2005–06 South Pacific cyclone season

Seasonal forecasts

During October 2005, both RSMC Nadi and New Zealand's National Institute of Water and Atmospheric Research issued seasonal forecasts which contained information on what was expected to occur during the 2005-06 tropical cyclone season. Both agencies expected that the season would see a near average amount of tropical cyclone activity due there being no El Niño or La Nina. As a result of these conditions RSMC Nadi predicted that between 7-9 tropical cyclones would develop while NIWA did not predict how many tropical cyclone there would be during the season. RSMC Nadi also reported that Fiji had a higher chance of being hit by a tropical cyclone this season than during recent previous seasons. NIWA also predicted that there was an average risk of a tropical cyclone coming within 550 km (340 mi), of: Fiji, Tonga, Niue, Vanuatu, New Caledonia, Wallis and Futuna, the Southern Cook Islands, Samoa, and New Zealand.

Tropical Depression 01F

Formed on November 30 and dissipated on December 2, 2005.

Tropical Depression 02F

Formed on December 3 and dissipated on December 6, 2005.

Tropical Depression 03F

Formed on December 8 and dissipated on December 18, 2005.

Tropical Cyclone Tam

Tam originated as Tropical Depression 04F near 15°S 179.5°E on January 6. The system then lingered around for a few days, appearing to significantly weaken, only to strengthen later. As Tam moved southeastward on January 12, a gale warning was issued for Tonga and later for Niue as well as American Samoa. Tam accelerated towards south-southeast and became extratropical on January 14. Tam was the first tropical cyclone to occur within the area of responsibility of TCWC Wellington this year.

Tropical Depression 05F

Formed on January 10 and dissipated on January 13, 2006.

Tropical Cyclone Urmil

The second named storm of the season formed out of a weak tropical disturbance on January 13. Later that day, the RSMC in Nadi began issuing advisories on the system and classified it as Tropical Depression 06F while located about 370 km (230 mi) west of Pago Pago, American Samoa. With favorable environmental conditions in the wake of Tropical Cyclone Tam, the depression rapidly organized, strengthening into a Category 1 cyclone six hours after the first advisory was issued and was given the name Urmil. Several hours later, the JTWC also began issuing advisories on Urmil, designating it as Tropical Cyclone 07P. On January 14, Urmil underwent a brief period explosive deepening, attaining its peak intensity of 110 km/h (70 mph 10-min). Not long after reaching its peak, increased wind shear, cooler waters, and faster forward motion caused the storm to weaken. By January 15, Urmil transitioned into an extratropical cyclone. Later that day, the remnants of the storm were absorbed into the mid-latitude westerlies.

Tropical Cyclone Urmil had little impact on land, with gale-force winds being felt only in Tonga. Heavy rains exaggerated flooding produced by Cyclone Tam earlier in January and caused minor crop damages.

Tropical Depression 07F

The seventh depression of the season developed on January 15 as Urmil was dissipating. A weak system, 07F formed out of a slow moving tropical disturbance about 790 km (490 mi) north of Fiji. The system peaked in intensity with winds of 30 km/h (15 mph) later that day. On January 16, the low dissipated about 325 km (200 mi) west-northwest of Fiji.

Severe Tropical Cyclone Jim

Cyclone Jim originated in the Australian region, and moved into Fiji's area of responsibility on January 30. Jim gradually turned south-southeastward and became extratropical on February 1.

The extratropical remnants of Jim (08F) lingered around and then moved northwest. On February 3, 08F was again mentioned in a bulletin issued by Fiji. However, on the following day, the number 08F was dropped in Fiji bulletin while Brisbane called it a tropical low instead of Ex-Jim. The low was quasi-stationary and gradually weaken afterwards. It is questionable whether this system is a continuation of Jim.

Despite being well to the west of that country, Cyclone Jim was blamed for extensive flooding in Fiji, with the western coast of the island of Viti Levu – including the city of Lautoka – inundated by floodwaters on January 29. No fatalities were reported in any of the areas affected by the cyclone.

Tropical Depression 09F

Early on January 30, RSMC Nadi reported that Tropical Depression 09F had formed about 230 km, (145 mi), to the northeast of New Caledonia. As the convection was detached from the low level circulation center, and was being steered into an environment of increasing vertical windshear, RSMC Nadi immediately issued their final advisory on the system.

Tropical Depression 10F

The tenth depression of the season formed on February 2 about 150 km (95 mi) southwest of Niue. High wind shear prevented significant strengthening, with winds peaking at 55 km/h (35 mph) and a minimum pressure of 998 hPa (mbar). Tracking in an erratic, southerly direction, the depression slowly weakened as convection was displaced by wind shear. Tropical Depression 10F was last monitored on February 4 about 740 km (460 mi) southeast of Tongatapu.

Tropical Depression 11F

Formed on February 8 and dissipated on February 10, 2006.

Severe Tropical Cyclone Vaianu

Tropical Depression 12F formed near 14.5°S 176.1°W on February 10 and a tropical cyclone alert was raised in Tonga. This is the third tropical system to threaten Tonga this season. At that time, another Tropical Depression (11F) was to its south causing unstable movements of the two depressions. On the next day, 12F became the dominant system and moved south. Strengthening into Tropical Cyclone Vaianu, it turned southwest and passed between Fiji and Tonga. On February 13, Vaianu resumed a southward track and reached hurricane intensity. Vaianu then struck the Tonga islands as a Category 1 cyclone on the Saffir-Simpson scale, knocking down power lines and flattening crops, such as banana and mango trees. In Nukuʻalofa, low lying areas were shut down because of flooding. On February 13, Vaianu reached its peak intensity of 85 mp/h, but these peak winds were well away from the Tonga and Fiji islands, but Tonga still felt Vaianu's winds. Then, the cyclone accelerated towards the southeast, entered TCWC Wellington's area of responsibility and became extratropical on February 16.

Tropical Depression 13F

Formed on February 19 and dissipated on February 26, 2006.

Severe Tropical Cyclone Wati

Tropical Depression 16F formed on March 17 and strengthened into Tropical Cyclone Wati on March 19 north of New Caledonia. It moved westwards and slowly strengthened into a Category 3 cyclone on the Australian scale before coming to a near standstill over the Coral Sea. After remaining stationary for most of March 22, Wati took a southeasterly course on March 23, gaining speed and continuing that course on March 24. A cyclone watch was issued for Lord Howe Island and a cyclone warning was issued for Norfolk Island. Wati passed between the two islands and became extratropical on March 25.

The remains of Wati brought heavy rain and strong winds to the North Island of New Zealand on March 26, with gusts of 140 km/h reported at Cape Reinga.

Other systems

Tropical Depression 13F was first noted by the FMS during February 19, while it was located about 675 km (420 mi) to the southeast of Guadalcanal in the Solomon Islands.

During March 13, the FMS reported that Tropical Depression 14F had developed about 225 km (140 mi) to the southeast of Port Vila, Vanuatu. The system was slowly moving within an area of high vertical wind shear with atmospheric convection, displaced about 220 km (135 mi) to the east of the low level circulation centre. Over the next couple of days the system moved southwards and never became well organised, before it was last noted by the FMS during March 16. The precursor tropical low to Severe Tropical Cyclone Larry moved into the basin, from the Australian region and was assigned the designator 16F by the FMS during March 16. However, during that day the system recurved and moved back into the Australian region during the next day, where it later made landfall near Innisfail, Queensland and caused widespread damage to Queensland. During April 20, the FMS reported that Tropical Depression 17F had developed to the east of the International Dateline, about 500 km (310 mi) to the southeast of Suva, Fiji. Over the next day the system moved south-eastwards and remained weak and exposed, with deep convection displaced to the south and east of the low level circulation centre. The system was subsequently last noted by the FMS during April 21, as it left the tropics. During the final days of April, several depressions to the east of the International Dateline were noted by the FMS, however, none of these were referred to as tropical depressions.