October 11, 2019.
  3. Southwest Pacific Tropical Cyclone Outlook - October 2019 (Report). National Institute of Water and Atmospheric Research. October 11, 2019. Retrieved October 11, 2019.
  4. "South Pacific Tropical Cyclone Outlook for 2019 to 2020". Australian Bureau of Meteorology. October 11, 2019. Retrieved October 11, 2019.
  5. Tropical Cyclone - 5 Day Outlook (21 November 2019) (5 Day Outlook). Nadi, Fiji: Fiji Meteorological Service. November 21, 2019.
  6. Tropical Disturbance Summary for 22 November 0930 UTC (Tropical Disturbance Summary). Fiji Meteorological Service. November 22, 2019.
  7. Significant Tropical Weather Advisory for the Western and South Pacific Oceans (22 November 2000 UTC) (Report). United States Joint Typhoon Warning Center. November 22, 2019.
  8. Tropical Disturbance Summary for 22 November 2100 UTC (Tropical Disturbance Summary). Fiji Meteorological Service. November 22, 2019.
  9. Tropical Disturbance Advisory Number A1 for Tropical Depression 01F (Report). Fiji Meteorological Service. November 23, 2019.
  10. Tropical Disturbance Advisory Number A2 for Tropical Depression 01F (Report). Fiji Meteorological Service. November 23, 2019.
  11. Tropical Disturbance Summary for 24 November 0600 UTC (Tropical Disturbance Summary). Fiji Meteorological Service. November 24, 2019.
  12. Tropical Disturbance Advisory Number A4 for Tropical Depression 01F (Report). Fiji Meteorological Service. November 24, 2019.
  13. Tropical Cyclone 01P (One) Warning NR 001 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 24, 2019. Retrieved November 24, 2019 via Global Disaster Alert and Coordination System.
  14. Tropical Cyclone 01P (One) Warning NR 002 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 24, 2019. Retrieved November 24, 2019 via Global Disaster Alert and Coordination System.
  15. Tropical Disturbance Advisory Number A8 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 25, 2019.
  16. Hurricane Warning 013 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 25, 2019.
  17. Hurricane Warning 015 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 25, 2019.
  18. Tropical Disturbance Advisory Number A9 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 25, 2019.
  19. Tropical Cyclone 01P (Rita) Warning NR 007 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 25, 2019. Retrieved November 24, 2019 via Global Disaster Alert and Coordination System.
  20. Tropical Disturbance Advisory Number A10 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 25, 2019.
  21. Tropical Cyclone 01P (Rita) Warning NR 005 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 25, 2019. Retrieved November 24, 2019 via Global Disaster Alert and Coordination System.
  22. Tropical Cyclone 01P (Rita) Warning NR 009 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 26, 2019. Retrieved November 26, 2019 via Global Disaster Alert and Coordination System.
  23. Tropical Disturbance Advisory Number A13 for Tropical Cyclone Rita (Report). Fiji Meteorological Service. November 26, 2019.
  24. Tropical Cyclone 01P (Rita) Warning NR 011 (Tropical Cyclone Warning). United States Joint Typhoon Warning Center. November 26, 2019. Retrieved November 26, 2019 via Global Disaster Alert and Coordination System.
  25. "Former Cyclone Rita now a Tropical Low". Radio New Zealand. November 26, 2019. Retrieved November 25, 2019.
  26. "Cyclone Rita becomes category two storm". Radio New Zealand. November 25, 2019. Retrieved November 25, 2019.
  27. "Cyclone Rita to pass east of Vanuatu". Radio New Zealand. November 25, 2019. Retrieved November 25, 2019.
  28. "Vanuatu - Tropical Cyclone RITA update (GDACS, JTWC, VMGD, media) (ECHO Daily Flash of 27 November 2019)". ReliefWeb. European Commission's Directorate-General for European Civil Protection and Humanitarian Aid Operations. November 27, 2019. Retrieved November 27, 2019.
  29. RA V Tropical Cyclone Committee (October 11, 2018). Tropical Cyclone Operational Plan for the South-East Indian Ocean and the Southern Pacific Ocean 2018 (PDF) (Report). World Meteorological Organization. pp. I-4–II-9 (9–21). Archived from the original on October 12, 2018. Retrieved October 12, 2018.
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