Category Archives: South Pacific

Tropical Low Strengthens over Gulf of Carpentaria

A tropical low strengthened over the Gulf of Carpentaria on Saturday. At 1:00 p.m. EST on Saturday the center of the tropical low was located at latitude 15.8°S and longitude 138.5°E which put it about 75 miles (120 km) northwest of Mornington Island. The tropical low was moving toward the southeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 998 mb.

A Watch was in effect for the portion of the coast from the border between the Northern Territory and Queensland to Pormpuraaw. The Watch included Mornington Island.

The circulation around the tropical low exhibited better organization on Saturday. More thunderstorms developed near the center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical low. The removal of mass was causing the surface pressure to decrease. Bands of showers and thunderstorms were revolving around the center of the tropical low.

The tropical low will move through an environment favorable for intensification during the next 24 hours. The tropical low will move over water where the Sea Surface Temperature is near 30°C. It will move under the axis of an upper level ridge where the winds are weak. There will be little vertical wind shear. The tropical low will strengthen during the next 24 hours and it is likely to intensify to the equivalent of a tropical storm.

The tropical low will move south of a high pressure system centered north of Australia. The high will steer the tropical low toward the southeast during the next 24 hours. On its anticipated track the tropical low will make landfall on the coast of Queensland between Karumba and Gilbert River Mouth in about 24 hours. It will be the equivalent of a tropical storm when it makes landfall. The tropical low could stall when it moves inland, which would cause a prolonged period of heavy rain. Flash floods could occur in parts of northern Queensland.

Tropical Cyclone Yasa Passes West of Tonga

Tropical Cyclone Tonga passed west of Tonga on Friday. At 4:00 p.m. EST on Friday the center of Tropical Cyclone Yasa was located at latitude 20.6°S and longitude 178.0°W which put it about 280 miles (305 km) west of Nuku’Alofa, Tonga. Yasa was moving toward the south at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 974 mb.

After making a direct hit on Vanua Levu, Tropical Cyclone Yasa moved over the Fiji islands in the Lau Group. There were reports of damage and casualties from Fiji. Tropical Cyclone Yasa weakened after it made landfall on Vanua Levu. The eye and eyewall were disrupted by passage over land. An upper level low centered north of New Zealand produced northerly winds which blew toward the top of Yasa’s circulation on Friday. Those winds caused moderate vertical wind shear and the shear caused the tropical cyclone to weaken steadily on Friday.

The circulation around Tropical Cyclone Yasa exhibited less organization on Friday. The strongest thunderstorms were occurring in a band in the southern half of the circulation. Bands in the northern half of Yasa consisted primarily of showers and lower clouds. The circulation around Tropical Cyclone Yasa was still large. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation.

Tropical Cyclone Yasa will move through an environment that is mostly unfavorable for intensification during the next several days. Yasa will move over water where the Sea Surface Temperature is near 27°C. However, the upper level low centered north of New Zealand will continue to cause moderate vertical wind shear. The shear is likely to be strong enough to cause Tropical Cyclone Yasa to continue to weaken.

Tropical Cyclone Yasa will move around the eastern side of the upper level low. The low will steer Yasa toward the southwest during the next 48 hours. On its anticipated track Tropical Cyclone Yasa will pass west of Tonga and it will remain north of New Zealand.

Severe Tropical Cyclone Yasa Hits Fiji

Severe Tropical Cyclone Yasa hit Fiji early on Thursday. At 4:00 a.m. EST on Thursday the center of Tropical Cyclone Yasa was located at latitude 16.8°S and longitude 179.2°E which put it about 30 miles (50 km) south of Naduri, Fiji. Yasa was moving toward the east-southeast at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 922 mb.

The eye of Tropical Cyclone Yasa made landfall in Fiji on Vanua Levu west of Naduri early on Thursday. Yasa was a large, powerful tropical cyclone when it hit Fiji. Tropical Cyclone Yasa was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale at the time of landfall. Winds to hurricane/typhoon force extended out 65 miles (105 km) from the center of Yasa. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Yasa was 31.6. The Hurricane Size Index (HSI) was 23.1 and the Hurricane Wind Intensity Size Index (HWISI) was 54.7. Yasa was capable of causing severe damage.

Tropical Cyclone Yasa brought destructive winds to Vanua Levu when the core of the circulation passed over that island. Severe wind damage was likely. Yasa was capable of causing a storm surge of up to 15 feet (5 meters) on the north coast of Vanua Levu. It was also dropping heavy rain and flash floods were likely. Bands in the western half of Tropical Cyclone Yasa caused strong winds and heavy rain over the eastern part of Viti Levu. Widespread power outages were likely.

Tropical Cyclone Yasa will move toward the southeast over the islands in the Lau Group later on Thursday. Yasa will weaken as it crosses Vanua Levu, but it will still be a strong tropical cyclone. Tropical Cyclone Yasa could cause serious wind damage and cause flash floods on many of the islands in the Lau Group.

Tropical Cyclone Yasa Strengthens to Equivalent of Cat. 5 Hurricane

Tropical Cyclone Yasa strengthened to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday night. At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Yasa was located at latitude 14.6°S and longitude 174.5°E which put it about 285 miles (460 km) northwest of Nadi, Fiji. Yasa was moving toward the east at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h). The minimum surface pressure was 915 mb.

Tropical Cyclone Yasa intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale northwest of Fiji on Tuesday night. An eye with at diameter of 35 miles (55 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 50 miles (80 km) from the center of Tropical Cyclone Yasa. Winds to tropical storm force extended out 160 miles (260 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Yasa was 35.0. The Hurricane Size Index (HSI) was 19.3 and the Hurricane Wind Intensity Size Index (HWISI) was 54.3. Tropical Cyclone Yasa was capable of causing regional catastrophic damage.

Tropical Cyclone Yasa will move through an environment capable of sustaining an intense tropical cyclone 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 will remain an intense tropical cyclone 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 36 hours. On its anticipated track Tropical Cyclone Yasa could reach Fiji in less than 36 hours. Yasa will be the equivalent of a major hurricane when it approaches Fiji. The center of Tropical Cyclone Yasa could pass over Vanua Levu. Yasa could bring very strong winds and locally heavy rain to the some of 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 was moving away from of Niue. At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Zazu was located at latitude 21.7°S and longitude 169.6°W which put it about 130 miles (210 km) south of Niue. Zazu was moving toward the southeast at 14 m.p.h. (22 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.

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.

Tropical Cyclone Yasa Intensifies Northwest of Fiji

Tropical Cyclone Yasa intensified northwest of Fiji on Monday. At 10:00 p.m. EST on Monday the center of Tropical Cyclone Yasa was located at latitude 14.9°S and longitude 172.5°E which put it about 350 miles (565 km) west-northwest of Nadi, Fiji. Yasa was moving toward the northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 961 mb.

Tropical Cyclone Yasa intensified into the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale northwest of Fiji on Monday. A circular eye with a diameter of 25 miles (40 km) developed 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 center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical cyclone. Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Tropical Cyclone Yasa. Winds to tropical storm force extended out 150 miles (240 km) from the center.

Tropical Cyclone Yasa will move through an environment favorable for intensification during the next 36 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 likely to intensify into the equivalent of a major hurricane during the next 24 hours.

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 several days. On its anticipated track Tropical Cyclone Yasa could approach Fiji in 48 hours. Yasa is very likely to be the equivalent of a major hurricane when it approaches Fiji.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Zazu continued to bring wind and rain to the Vava’u Group of Islands in Tonga. A weather station at Lupepau’u airport in Vava’u reported at sustained wind speed of 45 m.p.h. (75 km/h) and a wind gust of 60 m.p.h. (95 km/h). At 10:00 p.m. EST on Monday the center of Tropical Cyclone Zazu was located at latitude 19.0°S and longitude 173.7°W which put it about 30 miles (50 km) south-southeast of Neiafu, Tonga. Zazu was moving toward the southeast at 4 m.p.h. (6 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 982 mb.

Tropical Cyclone Zazu Brings Wind and Rain to Northern Tonga

Tropical Cyclone Zazu brought wind and rain to northern Tonga on Monday. At 10:00 a.m. EST on Monday the center of Tropical Cyclone Zazu was located at latitude 18.9°S and longitude 174.4°W which put it about 40 miles (65 km) west of Neiafu, Tonga. Zazu was moving toward the south-southwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 991 mb.

Tropical Cyclone Zazu brought wind and rain to the Vava’u Group of islands in northern Tonga on Monday. The circulation around Zazu was intensifying. The inner end of a rainband wrapped partly around the eastern side of the center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical cyclone. Thunderstorms were occurring in bands in the eastern half of Tropical Cyclone Zazu. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 150 miles (240 km) on the eastern side of Zazu. Winds to tropical storm force extended out 75 miles (120 km) in the western half of the circulation.

Tropical Cyclone Zazu will move through an environment favorable for intensification during the next 24 hours. Zazu will move over water where the Sea Surface Temperature is near 29°C. It will move south of an upper level trough over the South Pacific Ocean. The trough will produce westerly winds which will blow toward the top of Zazu. Those winds will cause some vertical wind shear and they are contributing to the asymmetrical distribution of thunderstorms. The shear will inhibit intensification of Tropical Cyclone Zazu, but the shear will not be strong enough to prevent Zazu from intensifying. Tropical Cyclone Zazu could strengthen into the equivalent of a hurricane/typhoon during the next 24 hours. The vertical wind shear will increase in a day or so, and Zazu will start to weaken when that happens.

The upper level trough will start to steer Tropical Cyclone Zazu toward the southeast during the next 24 hours. On its anticipated track Zazu will move between Tonga and Niue. Tropical Cyclone Zazu will continue to cause gusty winds and heavy rain over parts of Tonga during the next 24 hours. Rainbands on the eastern side of Zazu could affect Niue on Tuesday.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Yasa strengthened to the equivalent of a hurricane/typhoon west-northwest of Fiji. At 10:00 a.m. EST on Monday the center of Tropical Cyclone Yasa was located at latitude 15.5°S and longitude 171.6°E which put it about 400 miles (640 km) west-northwest of Nadi, Fiji. Yasa was moving toward the north-northwest at 3 m.p.h. (5 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 976 mb. Tropical Cyclone Yasa is forecast to move toward Fiji and to intensify into the equivalent of a major hurricane.

Tropical Cyclone Yasa Strengthens between Fiji and Vanuatu

Tropical Cyclone Yasa strengthened between Fiji and Vanuatu on Sunday. At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Yasa was located at latitude 15.7°S and longitude 172.1°E which put it about 380 miles (610 km) west-northwest of Nadi, Fiji. Yasa was moving toward the west-southwest at 4 m.p.h. (6 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 982 mb.

Tropical Cyclone Yasa strengthened on Sunday after the circulation of former Tropical Cyclone 04P was absorbed by the larger circulation around Yasa. The inner end of a rainband wrapped around the eastern side of the center of circulation. Other bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Yasa. Storms near the center generated upper level divergence which pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation.

Tropical Cyclone Yasa will be in an environment favorable for intensification during the next several days. 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 will likely intensify into the equivalent of a hurricane/typhoon during the next 18 hours. It could strengthen to the equivalent of a major hurricane in about three days.

Tropical Cyclone Yasa will be in an area where the steering winds are weak during the next 24 hours. Yasa is forecast to make a slow clockwise loop during the next 24 to 36 hours. Eventually, a high pressure system over the South Pacific Ocean will start to steer Tropical Cyclone Yasa toward the southeast. On its anticipated track Tropical Cyclone Yasa could approach Fiji in about four days.

Elsewhere over the South Pacific Ocean, Tropical Cyclone 06P developed north of Tonga. At 4:00 p.m. EST on Sunday the center of Tropical Cyclone 06P was located at latitude 17.8°S and longitude 173.9°W which put it about 60 miles (95 km) north of Neiafu, Tonga. It was moving toward the south-southwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 997 mb.

Tropical Cyclone Developing East of Vanuatu

A tropical cyclone was developing east of Vanuatu on Friday night. The large low pressure system contained two smaller circulation. One circulation was already designated at Tropical Cyclone 04P by the Joint Typhoon Warning Center. At 10:00 p.m. EST on Friday the center of Tropical Cyclone 04P was located at latitude 14.9°S and longitude 175.8°E which put it about 220 miles (360 km) north-northwest of Nadi, Fiji. It was moving toward the west-southwest at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 994 mb.

A second larger circulation designated Invest 91P was located northwest of Tropical Cyclone 04P. At 10:00 p.m. EST on Friday the center of Invest 91P was located at latitude 12.6°S and longitude 170.1°E which put it about 310 miles (500 km) east-northeast of Vanuatu. It was moving toward the east at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1002 mb.

Tropical Cyclone 04P and Invest 91P will rotate around each other during the next several days. The circulation around Invest 91P was larger, but the wind speeds were weaker. Upper level divergence from Invest 91P was creating vertical wind shear over Tropical Cyclone 04P. The shear was inhibiting the intensification of Tropical Cyclone 04P. The two circulations are forecast to eventually merge, but numerical models differ on which circulation will become the dominant center of circulation.

The larger environment around Tropical Cyclone 04P and Invest 91P will be favorable for intensification after the two circulations merge. The merged tropical cyclone 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. Once Tropical Cyclone 04P and Invest 91P consolidate into a single circulation, then the tropical cyclone will intensify. It could strengthen into the equivalent of a hurricane/typhoon early next week.

Tropical Cyclone 04P and Invest 91P will rotate clockwise around each other during the weekend. The overall circulation containing the two systems is forecast to drift slowly toward the south during the next several days. On its forecast track the developing tropical cyclone will move slowly toward the south between Fiji and Vanuatu.

Tropical Cyclone Harold Brings Wind and Rain to Tonga

Tropical Cyclone Harold brought wind and rain to Tonga on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Harold was located at latitude 23.8°S and longitude 172.1°W which put it about 250 miles (400 km) southeast of Nuku Alofa, Tonga.  Harold was moving toward the east-southeast at 30 m.p.h. (50 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 945 mb.

After forming near the Solomon Islands and causing damage in Vanuatu and Fiji, Tropical Cyclone Harold brought gusty winds and locally heavy rain to portions of Tonga on Wednesday.  The core of Harold with the strongest winds passed about 60 miles (95 km)  southwest of Tongatapu.  However, winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation.  An airport at Fua’amotu, Tonga reported a sustained wind speed of 58 m.p.h. (93 km/h) when Harold passed southwest of its location.  The airport also reported a wind gust of 89 m.p.h. (143 km/h).

Tropical Cyclone Harold moved quickly away from Tonga on Wednesday night.  Weather conditions were improving.  A high pressure system over the South Pacific Ocean will continue to steer Harold rapidly toward the east-southeast during the next several days.  On its anticipated track Tropical Cyclone Harold will pass well to the south of Niue.

Tropical Cyclone Harold will move into a less favorable environment.  Harold will move under 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 moderate vertical wind shear.  Harold will also move over cooler water.  Moderate vertical wind shear and cooler water will cause Tropical Cyclone Harold to weaken.  Harold could eventually make a transition to an extratropical cyclone when it moves out of the tropics.