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2012–13 South Pacific cyclone season
The 2012–13 South Pacific cyclone season was a below average tropical cyclone season, with five tropical cyclones occurring within the basin between 160°E and 120°W. The season officially ran from November 1, 2012, to April 30, 2013, however the last tropical disturbance was last noted on May 1, as it moved into the subtropics. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService. The United States Joint Typhoon Warning Center (JTWC) and other national meteorological services including Météo-France and NOAA also monitored the basin during the season. During the season there were 22 significant tropical disturbances assigned a number and a F suffix by the FMS's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi), including Severe Tropical Cyclone Sandra which moved into the basin from the Australian region on March 9. The BoM, MetService and RSMC Nadi all estimated sustained wind speeds over a period of 10-minutes and used the Australian tropical cyclone intensity scale, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHS).
Ahead of the cyclone season, RSMC Nadi, TCWC Wellington, the Australian Bureau of Meteorology (BoM), the New Zealand 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 2012. The outlook took into account the ENSO neutral conditions and near normal sea surface temperature anomalies that had been observed across the Pacific. As a result, the outlook called for a near average number of tropical cyclones for the 2012–13 season, with nine to twelve named tropical cyclones predicted to occur between 135°E and 120°W compared to an average of 10. At least two of the tropical cyclones were expected to become category 3 severe tropical cyclones, while one might intensify into a category 4 severe tropical cyclone. The outlook also noted within past analogues, category 5 severe tropical cyclones had not been prominent for ENSO neutral seasons, but the most recent analogue suggested that this type of event was possible.
In addition to contributing towards the outlook, RSMC Nadi and the BoM issued their own seasonal forecasts for the South Pacific region. The BoM issued 3 seasonal forecasts for the South Pacific region between 142.5°E and 120°W, one for the Western Southern Pacific region between 142.5°E and 165°E and one for the Eastern Southern Pacific region between 165°E and 120°W. They noted that the current neutral ENSO conditions would historically suggest the South Pacific region as a whole would experience near average tropical cyclone activity during the coming season. However, because of the warmer than average sea surface temperatures that were experienced in the central equatorial Pacific between July — September 2012, the western Southern Pacific had a 65% chance for average to below average tropical cyclone activity. For the Eastern part of the region, the BoM predicted that it had a 55% chance of above average tropical cyclones, while for the overall region, they predicted that the region would experience a near average amount of tropical cyclones with a 53% chance of having an above average number of tropical cyclones. Within their outlook RSMC Nadi predicted that between seven and ten tropical cyclones, would occur within the basin compared to an average of around 7.4 cyclones. At least four of the tropical cyclones were expected to become category 3 severe tropical cyclones, while 2–3 might intensify into a category 4 or 5 severe tropical cyclones. They also reported that the tropical cyclone genesis trough was expected to be located near the International Date Line. This was based on the ENSO Neutral conditions, and the existence of the warm pool of sea surface and sub surface temperature anomalies near the dateline.
Both the Island Climate Update and RSMC Nadi's tropical cyclone outlooks assessed the risk of a tropical cyclone affecting a certain island or territory. As the tropical cyclone genesis trough of low pressure was expected to be located near the Dateline, normal or above normal activity was expected for areas near the dateline. The Island Climate Update Outlook predicted that most of the countries to the west of the International Date Line, including Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia Tonga and Fiji were expected to experience near normal or slightly above normal activity. At least one or more severe tropical cyclones were expected to occur anywhere across the southwest Pacific during the season. RSMC Nadi's outlook predicted that New Caledonia, Southern Tonga, Tokelau, Tuvalu, Solomon Islands, Fiji and Vanuatu had an average risk of being affected by a tropical cyclone. Wallis and Futuna, Samoa, Northern Tonga, Niue, Cook Islands and French Polynesia were predicted to face an above average chance of being affected by a tropical cyclone. RSMC Nadi also predicted that there was a potential risk in the chances of severe tropical cyclones, affecting the region this year when compared to the previous season. There was a high chance of Tokelau being affected by a tropical cyclone while there was a moderate to high risk for severe tropical cyclones to affect New Caledonia, the Cook Islands, the Samoan Islands and the Solomon Islands. Wallis and Futuna, Tuvalu, Niue and Vanuatu were predicted to have a moderate risk while Fiji and Tonga were thought to have a low to moderate risk of being impacted by a severe tropical cyclone.
The first tropical disturbance of the season developed on November 6, to the southwest of Suva, Fiji which moved towards the southeast over the next day before it was last noted during the next day as it moved out of the tropics. Tropical Disturbance 02F subsequently developed on November 18 to the northeast of Port Vila, Vanuatu and over the next few days slowly moved to the west-southwest while gradually developing further. The system almost developed into a weak tropical cyclone as it moved along the Vanuatu Islands causing some locally heavy rain, minor damage and flash flooding, before it was last noted November 24 as it moved out of RSMC Nadi's area of responsibility. After 02F left the tropics, the basin remained quiet until early December when the Australian monsoon pushed eastwards along the South Pacific convergence zone, and a Madden–Julian oscillation caused an increase in tropical cyclone activity. On December 9, RSMC Nadi started to monitor the precursor systems to Tropical Depression 03F and Severe Tropical Cyclone Evan.
Tropical Disturbance 02F developed within a trough of low pressure to the north-east of the Santa Cruz Islands during November 18. Over the next few days the system moved slowly and gradually developed further in an area of low vertical wind shear and was declared a tropical depression during November 20. The system subsequently turned towards the south-southeast and impacted Vanuatu, before it moved into an area of unfavourable conditions for further development, including high vertical wind shear and lower sea surface temperatures during November 22. As a result, convection surrounding the system significantly decreased and detached from the systems low level circulation center. The system was subsequently last noted by the FMS during November 24, as it approached the subtropics as a former tropical depression. There was no damage recorded when the depression impacted Vanuatu between November 20–22. A rainfall total of 91 mm (3.6 in) was recorded at the Whitegrass Observation Station on Tanna Island during November 21, while a total of 108 mm (4.3 in) was recorded on Aneityum Island during November 22. The trough of low pressure associated with 02F, brought strong winds over Western and Southern parts of Fiji during November 22, with Ono-i-lau recording the highest sustained winds of 50 km/h (31 mph) and gusts of up to 77 km/h (48 mph).
During December 9, RSMC Nadi reported that Tropical Depression 03F had developed in an area of high vertical windshear, about 600 km (375 mi) to the northeast of Avarua on the Cook Island of Rarotonga. It was classified as a Subtropical system by the SSHWS as it reached peak intensity on December 13 but failed to be a tropical cyclone. 03F then dissipated on December 17 near a subtropical ridge.
On December 9, RSMC Nadi started to monitor a weak tropical depression, that had developed within the South Pacific convergence zone, about 700 km (435 mi) to the northeast of Suva, Fiji. Over the next two days, the depression gradually developed further in an area of low vertical windshear and favourable sea surface temperatures, as it was steered eastwards by an upper level ridge of high pressure. During December 11, the JTWC started to issue warnings and designated the system as Tropical Cyclone 04P, after 1-minute sustained winds had become equivalent to a tropical storm. RSMC Nadi then reported early the next day that the system had become a category one tropical cyclone and named it Evan, while it was located about 410 km (255 mi) to the west of Pago Pago on the American Samoan island of Tutuila.
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2012–13 South Pacific cyclone season AI simulator
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2012–13 South Pacific cyclone season
The 2012–13 South Pacific cyclone season was a below average tropical cyclone season, with five tropical cyclones occurring within the basin between 160°E and 120°W. The season officially ran from November 1, 2012, to April 30, 2013, however the last tropical disturbance was last noted on May 1, as it moved into the subtropics. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService. The United States Joint Typhoon Warning Center (JTWC) and other national meteorological services including Météo-France and NOAA also monitored the basin during the season. During the season there were 22 significant tropical disturbances assigned a number and a F suffix by the FMS's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi), including Severe Tropical Cyclone Sandra which moved into the basin from the Australian region on March 9. The BoM, MetService and RSMC Nadi all estimated sustained wind speeds over a period of 10-minutes and used the Australian tropical cyclone intensity scale, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHS).
Ahead of the cyclone season, RSMC Nadi, TCWC Wellington, the Australian Bureau of Meteorology (BoM), the New Zealand 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 2012. The outlook took into account the ENSO neutral conditions and near normal sea surface temperature anomalies that had been observed across the Pacific. As a result, the outlook called for a near average number of tropical cyclones for the 2012–13 season, with nine to twelve named tropical cyclones predicted to occur between 135°E and 120°W compared to an average of 10. At least two of the tropical cyclones were expected to become category 3 severe tropical cyclones, while one might intensify into a category 4 severe tropical cyclone. The outlook also noted within past analogues, category 5 severe tropical cyclones had not been prominent for ENSO neutral seasons, but the most recent analogue suggested that this type of event was possible.
In addition to contributing towards the outlook, RSMC Nadi and the BoM issued their own seasonal forecasts for the South Pacific region. The BoM issued 3 seasonal forecasts for the South Pacific region between 142.5°E and 120°W, one for the Western Southern Pacific region between 142.5°E and 165°E and one for the Eastern Southern Pacific region between 165°E and 120°W. They noted that the current neutral ENSO conditions would historically suggest the South Pacific region as a whole would experience near average tropical cyclone activity during the coming season. However, because of the warmer than average sea surface temperatures that were experienced in the central equatorial Pacific between July — September 2012, the western Southern Pacific had a 65% chance for average to below average tropical cyclone activity. For the Eastern part of the region, the BoM predicted that it had a 55% chance of above average tropical cyclones, while for the overall region, they predicted that the region would experience a near average amount of tropical cyclones with a 53% chance of having an above average number of tropical cyclones. Within their outlook RSMC Nadi predicted that between seven and ten tropical cyclones, would occur within the basin compared to an average of around 7.4 cyclones. At least four of the tropical cyclones were expected to become category 3 severe tropical cyclones, while 2–3 might intensify into a category 4 or 5 severe tropical cyclones. They also reported that the tropical cyclone genesis trough was expected to be located near the International Date Line. This was based on the ENSO Neutral conditions, and the existence of the warm pool of sea surface and sub surface temperature anomalies near the dateline.
Both the Island Climate Update and RSMC Nadi's tropical cyclone outlooks assessed the risk of a tropical cyclone affecting a certain island or territory. As the tropical cyclone genesis trough of low pressure was expected to be located near the Dateline, normal or above normal activity was expected for areas near the dateline. The Island Climate Update Outlook predicted that most of the countries to the west of the International Date Line, including Papua New Guinea, the Solomon Islands, Vanuatu, New Caledonia Tonga and Fiji were expected to experience near normal or slightly above normal activity. At least one or more severe tropical cyclones were expected to occur anywhere across the southwest Pacific during the season. RSMC Nadi's outlook predicted that New Caledonia, Southern Tonga, Tokelau, Tuvalu, Solomon Islands, Fiji and Vanuatu had an average risk of being affected by a tropical cyclone. Wallis and Futuna, Samoa, Northern Tonga, Niue, Cook Islands and French Polynesia were predicted to face an above average chance of being affected by a tropical cyclone. RSMC Nadi also predicted that there was a potential risk in the chances of severe tropical cyclones, affecting the region this year when compared to the previous season. There was a high chance of Tokelau being affected by a tropical cyclone while there was a moderate to high risk for severe tropical cyclones to affect New Caledonia, the Cook Islands, the Samoan Islands and the Solomon Islands. Wallis and Futuna, Tuvalu, Niue and Vanuatu were predicted to have a moderate risk while Fiji and Tonga were thought to have a low to moderate risk of being impacted by a severe tropical cyclone.
The first tropical disturbance of the season developed on November 6, to the southwest of Suva, Fiji which moved towards the southeast over the next day before it was last noted during the next day as it moved out of the tropics. Tropical Disturbance 02F subsequently developed on November 18 to the northeast of Port Vila, Vanuatu and over the next few days slowly moved to the west-southwest while gradually developing further. The system almost developed into a weak tropical cyclone as it moved along the Vanuatu Islands causing some locally heavy rain, minor damage and flash flooding, before it was last noted November 24 as it moved out of RSMC Nadi's area of responsibility. After 02F left the tropics, the basin remained quiet until early December when the Australian monsoon pushed eastwards along the South Pacific convergence zone, and a Madden–Julian oscillation caused an increase in tropical cyclone activity. On December 9, RSMC Nadi started to monitor the precursor systems to Tropical Depression 03F and Severe Tropical Cyclone Evan.
Tropical Disturbance 02F developed within a trough of low pressure to the north-east of the Santa Cruz Islands during November 18. Over the next few days the system moved slowly and gradually developed further in an area of low vertical wind shear and was declared a tropical depression during November 20. The system subsequently turned towards the south-southeast and impacted Vanuatu, before it moved into an area of unfavourable conditions for further development, including high vertical wind shear and lower sea surface temperatures during November 22. As a result, convection surrounding the system significantly decreased and detached from the systems low level circulation center. The system was subsequently last noted by the FMS during November 24, as it approached the subtropics as a former tropical depression. There was no damage recorded when the depression impacted Vanuatu between November 20–22. A rainfall total of 91 mm (3.6 in) was recorded at the Whitegrass Observation Station on Tanna Island during November 21, while a total of 108 mm (4.3 in) was recorded on Aneityum Island during November 22. The trough of low pressure associated with 02F, brought strong winds over Western and Southern parts of Fiji during November 22, with Ono-i-lau recording the highest sustained winds of 50 km/h (31 mph) and gusts of up to 77 km/h (48 mph).
During December 9, RSMC Nadi reported that Tropical Depression 03F had developed in an area of high vertical windshear, about 600 km (375 mi) to the northeast of Avarua on the Cook Island of Rarotonga. It was classified as a Subtropical system by the SSHWS as it reached peak intensity on December 13 but failed to be a tropical cyclone. 03F then dissipated on December 17 near a subtropical ridge.
On December 9, RSMC Nadi started to monitor a weak tropical depression, that had developed within the South Pacific convergence zone, about 700 km (435 mi) to the northeast of Suva, Fiji. Over the next two days, the depression gradually developed further in an area of low vertical windshear and favourable sea surface temperatures, as it was steered eastwards by an upper level ridge of high pressure. During December 11, the JTWC started to issue warnings and designated the system as Tropical Cyclone 04P, after 1-minute sustained winds had become equivalent to a tropical storm. RSMC Nadi then reported early the next day that the system had become a category one tropical cyclone and named it Evan, while it was located about 410 km (255 mi) to the west of Pago Pago on the American Samoan island of Tutuila.