[2] Both outlooks also predicted that the majority of systems would occur to the west of the International Dateline, which as a result, meant that New Caledonia had an elevated chance of being impacted by a tropical cyclone.

[3] On December 8, a disturbance formed near Fiji, starting the 2020–21 South Pacific Ocean cyclone season, it gradually intensified into a depression and attained a tropical storm status according to JTWC.

Yasa became the third most intense tropical cyclone of 2020, behind only Goni and Haishen with a minimum barometric pressure of 917 mb (27.08 inHg) and a maximum wind speed of 230 km/h (145 mph).

[5] Over the next couple of days, the system gradually moved westwards before the FMS classified it as a tropical depression during December 11, while it was located about 280 km (175 mi) to the west of the Fijian Dependency of Rotuma.

[7] The depression continued to consolidate, with deep convection wrapping into the centre of the system from the northern semicircle, and by 12:00 UTC, one-minute sustained winds had increased to 75 km/h (45 mph).

[8] By 00:00 UTC on December 12, both the JTWC and the FMS reported that the shear had displaced the system's deep convection to the northeast, leaving the center of circulation fully exposed.

[6] Environmental conditions were very favourable for tropical cyclogenesis, with radial outflow in the upper troposphere, low vertical wind shear, and sea surface temperatures near 30 °C (86 °F).

[14] At 00:00 UTC on December 12, the Fiji Meteorological Service (FMS) upgraded the system to Tropical Depression 02F and began issuing forecast track maps.

[18] About a day later, on December 13, the FMS determined that the depression had further strengthened to Category 1 status, as convection continued wrapping into the center, with the storm acquiring the name Yasa.

Just about 12 hours later on December 14, Yasa rapidly intensified to Category 4 status on the Australian scale as a defined eye began to clear on infrared satellite imagery.

[21] The storm continued rapidly intensifying and strengthened to a Category 5 tropical cyclone on the Australian scale, the highest rating possible, while completing its loop, with a central pressure of 929 mbar and wind speeds of 110 knots (125  mph).

At 18:00 UTC, Yasa's maximum 10-minute sustained winds increased to 230 km/h (140 mph), with a minimum atmospheric pressure of 917 hPa (27.08 inHg),[24] making the system one of the most intense tropical cyclones ever recorded in the Southern Hemisphere.

[citation needed] During December 11, the FMS reported that Tropical Disturbance 03F had developed about 480 km (300 mi) to the northeast of the island nation of Niue.

[6] Deep convection near the system was initially only fragmented; however, environmental conditions were assessed as being conducive for development, with low vertical wind shear, good upper-level outflow and sea surface temperatures near 29 °C (84 °F).

[9] The system's organisation improved steadily over the next few days, and at 12:00 UTC on December 13, the Joint Typhoon Warning Center (JTWC) upgraded the depression to a tropical storm on the Saffir-Simpson hurricane wind scale.

[25] Zazu continued to strengthen even as it began extratropical transition, reaching Category 2 status on the Australian scale on December 15, despite struggling with the effects of westerly wind shear.

[28] Zazu brought heavy surf which severely damaged the wharf on Niue which was recently rebuilt while bringing rainy conditions to the island that same day.

[31] At this stage, the system was poorly organised and lied under the western edge of an upper-level ridge of high pressure in a low to moderate area of vertical windshear.

[33] During January 26, the FMS reported that Tropical Disturbance 05F had developed within the South Pacific convergence zone about 220 km (135 mi) to the northeast of Port Vila in Vanuatu.

[39] The United States Joint Typhoon Warning Center subsequently initiated advisories, on the newly named system and designated it as Tropical Cyclone 15P.

[35] During January 30, Ana continued to move south-southeastwards and passed through the northern Yasawa Islands into the Bligh Waters, where it became slow-moving and intensified into a category 2 tropical cyclone.

[40] The system subsequently continued to develop with an eye feature appearing on both radar and microwave imagery before it made landfall on Viti Levu near Rakiraki at around 18:00 UTC (06:00 FST, January 31).

[40][41][42] While located over Viti Levu, Ana moved south-southeastwards over the Central Division, where it passed in between Navua and Fiji's capital city: Suva.

[43][44] During February 1, the system rapidly weakened into a subtropical low, as its low-level circulation center became exposed and moved south-eastwards into an area of high vertical wind shear.

[43] During January 27, the FMS reported that Tropical Disturbance 06F had developed near the Lau Island of Nayau, about 250 km (155 mi) to the east of Suva, Fiji.

[50] During January 29, the FMS reported that Tropical Disturbance 07F had developed about 700 km (435 mi) to the north-northeast of Port Vila in Vanuatu in a relatively favorable environment with warm sea surface temperatures and low wind shear.

Lucas's LLC became exposed as it weakened to a Category 1 cyclone on the Australian scale and began to undergo subtropical transition just north of New Caledonia on February 2, at which time the JTWC ceased warnings on the storm.

[60][61] A 29-year-old woman and another man drowned off the Gold Coast of Queensland amidst dangerous swells produced by the extratropical remnants of Lucas, their bodies having been recovered on February 9.

At that time, the storm began to weaken due to increasing wind shear and on near-midnight, it skirted the southeastern coast of New Caledonia as a Category 3 severe tropical cyclone.

As the storm approached, New Caledonia was placed on high alert, as Niran was expected to cause severe damage in the country, especially on the main island of Grande Terre.