On April 1, the Australian Bureau of Meteorology (BOM) reported that Tropical Low 12U had developed along a trough of low pressure about 825 km (515 mi) to the northeast of Port Moresby in Papua New Guinea.
The disturbance initially displayed a broad low-level circulation and scattered atmospheric convection, but it was located within a favourable environment for further development, with developing dual-channel outflow, low vertical wind shear, and warm sea surface temperatures of 30 °C (86 °F).
Thunderstorm activity began to coalesce about the centre later that day, and a nearby upper-level low directed the system southeast toward the Solomon Islands.
Given the increase in organization, the BOM upgraded the storm to a Category 1 tropical cyclone on the Australian tropical cyclone intensity scale and named it Harold, before it passed about 135 km (85 mi) to the southeast of Honiara in the Solomon Islands.
The United States Joint Typhoon Warning Center (JTWC) also initiated advisories on Tropical Cyclone Harold during that day and designated it as Tropical Cyclone 25P. The system subsequently crossed 160°E, where it moved out of the Australian region and into the South Pacific basin, which prompted the BoM to pass the primary warning responsibility to the Fiji Meteorological Service (FMS).

As the storm moved away from the Solomon Islands on April 3, it began to rapidly organize and developed a pinhole eye on microwave imagery.
As a result, it was classified as a Category 3 severe tropical cyclone by the FMS at 00:00 UTC on April 4.
At this time, Harold was located about 360 km (225 mi) to the northwest of Luganville in Vanuatu, and its southeast movement had slowed significantly as a result of an extension of a subtropical ridge to the storm's east.
Later that day, the FMS reported that Harold had become a Category 4 severe tropical cyclone and predicted it to further intensify to Category 5 status, while the system's eye became subsumed into a large mass of atmospheric convection.
The JTWC, meanwhile, assessed that Harold 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 Saffir-Simpson hurricane wind scale (SSHWS).
During April 5, the JTWC reported that the system had begun to weaken, based on the ragged structure of the eye and warming of the cyclone's cloud tops.
However, this weakening phase was short-lived as the system regained a 30 km (20 mi) eye and a symmetric central dense overcast, while upper-level outflow remained strong.
The FMS subsequently reported that Harold had become a Category 5 severe tropical cyclone with 10-minute sustained winds of 205 km/h (125 mph).
At this time, the system was located about 170 km (105 mi) to the west of Luganville and began to move polewards as a subtropical ridge to its northeast became the primary steering mechanism.

At around 22:00 UTC on April 5 (10:00 FST, April 6), Harold made landfall on the island of Espiritu Santo in northern Vanuatu, with 10-minute sustained winds of 215 km/h (130 mph).
During the following day, the FMS reported that Harold had peaked in intensity with 10-minute sustained winds of 230 km/h (145 mph), while it was located between the islands of Espiritu Santo and Pentecost.
The system subsequently made landfall on Pentecost, before it reemerged into the South Pacific Ocean and started to move away from Vanuatu.
The JTWC then reported that the system had again peaked in intensity and assessed 1-minute sustained wind speeds of 270 km/h (165 mph), which made it equivalent to a Category 5 hurricane on the SSHWS.
After it had peaked in intensity, Harold started to show signs of weakening: its eye became cloud-filled, cloud tops warmed, convection reduced in extent, and dry air started to wrap into the system.
As a result, the FMS reported that the system had weakened into a Category 4 severe tropical cyclone during April 7, before Harold's eye and eyewall became visible on their radar in Nadi.
The system subsequently passed within 115 km (70 mi) of Suva in Fiji, before it passed
On April 1, the Australian Bureau of Meteorology (BOM) reported that Tropical Low 12U had developed along a trough of low pressure about 825 km (515 mi) to the northeast of Port Moresby in Papua New Guinea. The disturbance initially displayed a broad low-level circulation and scattered atmospheric convection, but it was located within a favourable environment for further development, with developing dual-channel outflow, low vertical wind shear, and warm sea surface temperatures of 30 °C (86 °F). Thunderstorm activity began to coalesce about the centre later that day, and a nearby upper-level low directed the system southeast toward the Solomon Islands. Given the increase in organization, the BOM upgraded the storm to a Category 1 tropical cyclone on the Australian tropical cyclone intensity scale and named it Harold, before it passed about 135 km (85 mi) to the southeast of Honiara in the Solomon Islands. The United States Joint Typhoon Warning Center (JTWC) also initiated advisories on Tropical Cyclone Harold during that day and designated it as Tropical Cyclone 25P. The system subsequently crossed 160°E, where it moved out of the Australian region and into the South Pacific basin, which prompted the BoM to pass the primary warning responsibility to the Fiji Meteorological Service (FMS).
As the storm moved away from the Solomon Islands on April 3, it began to rapidly organize and developed a pinhole eye on microwave imagery. As a result, it was classified as a Category 3 severe tropical cyclone by the FMS at 00:00 UTC on April 4. At this time, Harold was located about 360 km (225 mi) to the northwest of Luganville in Vanuatu, and its southeast movement had slowed significantly as a result of an extension of a subtropical ridge to the storm's east. Later that day, the FMS reported that Harold had become a Category 4 severe tropical cyclone and predicted it to further intensify to Category 5 status, while the system's eye became subsumed into a large mass of atmospheric convection. The JTWC, meanwhile, assessed that Harold 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 Saffir-Simpson hurricane wind scale (SSHWS). During April 5, the JTWC reported that the system had begun to weaken, based on the ragged structure of the eye and warming of the cyclone's cloud tops. However, this weakening phase was short-lived as the system regained a 30 km (20 mi) eye and a symmetric central dense overcast, while upper-level outflow remained strong. The FMS subsequently reported that Harold had become a Category 5 severe tropical cyclone with 10-minute sustained winds of 205 km/h (125 mph). At this time, the system was located about 170 km (105 mi) to the west of Luganville and began to move polewards as a subtropical ridge to its northeast became the primary steering mechanism.
At around 22:00 UTC on April 5 (10:00 FST, April 6), Harold made landfall on the island of Espiritu Santo in northern Vanuatu, with 10-minute sustained winds of 215 km/h (130 mph). During the following day, the FMS reported that Harold had peaked in intensity with 10-minute sustained winds of 230 km/h (145 mph), while it was located between the islands of Espiritu Santo and Pentecost. The system subsequently made landfall on Pentecost, before it reemerged into the South Pacific Ocean and started to move away from Vanuatu. The JTWC then reported that the system had again peaked in intensity and assessed 1-minute sustained wind speeds of 270 km/h (165 mph), which made it equivalent to a Category 5 hurricane on the SSHWS. After it had peaked in intensity, Harold started to show signs of weakening: its eye became cloud-filled, cloud tops warmed, convection reduced in extent, and dry air started to wrap into the system. As a result, the FMS reported that the system had weakened into a Category 4 severe tropical cyclone during April 7, before Harold's eye and eyewall became visible on their radar in Nadi. The system subsequently passed within 115 km (70 mi) of Suva in Fiji, before it passed
Cyclone Harold