Tropical Cyclone Harold rapidly intensified into the equivalent of a hurricane/typhoon west-northwest of Vanuatu on Friday. At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Harold was located at latitude 14.1°S and longitude 164.1°E which put it about 170 miles (275 km) west-northwest of Nokuku, Vanuatu. Harold was moving toward the southeast at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 959 mb.
The circulation around Tropical Cyclone Harold organized quickly on Friday. The inner end of a rainband wrapped around the center of circulation and a small eye formed. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Harold. The strongest rainbands were in the eastern half of the circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms around the core of the circulation generated strong upper level divergence which pumped mass away to the east of the tropical cyclone.
Winds to hurricane/typhoon force extend out 35 miles (55 km) from the center of Tropical Cyclone Harold. Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Harold was 17.8. The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 29.8. Harold was capable of causing serious damage.
Tropical Cyclone Harold will move through an environment favorable for intensification during the next 24 to 48 hours. Harold will move over water where the Sea Surface Temperature is near 30°C. It will move around the southwestern part of an upper level ridge over the South Pacific Ocean. The ridge will produce northwesterly winds which will blow toward the top of the circulation. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. Tropical Cyclone Harold will strengthen into the equivalent of a major hurricane during the next 12 hours.
The upper level ridge will steer Tropical Cyclone Harold slowly toward the southeast during the weekend. On its anticipated track Harold will gradually approach Espiritu Santo and Malekula in Vanuatu. The core of Tropical Cyclone Harold could move across the central part of Vanuatu in 48 to 72 hours. Harold is likely to be the equivalent of a major hurricane at that time.
Elsewhere in the tropics, Tropical Cyclone Irondro intensified into the equivalent of a hurricane/typhoon over the South Indian Ocean. At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Irondro was located at latitude 19.9°S and longitude 76.4°E which put it about 885 miles (1425 km) south-southeast of Diego Garcia. Irondro was moving toward the east-southeast at 21 m.p.h. (33 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (170 km/h). The minimum surface pressure was 973 mb.