1989–90 South Pacific cyclone season

Tropical Depression Felicity

On December 19, the remnants of Tropical Cyclone Felicity, moved into the basin with 10-minute sustained windspeeds of 75 km/h (45 mph), which would have made it a category 1 tropical cyclone on the Australian scale. However, because it did not have the "classical characteristics of a tropical cyclone", it was treated as a tropical depression by the BoM and the FMS. Over the next couple of days, in response to an upper level trough of low pressure weakening, the depression slowly weakened further, while accelerating to towards the southeast. Felicity was absorbed by a short-wave trough of low pressure to the north of New Zealand before it was last noted during December 22.

Coral Sea Depression

On January 20, TCWC Nadi started to monitor a shallow area of low pressure that had developed within a trough of low pressure, about 600 mi (965 km) to the Northwest of Noumea in New Caledonia.

The depression was last noted on January 25, as it moved into TCWC Wellington's area of responsibility.

There were no reports of any damage associated with this depression within New Caledonia, which was largely due to its small and not so intense nature of the system.

Severe Tropical Cyclone Ofa

On January 27, a shallow tropical depression formed within the South Pacific Convergence Zone, about 430 km (265 mi) to the southeast of Funafuti, Tuvalu. Over the next two days the system developed little and remained slow moving, near the Tuvaluan atoll of Funafuti. During January 30, the depression moved towards the north-east and started to organize, as pressures near the systems center rapidly falling. During the next day the system subsequently started to curve south-eastwards and away from Tuvalu, before the NWOC initiated advisories on the system and designated it as Tropical Cyclone 13P. Late on January 31, TCWC Nadi named the tropical depression Ofa, after it had developed into a category 1 tropical cyclone on the Australian scale. Over the few days the system moved towards the south-southeast and intensified further. Ofa subsequently passed about 110 km (70 mi) to the west of the Western Samoan Island of Savai'i between 10:00 and 18:00 UTC during February 3. Early the next day as the system started to accelerate towards the south-southeast towards the island nation of Niue, the NWOC estimated that Ofa had peaked with 1-minute sustained wind speeds of 215 km/h (130 mph), which made it equivalent to a category 4 hurricane on the SSHWS. Later that day TCWC Nadi also estimated that the system had peaked with 10-minute sustained wind speeds of 185 km/h (115 mph) as a category 4 severe tropical cyclone,. During February 5, the system passed about 55 km (35 mi) to the west of Niue, as it started to weaken and started to transition into an extratropical cyclone. The system completed this transition during February 8, before the remnants were last noted during February 10 after they had performed a small clockwise loop.

Cyclone Ofa affected seven different island nations and caused gales or much stronger winds in six of those countries which resulted in damage ranging from moderate to very severe. Storm tide from the cyclone which is the combined effect of storm surge and high tide caused havoc in several countries and was the major cause of destruction. Overall the system killed at least eight people while it was estimated that the overall damage would amount to over 7008180000000000000♠US$180 million with damage totals of at least 7008150000000000000♠US$150 million and 7007300000000000000♠US$30 million in Western and American Samoa.

Tropical Cyclone Nancy

Late on January 30, TCWC Nadi started to issue warnings on a tropical depression, that was intensifying as it moved southeastwards and approached 160°E and the South Pacific tropical cyclone basin. The system subsequently moved into the basin early the next day and was named Nancy by TCWC Nadi, after it had become a category 1 tropical cyclone. During that day the system re-curved and started to move towards the south-southwest, as it was steered around the southern extension of an upper level trough of low pressure. The system subsequently moved out of the basin during February 1, as it intensified into a category 2 tropical cyclone. While the system was in the basin the JTWC estimated that Nancy had peak 1-minute sustained winds of 215 km/h (130 mph), which made it equivalent to a category 1 hurricane on the SSHWS. The system subsequently re-entered the basin as an extratropical cyclone on February 6, before it dissipated to the west of New Zealand on February 8. There was no damage associated with Nancy while it was in the basin, however it later caused 5 deaths, when it affected the Australian states of Queensland and New South Wales.

Samoa Depression

On February 6, the FMS reported that a depression had developed, within the South Pacific Convergence Zone near the islands of Tuvalu. Over the next few days the system was steered towards the southeast by a north-westerly steering flow on the eastern side of an upper level trough of low pressure. As the depression moved towards the southeast it passed in between Western Samoa and the northern islands of Tonga before it came very close to Niue during February 8. Despite marginal gale-force winds being present in the depressions eastern quadrant, strong north-westerlies prevented the depression, from strengthening into a tropical cyclone. The depression was subsequently last noted during February 9, as it was absorbed into the Westerlies. The only damage that could be attributed to the depression is a number of houses that were destroyed on the Tuvaluan atoll of Vaitupu on February 6, however it is possible that the houses were destroyed by the strong and squally north-westerlies that were prevailing over the northern islands of Tuvalu at that time. As Tuvalu, Western Samoa, American Samoa, Tonga, Niue had all been affected by Cyclone Ofa a few days earlier; any damage would have been difficult to assess.

Tropical Cyclone Rae

On March 16, TCWC Nadi started to monitor a shallow tropical depression that had developed within the South Pacific Convergence Zone, about 250 mi (400 km) to the west of the Tuvaluan Islands. The system initially moved slowly towards the south — southeast and passed about 60 mi (97 km) to the east of the Fijian Dependency of Rotuma during March 18. Over the next 24 hours the system moved southwards before it turned towards the southwest during March 19, as it approached and started to affect the Fijian Islands. At this time the depression appeared disorganised in satellite imagery, with estimated sustained windspeeds of between 35 to 55 km/h (20 to 35 mph) in a broad area to the north and east of the depression center. During the next day the depression passed about 40 mi (64 km) to the west of the Yasawa group of islands as it continued to move towards the southwest.

Other systems

The following depressions were also monitored by TCWC Nadi, however these systems were either short lived or did not develop significantly. Between November 8–10 and December 14–17, TCWC Nadi monitored 2 depressions that had developed near the Southern Cook Islands and the Samoan Islands. On March 15, the precursor shallow tropical depression to Cyclone Ivor developed within the South Pacific convergence zone, about 390 km (240 mi) to the northeast of Port Villa in Vanuatu. During that day, the low moved towards the southwest and moved into the Australian region where it developed into Tropical Cyclone Ivor during March 16.

Season effects

This table lists all the storms that developed in the South Pacific basin during the 1989–90 season. It includes their intensity on the Australian Tropical cyclone intensity scale, duration, name, areas affected, deaths, and damages.