Tropical Cyclone Yasa Rapidly Intensifies to Equivalent of Major Hurricane

Tropical Cyclone Yasa rapidly intensified into the equivalent of a major hurricane on Tuesday. At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Yasa was located at latitude 14.7°S and longitude 173.8°E which put it about 320 miles (515 km) northwest of Nadi, Fiji. Yasa was moving toward the east at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h). The minimum surface pressure was 922 mb.

Tropical Cyclone Yasa rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale northwest of Fiji on Tuesday. An eye with at diameter of 23 miles (37 km) was at the center of Yasa. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Yasa. Storms near the core generated strong upper level divergence which pumped mass away from the tropical cyclone in all directions.

Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Tropical Cyclone Yasa. Winds to tropical storm force extended out 130 miles (210 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Yasa was 33.3. The Hurricane Size Index (HSI) was 14.8 and the Hurricane Wind Intensity Size Index (HWISI) was 48.1. Tropical Cyclone Yasa was capable of causing regional severe damage.

Tropical Cyclone Yasa will move through an environment favorable for intensification during the next 24 hours. Yasa will be over water where the Sea Surface Temperature is near 29°C. It will be in a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Cyclone Yasa is could strengthen into the equivalent of a Category 5 hurricane during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. If that happens, then an eyewall replacement cyclone could cause Yasa to start to weaken.

Tropical Cyclone Yasa will move around the southwestern part of a high pressure system near the Equator. The high will steer Yasa toward the southeast during the next two days. On its anticipated track Tropical Cyclone Yasa could approach Fiji in 36 hours. Yasa will be the equivalent of a major hurricane when it approaches Fiji. The center of Tropical Cyclone Yasa could pass between Vanua Levu and Viti Levu. Yasa could bring very strong winds and locally heavy rain to the most populated parts of Fiji. Tropical Cyclone Yasa could cause severe damage to Fiji.

Elsewhere over the South Pacific Ocean, the center of Tropical Cyclone Zazu passed southwest of Niue. At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Zazu was located at latitude 20.6°S and longitude 170.7°W which put it about 115 miles (185 km) southwest of Niue. Zazu was moving toward the southeast at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 979 mb.