1977–78 South Pacific cyclone season

Category 1 tropical cyclone (Australian scale)
Tropical storm (SSHWS)
Duration	December 5 – December 11
Peak intensity	75 km/h (45 mph) (10-min); 990 hPa (mbar)

Tessa precursor tropical depression was first noted on December 5, while it was located in the southern Line Islands of Kiribati.[1][2] Over the next couple of days, the system moved southeastwards and gradually intensified, before it was named Tessa by the FMS during December 7.[1]

During December 9, the system moved in between Puka Puka and Reao as it continued to weaken and move south-eastwards towards the Gambier Islands.[1] The system was last noted during December 11, while it was located about 590 km (365 mi) to the northeast of Adams Town in the Pitcarn Islands.[2] As the system moved through the Tuamotu Islands of French Polynesia, Tessa caused significant precipitation over the islands, with the Puka Puka weather station recording a 24-hour rainfall total of 154.2 mm (6.07 in) during December 8.[1]

Category 2 tropical cyclone (Australian scale)
Tropical storm (SSHWS)
Duration	December 23 – December 31
Peak intensity	100 km/h (65 mph) (10-min); 980 hPa (mbar)

For several days during the week building up to Christmas 1977, a tropical disturbance persisted about 925 km (575 mi) to the northeast of Fiji and to the northwest of Samoa.[3] A distinct cyclonic circulation subsequently started to develop during December 23, while it was located about 740 km (460 mi) to the northeast of Vanua Levu. Over the next day the system moved south-westwards and passed within 75 km (45 mi) of Futuna, before it was named Anne by the FMS during December 24, as satellite pictures showed that a tropical cyclone was developing. During December 25, the winds were indirectly estimated to be off gale-force, as it passed south-westwards through the Fijian Islands.

Category 2 tropical cyclone (Australian scale)
Duration	February 15 – February 22
Peak intensity	100 km/h (65 mph) (10-min); 980 hPa (mbar)

During February 15, a tropical depression developed within the South Pacific Convergence Zone, to the west of French Polynesia's Society Islands.[1][4] Over the next couple of days, the system moved eastwards towards Mopelia while gradually developing further, before it was named Diana by the FMS during February 16.[1]

Category 2 tropical cyclone (Australian scale)
Tropical storm (SSHWS)
Duration	February 17 – February 23
Peak intensity	100 km/h (65 mph) (10-min); 980 hPa (mbar)

During February 17, the FMS started to monitor a tropical depression that had developed, about 560 km (350 mi) to the northwest of Udu Point in Fiji.[3] During that day, the system deepened as it moved south-eastwards towards Fiji before the FMS named it Ernie.[3]