Category Archives: South Pacific

Tropical Cyclone Ula Intensifies Rapidly, Threatens Vanuatu

Tropical Cyclone Ula intensified rapidly on Friday as it started to move toward Vanuatu.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Ula was located at latitude 18.7°S and longitude 173.5°E which put it about 545 miles (880 km) east-northeast of Noumea, New Caledonia.  Ula was moving toward the southwest at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 95 m.p.h, (155 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 963 mb.

Tropical Cyclone Ula intensified rapidly on Friday because it was in a very favorable environment.  Satellite images showed that there is a 15 mile (24 km) wide eye at the center of Ula.  Additional spiral bands are rotating outside the core of the tropical cyclone.  Ula has a very symmetrical structure.  Thunderstorms in the core of Ula are creating upper level divergence, especially to the west of the center of circulation.

Tropical Cyclone Ula is in an environment favorable for further intensification.  It is over water where the Sea Surface Temperature is near 28°C.  An upper level ridge to the east of Ula is producing northeasterly winds over the top of the tropical cyclone.  However, the vertical wind shear is only modest and further intensification is possible.  Tropical Cyclone Ula could become the equivalent of a major hurricane during the weekend.

A subtropical ridge east of Ula is starting to steer the tropical cyclone toward the southwest.  That general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Ula could approach the southern islands of Vanuatu in about 48 hours.  It could be a very strong tropical cyclone when it nears those islands.

Tropical Cyclone Ula Intensifies, Could Threaten Vanuatu

Tropical Cyclone Ula moved into a more favorable environment and it intensified on Thursday.  At 4:00 p.m. EDT on Thursday the center of Tropical Cyclone Ula was located at latitude 18.7°S and longitude 174.4°E which put it about 260 miles (420 km) west of Suva, Fiji.  Ula was moving toward the northwest at 3 m.p.h. (5 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 Ula has been moving slowly equatorward this week and it is now over slightly warmer Sea Surface Temperatures (SSTs).  Ula has extracted additional energy from the warmer water and the strength of thunderstorms near the core of the tropical cyclone increased.  The structure of the circulation is more symmetrical and an eyewall may be forming around the center of Ula.  The thunderstorms are also generating more upper level divergence, especially to the west of the center of the tropical cyclone.

Tropical Cyclone Ula is once again in a region that is favorable for intensification.  It is back over water where the SSTs are near 28°C.  An upper level ridge east of Ula is generating northeasterly winds over the top of the tropical cyclone, but the vertical wind shear is modest.  Tropical cyclone is likely to intensify further during the next 24 hours and it could become the equivalent of a hurricane on Friday.

Ula has been moving slowly northwest around the western end of a subtropical ridge.  The ridge is forecast to slowly strengthen during the next few days.  As the ridge strengthens it will start to steer Ula more toward the west.  On its anticipated track Tropical Cyclone Ula could move toward Vanuatu.

Tropical Cyclone Ula Bringing Strong Wind to SE Fiji

Tropical Cyclone Ula is bringing strong winds, heavy rain and high surf to the extreme southeastern islands of Fiji.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Ula was located at latitude 19.4°S and longitude 178.0°W which put it about 265 miles ( 430 km) east-southeast of Suva, Fiji.  Ula was moving toward the southwest at 9 m.p.h. (15 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. (205 km/h).  The minimum surface pressure was 961 mb.  Tropical Cyclone Ula was the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale.

The inner core structure of Tropical Cyclone Ula changed on Saturday and it may have gone through an eyewall replacement cycle.  Ula started the day with a small pinhole eye, but recent visible satellite imagery indicates that it has a larger, symmetrical eye.  Even though the inner core structure has changed, Tropical Cyclone Ula maintained its intensity.  The structure of Ula is still symmetrical, but most of the stronger thunderstorms are south and west of the center of circulation.

Tropical Cyclone Ula remains in an environment that is favorable for intensification.  It is over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds are light and there is not much vertical wind shear.  The favorable environment could allow Ula to maintain its intensity for another 12 to 24 hours.  After that time the tropical cyclone will move into an area where the SSTs are cooler and the upper level winds are stronger.  Cooler water and more vertical wind shear will cause Tropical Cyclone Ula to weaken.

A subtropical ridge is steering Tropical Cyclone Ula toward the southwest.  Ula is nearing the western end of the ridge and it is likely to turn more toward the south in a day or two.  The center of Tropical Cyclone Ula is near Vatoa, Ogea Levu and Ogea Driki.  It is bringing strong winds, heavy rain and large waves to those islands.  It will move near Ono-i-lau, Tuvana-i-colo and Tuvana-i-ro during the next few hours and conditions will get worse on those islands.

Tropical Cyclone Ula Bringing Wind and Rain to Northern Tonga

Tropical Cyclone Ula is bringing wind and rain to islands in northern Tonga.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Ula was located at latitude 18.3°N and longitude 175.6°W which put it about 100 miles (160 km) north-northwest of Tongatapu, Tonga.  Ula was moving toward the west-southwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 115 m.p.h. (150 km/h) and there were wind gusts to 135 m.p.h. (215 km/h).  The minimum surface pressure was 959 mb.

Lupepau’u airport on Vava’u reported maximum sustained winds of 65 m.p.h. (105 km/h) and wind gusts to 100 m.p.h. (160 km/h) when the center Tropical Cyclone Ula passed north of it.  Ula also brought strong winds and heavy rain to Tafahi, Fonaulei and Toku in northern Tonga.

Tropical Cyclone Ula intensified quickly during the past few hours and a pinhole eye is visible on conventional satellite images.  The eye is surrounded by a tight ring of strong thunderstorms.  Several spiral bands are rotating around the center of Ula.  One of the primary rainbands may be wrapping around the pinhole eye and concentric eyewalls may be developing.  Thunderstorms in the core of Tropical Cyclone Ula are generating upper level divergence that is pumping out mass in all directions.

Tropical Cyclone Ula is in an environment favorable for intensification.  Ula is moving over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds are relatively light and there is not much vertical wind shear.  Ula could intensify further during the next few hours, although an eyewall replacement cycle could cause fluctuations in intensity.  Tropical Cyclone Ula could move into an area where the upper level winds are stronger in 24 to 48 hours.  Ula will also move over cooler SSTs in several days.  The combination of more wind shear and cooler SSTs will weaken the tropical cyclone.

A subtropical ridge is steering Tropical Cyclone Ula toward the west-southwest and that general motion is expected to continue for another day or so.  After that time Ula will reach the western end of the ridge and turn more toward the south.  On its expected track Tropical Cyclone Ula could be approaching the southeastern islands of Fiji in about 24 hours.

Tropical Cyclone Ula Becomes Equivalent of Cat. 2 Hurricane South of Samoa

Tropical Cyclone Ula intensified quickly Wednesday into the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Ula was located at latitude 16.3°N and longitude 170.4°W which put it about 135 miles (220 km/h) south-southeast of Pago Pago, Samoa.  Ula was moving toward the southwest 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. (205 km/h).  The minimum surface pressure was 961 mb.

Tropical Cyclone Ula has a small, well organized inner core.  An eye has appeared intermittently on satellite imagery.  Thunderstorms near the core are generating upper level divergence which is pumping out mass and allowing the surface pressure to decrease.

Tropical Cyclone Ula is moving through an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 28.5°C.  The upper level winds are not very strong and there is not much vertical wind shear.  Ula could intensify a little more during the next 24 hours.

A subtropical ridge is steering Tropical Cyclone Ula toward the southwest and a general west-southwesterly motion is expected to continue during the next several days.  Ula is centered between Samoa, Niue and Tonga.  On its anticipated track Tropical Cyclone Ula will approach Tonga in about 24 hours.  It could be approaching Fiji in about three days.  Tropical Cyclone Ula is capable of bringing strong winds, high surf and heavy rain to the islands in its path.

Tropical Cyclone Ula Forms East of Samoa

A well-defined center of circulation consolidated within a very large area of thunderstorms straddling the Equator near the International Date Line and the system was classified as Tropical Cyclone Ula (06P).  At 5:00 a.m. EST on Wednesday the center of Tropical Cyclone Ula was located at latitude 12.5°S and longitude 166.6°W which put it about 325 miles (525 km) east-northeast of Pago Pago, Samoa.  Ula was moving toward the south-southeast at 15 m.p.h. (24 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.

Thunderstorms in a spiral rainband are wrapping around the center of circulation and microwave satellite imagery has suggested that an eye may be forming in Tropical Cyclone Ula.  Additional spiral bands are developing in the outer portion of the circulation.  The thunderstorms near the center of circulation are generating upper level divergence which is pumping out mass, especially to the east of the center of Ula.

Tropical Cyclone Ula is in an environment that is favorable for intensification.  It is over water where the Sea Surface Temperatures are between 28°C and 29°C.  The upper level winds are light and there is not much vertical wind shear.  Ula is likely to continue to intensify as the core of the circulation consolidates and it could become the equivalent of a hurricane within 24 to 36 hours.

Ula is currently being steered to the south-southeast by a subtropical ridge which is located east of the tropical cyclone.  The ridge is expected to intensify and extend westward.  If it does so, then the building ridge will cause Tropical Cyclone Ula to turn toward the southwest.  On its anticipated track the center of Tropical Cyclone could pass south of Samoa in 24 to 48 hours and it could approach Fiji in four or five days.

Tropical Cyclone Ula could bring strong winds and heavy rain to any island it passes near.

Tropical Cyclone Raquel Reorganizing Near Solomon Islands

Strong upper level winds blew away the upper potion of Tropical Cyclone Raquel on Wednesday.  However, the upper level winds lessened on Thursday and thunderstorms began to reform on the western side of the circulation.  At 5:00 p.m. EDT on Thursday the center of Tropical Cyclone Raquel was located at latitude 6.4°S and longitude 160.5°E which put it about 220 miles (360 km) north of Honiara in the Solomon Islands.  Raquel was moving toward the south-southeast at 3 m.p.h. (5 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 994 mb.

Tropical Cyclone Raquel is over water where the Sea Surface Temperatures are very warm.  However, an upper level ridge east of Raquel generated strong winds over the top of the tropical cyclone on Wednesday and blew away the upper parts of the circulation.  The upper level winds weakened on Thursday and new thunderstorms began to develop west of the center of circulation.  Upper level divergence is also occurring in the western half of the circulation and Raquel looks like a tropical cyclone again.  The upper level winds are still strong enough to inhibit intensification, but Raquel could strengthen further in the short term.

When the top parts of the circulation were blown away on Wednesday, the lower level circulation was steered by winds in the lower troposphere and it moved toward the northeast.  As the thunderstorms redevelop, the height of the circulation is increasing and Raquel is more likely to be steered by winds in the middle troposphere.  Those winds are expected to steer Raquel back toward the southwest.  On its anticipated track Raquel could again approach Santa Isabel Island on Friday.  It could bring winds and locally heavy rain to portions of the Central Solomon Islands.

Tropical Cyclone Raquel Forms Near the Solomon Islands

A distinct low level center of circulation was detected inside a large area of thunderstorms north of the Solomon Islands and the system was designated as Tropical Cyclone Raquel (25P).  At 11:00 p.m. EDT on Tuesday the center of Tropical Cyclone Raquel was located at latitude 6.5°S and longitude 158.9°E which put it about 210 miles (335 km) north of Honiara in the Solomon Islands.  Raquel was moving toward the southwest at 11 m.p.h. (18 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 989 mb.

Raquel is over water where the Sea Surface Temperature is quite warm and there is plenty of energy in the upper ocean to support intensification.  However, and upper level ridge east of Raquel is northeasterly winds over the top of the circulation and it is creating moderate amounts of vertical wind shear.  The wind shear is causing many of the stronger thunderstorms to occur on the western side of the circulation.  The wind shear may be tilting the vertical structure of the circulation toward the southwest and it is limiting the potential for intensification.

As Raquel moves around the western end of the upper level ridge, it is expected to be steered toward the south on Wednesday.  On its anticipated track Raquel is expected to move across Santa Isabel on Wednesday.  It could be near Guadacanal in 36 to 48 hours.  Raquel is likely to bring some wind and locally heavy rain to parts of the central Solomon Islands during the next two days.

Tropical Cyclone Solo (23P) Intensifying Slowly Over the Coral Sea

Tropical Cyclone Solo (23P) intensified slowly over the Coral Sea on Friday.  At 6:00 p.m. EDT on Friday the center of Tropical Cyclone Solo was located at latitude 17.1°S and longitude 161.1°E which put it about 470 miles northwest of Noumea, New Caledonia and about 470 miles west of Port Vila, Vanuatu.  Solo was moving toward the south-southeast at 13 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were gusts to 80 m.p.h.  The minimum surface pressure was 983 mb.

Solo is moving over warm Sea Surface Temperatures, but an upper level high to the east of it is producing northerly winds over the top of the circulation.  The vertical wind shear is causing more of the stronger thunderstorms to be located south of the center and it is inhibiting the intensification of Solo.  As a result it is intensifying slowly and that trend is expected to continue for the next day or two.  Eventually, when Solo moves to a higher latitude, stronger upper level winds will create more vertical wind shear and weaken it.

Solo is moving around the western end of a subtropical ridge.  As it gets farther south, Solo is expected to move more toward the southeast.  On its projected track, Solo would approach New Caledonia in about 36 hours.  It could be near hurricane intensity at that time.  Solo could bring strong winds and heavy rainfall to New Caledonia when it moves past.

Tropical Cyclone 23P Organizes Rapidly Over the Coral Sea

A well organized circulation developed rapidly within an area of thunderstorms over the Coral Sea and the system was designated Tropical Cyclone 23P.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone 23P was located at latitude 14.4°S and longitude 160.5°E which put it about 670 miles northwest of Noumea, New Caledonia and about 600 miles west-northwest of Port Vila, Vanuatu.  It was moving toward the southwest at 12 m.p.h.  The maximum sustained wind speed was 50 m.p.h. and there were gusts to 65 m.p.h.  The minimum surface pressure was 989 mb.

Tropical Cyclone 23P is located in an area where the upper level winds are light.  That allowed thunderstorms to develop and wrap around the core of the circulation.  Upper level divergence is pumping out mass in all directions and the pressure is decreasing.  The tropical cyclone is over Sea Surface Temperatures which are near 30°C, which means there is plenty of energy in the upper ocean to support further intensification.  Tropical Cyclone 23P could reach hurricane intensity in a day or two.

The tropical cyclone is moving around the western end of a subtropical ridge, which is steering it toward the southwest.  As it moves around the end of the ridge, it will turn more toward the southeast.  On its expected track Tropical Cyclone 23P could approach New Caledonia in 48 to 72 hours.