Tag Archives: Samoa

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.