Category Archives: South Pacific

Tropical Low Strengthens Over Gulf of Carpentaria

A Tropical Low designated as Invest 99P by some agencies strengthened over the Gulf of Carpentaria on Saturday.  At 4:00 p.m. EST on Saturday the center of the Tropical Low was located at latitude 14.3°S and longitude 138.2°E which put it about 110 miles (180 km) east of Groote Eylandt, Australia.  The Tropical Low was moving toward the south at 4 m.p.h. (6 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 1000 mb.

The Australian Bureau of Meteorology issued a Warning for the portion of the coast from Numbulwar to Kowanyama including Mornington Island.

More bands of thunderstorms began to develop around a Tropical Low on Saturday.  The bands were revolving around the center of circulation.  The Tropical Low will move through an environment favorable for intensification during the next 24 hours.  It will move over water where the Sea Surface Temperature is near 30°C.  The Tropical Low is under an upper level ridge and the upper level winds are weak.  There will be little vertical wind shear and the Tropical Low is forecast to strengthen into a tropical cyclone.

The Tropical Low will move around the western end of a high pressure system.  The high will steer the Low toward the south.  On its anticipated track the Tropical Low will approach the coast of Australia near the border between Queensland and the Northern Territory.  It will bring gusty winds and locally heavy rain.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Wasi Develops Near Samoa

Tropical Cyclone Wasi developed near Samoa on Friday night.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Wasi was located at latitude 13.6°S and longitude 172.9°W which put it about 20 miles (35 km) west of Falealupo, Samoa and about 185 miles (300 km) west-northwest of Pago Pago, American Samoa.  Wasi was moving toward the southeast at 11 m.p.h. (17 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 993 mb.

Tropical Cyclone Wasi spun up out of the same elongated trough of low pressure near Samoa that produced Tropical Cyclone Vicky on Thursday.  A small center of low pressure developed west-northwest of Samoa on Friday.  More thunderstorms formed near the center of circulation and the system was classified as Tropical Cyclone Wasi.  Microwave satellite imagery indicated that there was a tight inner core in the tropical cyclone.  Storms near the core were generating upper level divergence which was pumping mass away from Tropical Cyclone Wasi.  The circulation around Wasi was even smaller than the circulation around Tropical Cyclone Vicky.  Winds to tropical storm force only extended out about 50 miles (80 km) from the center of Tropical Cyclone Wasi.

Tropical Cyclone Wasi will move into an environment somewhat favorable for intensification during the next 24 to 36 hours.  Wasi will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the tropical cyclone.  Those winds will cause moderate vertical wind shear, but the winds may not be strong enough to prevent intensification.  Tropical Cyclone Wasi could strengthen during the next 24 to 36 hours.  Since the circulation around Wasi is so small, if the tropical cyclone moves into an area where the upper level winds are stronger, it could weaken quickly.

Tropical Cyclone Wasi will move around the western end of a high pressure system over the South Pacific Ocean.  The high will steer Wasi toward the southeast during the next 12 hours.  Wasi will move more toward the south later in the weekend.  On its anticipated track Tropical Cyclone Wasi will bring gust winds and locally heavy rain to portions of Samoa during the next 24 hours.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Vicky weakened as it passed near Niue on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Vicky was located at latitude 19.7°S and longitude 168.7°W which put oit about 95 miles (150 km) southeast of Niue.  Vicky was moving toward the south-southeast at 13 m.p.h. (20 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 1001 mb.

Tropical Cyclone Vicky Forms Near Samoa

Tropical Cyclone Vicky formed near Samoa on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Vicky was located at latitude 15.2°S and longitude 170.6°W which put it about 35 miles (55 km) south of Pago Pago, American Samoa.  Vicky was moving toward the southeast at 9 m.p.h. (15 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 992 mb.

A small low pressure system developed quickly within a large elongated trough extending east-southeast across Samoa on Thursday.  A small well defined circulation was evident on satellite imagery.  Thunderstorms developed near the center of the low pressure system and it was designated as Tropical Cyclone Vicky.  Storms near the center began to generate upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation.  A weather station at Pago Pago reported a sustained wind speed of 43 m.p.h. (69 km/h) and a wind gust of 75 m.p.h. (120 km/h) when the developing tropical cyclone passed nearby.

Tropical Cyclone Vicky will move through an environment only marginally favorable for intensification during the next several days.  Vicky will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western side of an upper level ridge over the South Pacific Ocean that extends southeast of Samoa.  The ridge will produce strong northwest winds which will cause moderate to strong vertical wind shear.  The wind shear will inhibit intensification and could cause Tropical Cyclone Vicky to weaken.  Since the circulation around Vicky is small, it could weaken rapidly if the wind shear increases.

Tropical Cyclone Vicky will move around the western side of a high pressure system over the South Pacific Ocean southeast of Samoa.  The ridge will steer Vicky toward the south during the next 24 to 48 hours.  On its anticipated track Tropical Cyclone Vicky could approach Niue in about 48 hours.  Vicky could be the equivalent of a tropical storm when it approaches Niue.

Tropical Cyclone Uesi Weakens East of Australia

Tropical Cyclone Uesi weakened east of Australia on Wednesday.  At 1:00 p.m. EST on Wednesday the center of Tropical Cyclone Uesi was located at latitude 25.9°S and longitude 161.7°E which put it about 500 miles (805 km) east-northeast of Brisbane, Australia.  Uesi was moving toward the south-southwest at 13 m.p.h. (20 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 977 mb.

Tropical Cyclone Uesi weakened steadily on Wednesday as it moved into a more unfavorable environment.  An upper level low over eastern Australia and an upper level ridge over the South Pacific Ocean interacted to produce strong northerly winds which blew across the top of Uesi.  Those winds caused strong vertical wind shear and they pushed the upper part of the circulation to the south of the lower level circulation.  Thunderstorms were only occurring in bands south of the center of Tropical Cyclone Uesi.  Bands in other parts of the tropical cyclone consisted primarily of showers and lower clouds.

Tropical Cyclone Uesi will continue to weaken as it moves into an even more unfavorable environment.  The upper low over eastern Australia and the upper ridge over the South Pacific will steer Uesi toward the south.  Tropical Cyclone Uesi will move over colder water.  The trough and the ridge will also continue to cause strong vertical wind shear.  The combined effects of colder water and strong wind shear will cause Tropical Cyclone Uesi to weaken during the next several days.

Tropical Cyclone Uesi Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Uesi strengthened to the equivalent of a hurricane/typhoon over the Coral Sea northwest of New Caledonia on Monday. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Uesi was located at latitude 18.4°S and longitude 162.5°E which put it about 125 miles (200 km) northwest of Poum, New Caledonia.  Uesi was moving toward the south at 6 m.p.h. (10 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 Uesi exhibited evidence of being the equivalent of a hurricane/typhoon on Monday.  Microwave satellite imagery showed indications of the development of an eye in the lower and middle levels of Uesi.  The tops of tall thunderstorms around the center of circulation obscured the developing eye on conventional visible and infrared satellite images.  A ring of strong thunderstorms around the center of Tropical Cyclone Uesi was producing the strongest wind speeds.  Bands of showers and thunderstorms were revolving around the core of Uesi.  The strongest rainbands were in the southern half of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center in the southern half of the circulation and out 100 miles (160 km) in the northern half.

Tropical Cyclone Uesi will move through an environment favorable for intensification during the next 24 to 36 hours.  Uesi will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western end of an upper level ridge over the South Pacific Ocean.  The ridge will produce northerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be great enough to prevent further intensification.  Tropical Cyclone Uesi will likely continue to strengthen during the next 24 to 36 hours.

Tropical Cyclone Uesi will move around the western end of a high pressure system over the South Pacific Ocean during the next several days.  The high pressure system will steer Uesi toward the south.  On its anticipated track the core of Tropical Cyclone Uesi will pass near and just to the west of northern New Caledonia during the next 24 to 36 hours.  Rainbands on the eastern side of Uesi could bring gusty winds and locally heavy rain to parts of New Caledonia.

Tropical Cyclone Uesi Develops Rapidly over Coral Sea

Tropical Cyclone Uesi developed rapidly over the Coral Sea on Sunday.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Uesi was located at latitude 16.6°S and longitude 163.6°E which put it about 230 miles (370 km) north of New Caledonia. Ueusi was moving toward the south at 7 m.p.h, (11 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.

The circulation around Tropical Cyclone Uesi organized quickly on Sunday.  The inner end of a band of showers and thunderstorms wrapped around the western side of the center of circulation.  More thunderstorms formed in other rainbands.  The strongest bands were in the eastern and southern parts of the circulation.  Storms near the center of circulation generated upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out 100 miles (160 km) from the center.

Tropical Cyclone Uesi will move through an environment favorable for intensification during the next 48 hours.  Uesi will move over water where the Sea Surface Temperature is near 30°C.  It will move under the western end of an upper level ridge over the South Pacific Ocean.  The ridge will produce northerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will mot be strong enough to prevent intensification.  Tropical Cyclone Uesi is likely to strengthen into the equivalent of a hurricane/typhoon during the next 12 to 24 hours.

Tropical Cyclone Uesi will move around the western end of a high pressure system over the South Pacific Ocean.  The high will steer Uesi toward the south during the next several days.  On its anticipated track the center of Tropical Cyclone Uesi could approach the northern end of New Caledonia in about 48 hours.  Uesi will likely be the equivalent of a hurricane/typhoon when it nears New Caledonia.

Tropical Cyclone Tino Speeds Across Tonga

Tropical Cyclone Tino sped quickly across Tonga on Saturday.  The core of Tino passed northeast of Nuku Alofa and the most populated island of Tonga.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Tino was located at latitude 24.0°S and longitude 170.6°E which put it about 370 miles (595 km) east-southeast of Nuku Alofa, Tonga.  Tino was moving toward the southeast at 26 m.p.h. (42 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 970 mb.

The strongest part of Tropical Cyclone Tino passed northeast of the more populated Tongatapu Group of islands in Tonga.  The core of Tino passed closer to the Vava’u Group and Ha’apai Group of islands in Tonga.  Winds to tropical storm force extended out 350 miles (565 km) from the center of Tino.  Tropical Cyclone Tino brought gusty winds and heavy rain to parts of Tonga.

Tropical Cyclone Tino began to weaken after it passed across Tonga.  Tino moved over water where the Sea Surface Temperature was cooler than 26°C.  Tropical Cyclone Tino moved southwest of an upper level ridge over the South Pacific Ocean.  The ridge caused moderate vertical wind shear and the wind shear contributed to the weakening of Tino.  Colder Sea Surface Temperatures and moderate vertical wind shear will cause Tropical Cyclone Tino to make a transition to an extratropical cyclone during the next two days.

Tropical Cyclone Tino Brings Wind, Rain to Eastern Fiji

Tropical Cyclone Tino brought wind and rain to eastern Fiji on Friday.  The core of Tino moved east of Vanua Levu but the large circulation around the tropical cyclone brought wind and rain across eastern Fiji.  There were reports of flash floods in some parts of Fiji.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Tino was located at latitude 18.6°S and longitude 176.7°W which put it about 190 miles (305 km) north-northwest of Nuku Alofa, Tonga.  Tino was moving toward the southeast at 27 m.p.h. (45 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 964 mb.

Tropical Cyclone Tino intensified into the equivalent of a hurricane/typhoon as it moved over eastern Fiji.  The inner end of a rainband wrapped around the center of circulation and a possible eye was seen on some infrared satellite images.  The strongest winds were occurring in a ring of thunderstorms around the center of circulation.  Bands of showers and thunderstorms were revolving around the core of the tropical cyclone.  There was a large circulation around Tropical Cyclone Tino.  Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 400 miles (645 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Tino was 11.5.  The Hurricane Size Index (HSI) was 22.6 and the Hurricane Wind Intensity Size Index (HWISI) was 34.1.  Tropical Cyclone Tino was capable of causing widespread mostly minor damage and smaller areas of more significant damage.

Tropical Cyclone Tino will move through an environment favorable for intensification during the next 12 hours.  Tino will move over water where the Sea Surface Temperature is near 28°C.  It will move around the southwestern portion 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, but the shear will not be strong enough during the next 12 hours to prevent intensification.   The wind speed will increase in about a day or so and more vertical wind shear will cause Tropical Cyclone Tino to weaken when that occurs.

Tropical Cyclone Tino will around the southwestern end of a high pressure system over the South Pacific Ocean.  The high will steer Tino toward the southeast.  On its anticipated track the center of Tropical Cyclone Tino could affect Tonga within 12 hours.  Tino will be the equivalent of a hurricane/typhoon when it moves over Tonga.  It will bring strong winds and rain.  Locally heavy rain could cause flash floods.

Tropical Cyclone Tino Forms North of Fiji

Tropical Cyclone Tino formed north of Fiji on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Tino was located at latitude 14.3°S and longitude 178.3°E which put it about 155 miles (250 km) west-northwest of Labasa, Fiji.  Tino was moving toward the southeast at 13 m.p.h. (15 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 985 mb.

The circulation around a large area of low pressure north of Fiji consolidated around a distinct low level center of circulation on Thursday and the Fiji Meteorological Service designated the system as Tropical Cyclone Tino.  The circulation around Tino was still organizing.  A primary band of showers and thunderstorms wrapped around the northern, eastern and southern sides of the circulation.  Other bands of showers and thunderstorms were forming around Tropical Cyclone Tino.  Winds to tropical storm force extended out 400 miles (645 km) north of the center of circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center in the southern half of the tropical cyclone.

Tropical Cyclone Tino will move through an environment favorable for intensification during the next 24 to 36 hours.  Tino will move over water where the Sea Surface Temperature is near 28°C.  It will move around the southwestern part of an upper level ridge.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will generate moderate vertical wind shear.  The wind shear will slow the rate of intensification, but the shear will not be strong enough to keep Tropical Cyclone Tino from getting stronger.  Tino could intensify into the equivalent of a hurricane/typhoon during the next 24 to 36 hours.

Tropical Cyclone Tino will move southwest of a high pressure system over the South Pacific Ocean.  The high will steer Tino toward the southeast during the next few days.  On its anticipated track the center of Tropical Cyclone Tino could be near the eastern end of Vanua Levu in about 12 hours.  Tino could approach Tonga in about 36 hours.  Tropical Cyclone Tino will bring gusty winds and locally heavy rain to Vanua Levu, Taveuni and many of the smaller islands in eastern Fiji.  Locally heavy rain  could cause flash floods in some locations.

Weakened Tropical Cyclone Sarai Moves Across Tonga

A weakened Tropical Cyclone Sarai moved across Tonga on Monday.  At 10:00 p.m. EST on Monday the center of Tropical Cyclone Sarai was located at latitude 20.6°S and longitude 174.9°W which put it about 30 miles (50 km) northeast of Nuku Alofa, Tonga.  Sarai was moving toward the northeast at 8 m.p.h. (13 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 989 mb.

Tropical Cyclone Sarai moved south of an upper level ridge on Monday.  The upper level ridge produced strong westerly winds which blew across the top of Sarai.  Those winds caused strong vertical wind shear and they blew the tops off of thunderstorms in Tropical Cyclone Sarai.  The circulation in the lower levels of Sarai remained intact, but it consisted of showers and lower clouds.  The wind speed gradually decreased during Monday.

The center of Tropical Cyclone Sarai passed just north of the Tongatapu Group of islands.  Sarai passed over the Ha’apai Group of islands.  Tropical Cyclone Sarai brought winds to tropical storm force and squally weather to parts of Tonga.  Rainfall amounts were relatively light because the wind sheared the tops off of any thunderstorms which started to form.

Tropical Cyclone Sarai will move through an environment unfavorable for intensification.  Sarai will move over water where the Sea Surface Temperature is near 27°C.  The upper level ridge will continue to cause strong vertical winds shear.  The wind shear will make it very difficult for new thunderstorms to form.  Tropical Cyclone Sarai is likely to weaken slowly as the circulation in the lower levels spins down.

Tropical Cyclone Sarai will move south of a subtropical high pressure system over the South Pacific Ocean.  The high will steer Sarai toward the east during the next several days.  On its anticipated track Tropical Cyclone Sarai will move south of the Vava’u Group of Islands during the next 24 hours.  Sarai could reach Niue in less than 30 hours.