Tropical Depression 04F

During December 12, the FMS reported that Tropical Disturbance 04F had developed about 105 km (65 mi) to the northeast of Rotuma, Fiji.^[6]

Tropical Depression 05F

A tropical disturbance formed east of island Fiji.It had developed into the tropical depression during 22 December. It moved westwards and dissipated 26 December.^{[citation needed]}

Tropical Depression 09F

During February 5, the FMS reported that Tropical Disturbance 09F had developed within a trough of low pressure, about 210 km (130 mi) to the south-southwest of the Fiji's capital city: Suva.^[7][8] During that day the system moved south-eastwards away from Fiji, before it moved back towards the island nation and passed over the southern Fijian islands between February 6–9.^[8]

Tropical Depression 10F

A tropical depression developed east of Vanuatu on February 7. It strengthened and reached peak intensity over the early hours of February 8. At the time, the depression made landfall on the islands over the territory of New Caledonia. It rapidly weakened until it degenerated to a remnant low on the late hours of December 9. The FMS will continue monitor it until the early hours of February 11, when it completely succumbed with the remnants of Tropical Depression 11F.^{[citation needed]}

Tropical Depression 11F

A tropical depression developed over the Coral Sea on February 9. It rapidly intensified until it had peak intensity on the early hours of February 10. It rapidly weakened and FMS discontinued advisories on the system on the early hours of February 11, and the system moved slowly southwest until it dissipated on February 12.^{[citation needed]}

Tropical Depression 13F

A tropical depression developed over French Polynesia on February 15. It intensified until it reached peak intensity over the south Pacific on February 16. It later undergo extratropical transition, a process that will be completed on the late hours of February 18.^{[citation needed]}

Tropical Depression 14F

A tropical depression developed between Vanuatu to the east and Fiji to the west on February 16.^{[citation needed]} The initially disorganized system intensified until it reached its initial peak intensity of 45 knots while accelerating north.^[9] Immediately after, however, strong shear weakened the system, causing it to become disorganized again.^{[citation needed]} On February 20, the system began to organize again, and the JTWC upgraded the system to Tropical Cyclone 08P as it neared landfall on Fiji before crossing the International Date Line. The cyclone later reached its secondary peak intensity of 40 knots before it underwent extratropical transition, a process that completed during the early hours of February 23.^[9]

Tropical Cyclone Bart

During February 19, the FMS reported that Tropical Disturbance 15F had developed, about 300 km (185 mi) to the southwest of Apia, Samoa.^[10] Over the next couple of days, the system gradually developed further and became a tropical depression, as it moved south-eastwards within an area of low vertical wind shear.^[11] During February 21, the JTWC initiated advisories and designated it as Tropical Cyclone 07P, after an ASCAT satellite image had revealed the presence of 65–75 km/h (40–45 mph) winds, within its partially exposed circulation.^[12] The FMS subsequently named the system Bart as it had become a Category 1 tropical cyclone on the Australian scale, with peak 10-minute sustained wind speeds of 75 km/h (45 mph).^[13][14] After it had been named, Bart continued to move south-eastwards and passed to the west of the Southern Cook Islands, before it entered MetService's area of responsibility early on February 22.^[14][15] During that day, the system gradually transitioned and was reclassified as an extratropical cyclone, before it continued to weaken and dissipated over open seas.^[14] Gale-force winds, rain and thunderstorms were observed over the Southern Cook Islands, but there was no significant impact reported.^[15]

Tropical Depression 19F

Tropical Disturbance 19F was first noted on April 1, while it was located about 240 km (150 mi) to the northeast of Pago-Pago, in American Samoa.^[16] The system was poorly organised at this stage and lied within an upper-level monsoonal trough of low pressure in a moderate area of vertical wind shear.^[16] It existed for a very long period of time as it moved slowly, and ties Typhoon Noru for the longest lasting storm in 2017.

Severe Tropical Cyclone Cook

Tropical Disturbance 20F was first noted during April 5, while it was located about 200 km (125 mi) to the northwest of the Fijian dependency of Rotuma.^[17] Over the next couple of days, the disturbance moved south-westwards and gradually developed further, before it was classified as a tropical depression by the FMS during April 7. The system subsequently continued to move south-westwards and passed near to or over the islands of Maewo, Ambae and Malakula in northern Vanuatu. As the system impacted Vanuatu, the JTWC and the FMS reported that the system had developed into a tropical cyclone, with the latter naming it as Cook.^[15][18] After Cook was named, the cyclone steadily intensified further and developed a 30 km (20 mi) eye, as it moved south-westwards towards New Caledonia.^[19] The FMS subsequently reported during April 9, that the system had become a Category 3 severe tropical cyclone, with peak 10-minute sustained winds of 155 km/h (95 mph).^[20] The JTWC subsequently reported that the cyclone had peaked with 1-minute sustained wind speeds of 165 km/h (105 mph), which made it equivalent to a Category 2 hurricane. Cook subsequently passed over New Caledonia during April 10, before it started to move southwards towards New Zealand and transition into an extratropical cyclone as it moved southwards towards New Zealand. The system was subsequently declared extratropical by both MetService and the JTWC during April 11, before it made landfall on New Zealand's North Island during April 13.^[21] After making landfall, the system moved south-southwest and moved to the east of the South Island during the following day before they were last noted during April 17.^[14]

Severe Tropical Cyclone Donna

Cyclone Donna was the strongest off-season South Pacific tropical cyclone on record during the month of May.^[22] Donna formed from an area of disturbed weather that was first monitored west-northwest of Fiji on 1 May 2017. The disturbance drifted eastward amid an increasingly favorable environment, and it was designated Tropical Depression 21F late on 2 May. Twelve hours later, it intensified into a Category 1 on the Australian tropical cyclone scale and was designated Tropical Cyclone Donna as the storm's motion shifted west and then south. After reaching its initial peak as a Category 4 cyclone early on 6 May, the effects of wind shear and upwelling caused the storm to weaken. However, it reintensified into a Category 5 cyclone on 8 May. Soon after, Donna entered a region of strong westerly flow and began to rapidly weaken. Continuing to accelerate in a southerly direction, Donna eventually weakened into a tropical low on 10 May. By 16 May, Donna's remnants had fully dissipated.^{[citation needed]}

Tropical Cyclone Ella

During May 7, the FMS started to monitor Tropical Disturbance 22F that had developed within a trough of low pressure about 470 km (290 mi) to the northeast of Suva, Fiji. Amid generally favorable environmental conditions, Tropical Depression 22F developed southwest of American Samoa on 9 May.^[23] Just three hours later, the system intensified into a Category 1 tropical cyclone on the Australian scale, and was named Ella by the Fiji Meteorological Service (FMS).^[24]

Other systems

During November 12, the first tropical disturbance, Tropical Disturbance 01F, of the season developed, about 300 km (185 mi) to the northeast of the island nation, Niue.^[25] 01F was poorly organised and over the next day atmospheric convection surrounding the system significantly decreased as it moved south-eastwards, within an area of moderate to high vertical wind shear.^[25][26] As a result, 01F was subsequently last noted during November 13, as it was not expected to develop into a tropical cyclone.^[26] Tropical Disturbance 02F subsequently developed during November 23, around 300 km (185 mi) to the northeast of Pago Pago in American Samoa.^[27] Over the next few days, the system remained poorly organised as it slowly moved south-eastwards, before the FMS reported that 02F was not expected to develop into a tropical cyclone and issued its last advisory on the system.^[28] During November 26, the third tropical disturbance of the season moved into the basin from the Australian region, while it was located about 820 km (510 mi) to the northwest of Nouméa, New Caledonia.^[29] Over the next couple of days, 03F moved eastwards towards Vanuatu and remained poorly organised, before the FMS issued its last advisory on the system during November 30.^[30]

During the first half of January 2017, Tropical Disturbances 06F, 07F and 08F developed in quick succession. Tropical Disturbance 06F developed over the Solomon Islands on 2 January, and dissipated four days later. Tropical Disturbances 07F and 08F both formed on 10 January. The former meandered around French Polynesia before it dissipated on 20 January, while the latter degenerated within 24 hours near Fiji. Tropical Disturbance 12F developed over Fiji on February 15, and moved around the archipelago erratically for the next nine days before dissipating. On February 23, Tropical Disturbance 16F formed well to the east of Vanuatu, and stalled there for the next few days before dissipating on February 26.^{[citation needed]}

On March 4, Tropical Disturbance 17F developed in roughly the same region as its predecessor 16F. However, it dissipated just one day later.^{[citation needed]} Tropical Disturbance 18F developed along a pre-frontal trough of low pressure during March 18, about 455 km (285 mi) to the north of Suva, Fiji.^[31] Over the next couple of days, the system and associated trough of low pressure, moved south-eastwards towards Tonga, before the disturbance was last noted during March 21.^[31][32] Cloud bands associated with the trough brought heavy rain and flooding to the Northern Division.^[31]

Retirement

After the season, the names Cook and Donna were both retired, and replaced with Crystal and Dean respectively. ^[33]