2017–18 South Pacific cyclone season

The 2017–18 South Pacific cyclone season was a slightly below-average season that produced 6 tropical cyclones, 3 of which became severe tropical cyclones. The season officially began on November 1, 2017 and ended on April 30, 2018; however, a tropical cyclone could form at any time between July 1, 2017 and June 30, 2018 and would count towards the season total. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service, MetService and the Australian Bureau of Meteorology, while the United States Joint Typhoon Warning Center (JTWC) also monitored the basin and issued warnings for American interests. The FMS attaches a number and an F suffix to significant tropical disturbances that form in or move into the basin, while the JTWC designates significant tropical cyclones with a number and a P suffix. The BoM, FMS and MetService all use the Australian Tropical Cyclone Intensity Scale and estimate wind speeds over a period of ten minutes, while the JTWC estimates sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

2017–18 South Pacific cyclone season
Season summary map
Seasonal boundaries
First system formedDecember 16, 2017
Last system dissipatedApril 20, 2018
Strongest storm
NameGita
 • Maximum winds205 km/h (125 mph)
(10-minute sustained)
 • Lowest pressure927 hPa (mbar)
Seasonal statistics
Total disturbances14
Total depressions10
Tropical cyclones6
Severe tropical cyclones3
Total fatalities11 total
Total damage$377 million (2017 USD)
Related articles

Seasonal forecasts
Source/Record Tropical
Cyclone		 Severe
Tropical Cyclone		 Ref
Record high:1997–98: 161982–83: 10[1]
Record low:2011–12:  32008–09:  0[1][2]
Average (1969-70 - 2016-17):7.1 —[2]
NIWA October8-103-4[3]
Fiji Meteorological Service4-61-3[2]
Region Chance of
above average		 Average
number		 Actual
activity
Western South Pacific 48% 7 5
Eastern South Pacific 55% 4 0
Source:BOM's South Pacific Tropical Cyclone Season Outlook.[4]

Ahead of the cyclone season, 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 2016.[3] The outlook took into account the ENSO neutral conditions that had been observed across the Pacific and analogue seasons that had ENSO neutral and weak La Nina conditions occurring during the season.[3] The outlook called for a near average number of tropical cyclones for the 2017–18 season, with eight to ten named tropical cyclones, to occur between 135°E and 120°W compared to an average of about 10.[3] At least three of the tropical cyclones were expected to become Category 3 severe tropical cyclones, while two could become Category 4 severe tropical cyclones; they also noted that a Category 5 severe tropical cyclone was not likely to 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 48% chance of seeing activity above its average of 7 tropical cyclones. The BoM also predicted that the Eastern Region between 165°E and 120°W, had a 55% chance of seeing activity above its average of 4 tropical cyclones.[4] Within their outlook the FMS predicted that between four and six tropical cyclones, would occur within the basin compared to an average of around 7.1 cyclones.[2] At least one of the tropical cyclones was expected to intensify into a Category 3 or higher severe tropical cyclone.[2] They also predicted that the main area for tropical cyclogenesis would be within the Coral Sea, to the west of the International Dateline.[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 New Caledonia, Tonga, New Zealand and Papua New Guinea had an above average chance of being impacted by a tropical cyclone or their remnants.[3] They also predicted that the Solomon Islands, Fiji and Vanuatu had a near normal to normal risk of being impacted by one or more tropical cyclones.[3] The Southern Cook Islands, American Samoa, Samoa, Niue, Tokelau, Tuvalu, as well as Wallis and Futuna were thought to have a below average chance of being impacted. It was also considered unlikely that the Northern Cook Islands, French Polynesia, Kiribati and the Pitcairn Islands would be affected by a tropical cyclone.[3] The FMS's outlook predicted that Vanuatu, New Caledonia, Fiji as well as Wallis and Futuna had a normal chance of being impacted by a tropical cyclone.[2] The outlook also predicted that the Solomon Islands, Tokelau, Samoa, Tonga, Niue, Cook Islands and French Polynesia had a reduced chance of being affected by a tropical cyclone.[2] It was thought that there was a normal risk of Vanuatu, New Caledonia, Fiji and Samoa being impacted by at least one severe tropical cyclone, while other areas such as the Solomon Islands, Tokelau, Samoa, Tonga, Niue and French Polynesia, had a reduced chance of being impacted by a severe tropical cyclone.[2]

Seasonal summary
Cyclone HolaCyclone Gita

Systems

Tropical Depression 04F
Tropical depression (Australian scale)
 
DurationDecember 20 – December 26
Peak intensityWinds not specified  998 hPa (mbar)

Tropical Disturbance 05F
Tropical disturbance (Australian scale)
 
DurationJanuary 26 – January 27
Peak intensityWinds not specified  996 hPa (mbar)

Tropical Cyclone Fehi
Category 1 tropical cyclone (Australian scale)
Tropical storm (SSHWS)
 
DurationJanuary 28 (Entered basin) – January 30
Peak intensity85 km/h (50 mph) (10-min)  986 hPa (mbar)

As a tropical cyclone, Fehi caused extensive damage in western New Zealand. Strong winds and heavy rain damaged hundreds of structures, with more than 100 later condemned. Waist-deep water flooded homes in Charleston and Westport. Pounding surf eroded beaches, exposing an old garbage dump at Cobden Beach which left thousands of garbage bags strewn about. Insurance loss were amounted at NZ$38.5 million (US$28.5 million).[5]

Severe Tropical Cyclone Gita
Category 5 severe tropical cyclone (Australian scale)
Category 4 tropical cyclone (SSHWS)
 
DurationFebruary 3 – February 19
Peak intensity205 km/h (125 mph) (10-min)  927 hPa (mbar)
Main article: Cyclone Gita

Tropical Depression 08F
Tropical depression (Australian scale)
 
DurationFebruary 3 – February 11
Peak intensityWinds not specified  994 hPa (mbar)

Severe Tropical Cyclone Hola
Category 4 severe tropical cyclone (Australian scale)
Category 3 tropical cyclone (SSHWS)
 
DurationMarch 3 – March 11
Peak intensity165 km/h (105 mph) (10-min)  952 hPa (mbar)
Main article: Cyclone Hola

During March 3, 2018 the Fiji Meteorological Service (FMS) reported that Tropical Disturbance 09F had developed within a trough of low pressure about 230 km (145 mi) to the northeast of Nadi, Fiji.[6][7] At this time the disturbance had a broad low-level circulation and was located within a very favourable environment for further development, with low vertical wind shear and warm sea surface temperatures.[8] Over the next couple of days, the disturbance gradually developed further as it gradually moved westwards towards Vanuatu, under the influence of a subtropical ridge of high pressure.[8][9] It was subsequently classified as a tropical depression by the FMS during March 5, before the United States Joint Typhoon Warning Center (JTWC) subsequently issued a tropical cyclone formation alert on the system later that day.[10][11]

During March 6, the JTWC initiated advisories on the system and designated it as Tropical Cyclone 12P, after its broad low-level circulation center had slowly consolidated and the overall organisation of the cyclone had improved.[12] The FMS subsequently reported that the system had developed into a Category 1 tropical cyclone on the Australian tropical cyclone intensity scale and named it Hola, while it was located about 80 km (50 mi) to the east of Pentecost Island in Vanuatu.[13] After it was named, Hola started developing a weak low level eye feature, before it was classified as a category 2 tropical cyclone as it passed in between the islands of Pentecost and Ambrym.[14][15] The system subsequently passed over the island of Malekula and moved into the Coral Sea during March 7, where it rapidly consolidated and developed a 10 km (5 mi) pinhole eye.[16][17] The FMS subsequently reported that Hola had become a Category 4 Severe Tropical Cyclone and predicted that Hola would peak as a Category 5 Severe Tropical Cyclone.[18]


Tropical Depression 10F (Linda)
Tropical depression (Australian scale)
Tropical storm (SSHWS)
 
DurationMarch 11 – March 13 (Exited basin)
Peak intensity55 km/h (35 mph) (10-min)  998 hPa (mbar)

On March 11, the FMS reported that Tropical Disturbance 10F, had developed about 85 km (55 mi) to the southwest of Rennell and Bellona Province of the Solomon Islands.[19] The system was poorly organised with deep atmospheric convection, displaced to the east of the system's consolidating low-level circulation center. The disturbance was subsequently classified as Tropical Low 21U by the BoM during March 12, as it moved southwards within an area of low vertical wind shear and warm sea surface temperatures.[20][21] The JTWC initiated advisories on the system later that day and classified the storm as Tropical Cyclone 13P, after the system had rapidly consolidated, with bands of atmospheric convection wrapping into the low-level circulation center.

Tropical Cyclone Iris
Category 1 tropical cyclone (Australian scale)
 
DurationMarch 20 – March 24 (Exited basin)
Peak intensity75 km/h (45 mph) (10-min)  993 hPa (mbar)

During March 20, the FMS reported that Tropical Disturbance 11F had developed within an area of low to moderate vertical wind shear, over the eastern Solomon Islands around 200 km (125 mi) to the east of Honiara.[22] At this time the system was poorly organised with deep atmospheric convection, located to the east of the low-level circulation centre.[22] Over the next few days, the system remained weak as it moved erratically around the Solomon Islands and was classified as a tropical depression during March 22.[23][24]

On March 24, Tropical Depression 11F strengthened into Tropical Cyclone Iris. Later on the same day, Iris exited the basin and entered the Australian region basin.

Tropical Cyclone Josie
Category 1 tropical cyclone (Australian scale)
Tropical storm (SSHWS)
 
DurationMarch 29 – April 2
Peak intensity75 km/h (45 mph) (10-min)  993 hPa (mbar)

Despite not making landfall, Tropical Cyclone Josie caused heavy rainfall and sustained gale-force winds in southern Fiji.[25] Severe flooding occurred in the city of Nadi,[26] and at least five people were washed away by floodwaters, of which four are confirmed dead and one is still missing.[25]

Severe Tropical Cyclone Keni
Category 3 severe tropical cyclone (Australian scale)
Category 2 tropical cyclone (SSHWS)
 
DurationApril 5 – April 11
Peak intensity155 km/h (100 mph) (10-min)  960 hPa (mbar)

Tropical Cyclone Keni impacted Fiji and caused the cast and crew of the 37th season of the American reality competition series, Survivor, to be temporarily evacuated to the production's base camp.[27][28]

Tropical Depression 14F
Tropical depression (Australian scale)
 
DurationApril 17 – April 20
Peak intensityWinds not specified  1000 hPa (mbar)

Other systems
Subtropical Cyclone "Lexi" near Chile on May 7

During December 16, Tropical Disturbance 02F developed within a trough of low pressure, about 25 km (15 mi) to the northeast of the island of Futuna.[29][30] During the following day, Tropical Disturbance 03F developed along the same trough of low pressure about 45 km (30 mi) to the southeast of the island of Wallis.[30][31] Over the next couple of days, the disturbances moved southeastwards into areas of high vertical wind shear, before they were last noted during December 18 and 19 as they dissipated to the southeast of Samoa.[32][33]

On January 28, the JTWC issued a tropical cyclone formation alert on a tropical disturbance, which was located near the French Polynesian island of Rapa Iti.[34] The system had a well defined low-level circulation, and was located within an area of warm sea surface temperatures and marginal vertical wind shear.[34] The system subsequently peaked with 1-minute sustained wind speeds of 65 km/h (40 mph), which made it equivalent to a tropical storm.[35] The alert was subsequently cancelled during the next day, after the system's low level circulation center became ragged, while atmospheric convection was displaced to the east of the circulation center.[36]

On May 4, 2018, a system identified as a subtropical cyclone formed east of 120°W, just a few hundred miles off the coast of Chile, with researchers unofficially naming the storm Lexi.[37] The cyclone formed in an area without a Regional Specialized Meteorological Center, so it was not officially classified.[38] On May 9, the satellite services division of the NOAA classified the system as a weak subtropical storm, despite occurring in cooler (below 20°C) sea surface temperatures.[39]

Season effects

This table lists all the storms that developed in the South Pacific to the east of longitude 160°E during the 2017–18 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 2017 USD.

Name Dates active Peak classification Sustained
wind speeds		 Pressure Areas affected Damage
(USD)		 Deaths Refs
02FDecember 16 – 18Tropical disturbanceNot Specified1003 hPa (29.62 inHg)NoneNoneNone
03FDecember 17 – 19Tropical disturbanceNot Specified1000 hPa (29.53 inHg)NoneNoneNone
04FDecember 20 – 26Tropical depressionNot Specified998 hPa (29.47 inHg)FijiNoneNone
05FJanuary 26 – 27Tropical disturbanceNot Specified996 hPa (29.41 inHg)New CaledoniaNoneNone
FehiJanuary 28 – 30Category 1 tropical cyclone85 km/h (50 mph)986 hPa (29.12 inHg)New Caledonia, New Zealand$67 millionNone[40]
GitaFebruary 3 – 19Category 5 severe tropical cyclone205 km/h (125 mph)927 hPa (27.37 inHg)Fiji, Wallis and Futuna, Samoan Islands, Niue,
Tonga, New Caledonia, New Zealand		$250 million2[40]
08FFebruary 3 – 11Tropical depressionNot Specified994 hPa (29.35 inHg)FijiNoneNone
HolaMarch 3 – 11Category 4 severe tropical cyclone165 km/h (105 mph)952 hPa (28.11 inHg)Fiji, Vanuatu, New Caledonia, New ZealandUnknown3[41][42]
10FMarch 11 – 12Tropical depressionNot Specified998 hPa (29.47 inHg)NoneNoneNone
IrisMarch 20 – 24Category 1 tropical cyclone75 km/h (45 mph)993 hPa (29.32 inHg)Solomon IslandsNoneNone
JosieMarch 29 – April 2Category 1 tropical cyclone75 km/h (45 mph)993 hPa (29.32 inHg)Vanuatu, Fiji, Tonga$10 million6[40]
KeniApril 5 – 11Category 3 severe tropical cyclone140 km/h (85 mph)970 hPa (28.64 inHg)Vanuatu, Fiji, Tonga$50 millionNone[40]
14FApril 17 – 20Tropical depressionNot Specified1000 hPa (29.53 inHg)RotumaUnknownUnknown
Season aggregates
13 systemsNovember 28 – April 20205 km/h (125 mph)927 hPa (27.37 inHg)$377 million11
gollark: .
gollark: It would indeed be a problem for 100Gs or something like that
gollark: I'd personally like to be able to see all of a lineage by scrolling.
gollark: So the way to defeat SunFish is to push them to the cave, where they will be taken apart by cavegoers and cause a rare drought for years.
gollark: *xenowyrm xenowyrms*

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. "2017–18 Tropical Cyclone Season Outlook in the Regional Specialised Meteorological Centre Nadi – Tropical Cyclone Centre (RSMC Nadi – TCC) Area of Responsibility (AOR)" (PDF). Fiji Meteorological Service. October 11, 2017. Archived (PDF) from the original on 2017-10-11. Retrieved October 11, 2017.
  3. "Southwest Pacific Tropical Cyclone Outlook - October 2017". National Institute of Water and Atmospheric Research. October 10, 2017. Archived from the original on 2017-10-11. Retrieved October 10, 2017.
  4. National Climate Centre (October 9, 2017). "South Pacific Tropical Cyclone Outlook for 2017 to 2018". Australian Bureau of Meteorology. Archived from the original on 2016-04-13. Retrieved October 11, 2017.
  5. "CYCLONE FEHI SET TO COST MORE THAN $39M". ICNZ. March 21, 2018. Retrieved March 21, 2018.
  6. "Heavy Rain and Flood Alerts in force" (PDF) (Press release). Fiji Meteorological Service. March 3, 2018. Archived (PDF) from the original on March 8, 2018. Retrieved March 7, 2018.
  7. "Tropical Disturbance Summary March 3, 2018 09z". Fiji Meteorological Service. March 3, 2018. Archived from the original on March 3, 2018. Retrieved March 7, 2018.
  8. "Significant Tropical Weather Advisory for the Western and South Pacific Oceans March 3, 2018 10z". United States Joint Typhoon Warning Center. March 3, 2018. Archived from the original on March 3, 2018. Retrieved March 8, 2018.
  9. "TD09F moving further away from the group" (PDF) (Press release). Fiji Meteorological Service. March 6, 2018. Archived (PDF) from the original on March 8, 2018. Retrieved March 8, 2018.
  10. "Tropical Disturbance Summary March 5, 2018 06z". Fiji Meteorological Service. March 5, 2018. Archived from the original on March 5, 2018. Retrieved March 7, 2018.
  11. "Tropical Cyclone Formation Alert March 5 2018 14z". United States Joint Typhoon Warning Center. March 5, 2018. Archived from the original on March 5, 2018. Retrieved March 8, 2018.
  12. "Tropical Cyclone 12P (Hola) Warning March 6, 2018 15z". United States Joint Typhoon Warning Center. March 6, 2018. Archived from the original on March 6, 2018. Retrieved March 8, 2018.
  13. "Tropical Disturbance Advisory March 6, 2018 12z". Fiji Meteorological Service. March 6, 2018. Archived from the original on March 6, 2018. Retrieved March 8, 2018.
  14. "Tropical Cyclone 12P (Hola) Warning March 6, 2018 21z". United States Joint Typhoon Warning Center. March 6, 2018. Archived from the original on March 7, 2018. Retrieved March 8, 2018.
  15. "Tropical Disturbance Advisory March 6, 2018 18z". Fiji Meteorological Service. March 6, 2018. Archived from the original on March 7, 2018. Retrieved March 8, 2018.
  16. "Tropical Disturbance Advisory March 7, 2018 00z". Fiji Meteorological Service. March 7, 2018. Archived from the original on March 7, 2018. Retrieved March 8, 2018.
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  19. "Archived copy". Archived from the original on 2018-03-18. Retrieved 2018-03-18.CS1 maint: archived copy as title (link)
  20. "Archived copy". Archived from the original on 2018-03-12. Retrieved 2018-03-12.CS1 maint: archived copy as title (link)
  21. "Archived copy". Archived from the original on 2018-03-12. Retrieved 2018-03-12.CS1 maint: archived copy as title (link)
  22. Tropical Disturbance Summuary March 20, 2018 21z (Report). Fiji Meteorological Service. March 20, 2018. Archived from the original on March 21, 2018. Retrieved January 6, 2019.
  23. http://www.bom.gov.au/announcements/sevwx/qld/qldtc20180324.shtml
  24. "Archived copy". Archived from the original on 2018-03-22. Retrieved 2018-03-22.CS1 maint: archived copy as title (link)
  25. "Tropical Cyclone Josie kills 4 in Fiji". Newshub. Retrieved 2018-04-01.
  26. "Tropical Cyclone Josie puts Fiji tourist town under water". www.9news.com.au. Retrieved 2018-04-01.
  27. Ross, Dalton (25 October 2018). "'Survivor' host Jeff Probst reveals where cast went during cyclone". Entertainment Weekly. Retrieved 25 October 2018.
  28. Wigler, Josh (26 September 2018). "'Survivor David vs. Goliath': The Inside Story of That Shocking Season Premiere". The Hollywood Reporter. Retrieved 25 October 2018.
  29. Tropical Disturbance Summuary December 16, 2017 23z (Report). Fiji Meteorological Service. December 16, 2017. Archived from the original on December 17, 2017. Retrieved October 16, 2018.
  30. Climate Services Division (January 8, 2018). Fiji Islands Climate Summary December 2017 Volume 38 Issue 12 (PDF) (Report). 38. Fiji Meteorological Service. Archived from the original (PDF) on October 17, 2018. Retrieved October 16, 2018.
  31. Tropical Disturbance Summuary December 17, 2017 23z (Report). Fiji Meteorological Service. December 17, 2017. Archived from the original on December 18, 2017. Retrieved October 16, 2018.
  32. Tropical Disturbance Summuary December 18, 2017 23z (Report). Fiji Meteorological Service. December 18, 2017. Archived from the original on December 17, 2017. Retrieved October 16, 2018.
  33. http://www.wmo.int/pages/prog/www/Documents/RAV_TCC-17_DOC4.2.6_SAMOA.pdf
  34. "Tropical Cyclone Formation Alert January 28, 2018 18z". United States Joint Typhoon Warning Center. January 28, 2018. Archived from the original on 2018-01-28. Retrieved January 29, 2018.
  35. https://web.archive.org/web/20180213011619/http://ftp.emc.ncep.noaa.gov/wd20vxt/hwrf-init/decks/bsh942018.dat
  36. "Tropical Cyclone Formation Alert Cancellation January 29, 2018 18z". United States Joint Typhoon Warning Center. January 29, 2018. Archived from the original on 2018-01-28. Retrieved January 29, 2018.
  37. Steve Young (5 July 2018). "Monthly Global Tropical Cyclone Tracks - May 2018". Australia Severe Weather. Retrieved 3 September 2018.
  38. "Subtropical Cyclone". May 7, 2018.
  39. "Rare Subtropical Storm off the Coast of Chile". May 9, 2018.
  40. Weather, Climate & Catastrophe Insight: 2018 Annual Report (pdf) (Report). Aon Benfield. 22 January 2019. Retrieved 24 January 2018.
  41. "Cyclone Hola Kills 1, Injures 2 In Vanuatu". Urdupoint. 9 March 2018.
  42. "Two More Tc Hola Deaths Confirmed". 14 March 2018.
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