Tag Archives: Port Vila

Tropical Cyclone Oma Spins Northwest of Vanuatu

Tropical Cyclone Oma continued to spin over the Coral Sea northwest of Vanuatu on Thursday.  At 7:00 p.m. EST on Thursday the center of Tropical Cyclone Oma was located at latitude 15.3°N and longitude 165.1°E which put it about 260 miles (420 km) northwest of Port Vila, Vanuatu.  Oma was nearly stationary.  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 Oma exhibited evidence of greater organization on Thursday.  The inner end of a rainband wrapped more tightly around the center of circulation.  Other bands of showers and thunderstorms also exhibited greater organization.   Storms around the center of circulation generated more upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out about 200 miles (320 km) from the center of circulation.

Once Tropical Cyclone Oma starts to move, it will move through an area favorable for intensification.  Oma will move over water where the Sea Surface Temperature is near 30°C.  It will move into a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Oma will be likely to intensify and it will likely strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Oma has been in an area where the winds at the steering level were weak and it has moved little during the past several days.  An upper level ridge east of Oma is forecast to strengthen during the next few days.  When the ridge strengthens, it will start to steer Tropical Cyclone Oma toward the southwest.  On its anticipated track Oma will move slowly away from Vanuatu and it could be north of New Caledonia in a few days.

Tropical Cyclone Oma Forms Northwest of Vanuatu

Tropical Cyclone Oma formed over the Coral Sea northwest of Vanuatu on Tuesday.  At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Oma was located at latitude 13.8°S and longitude 165.6°E which put it about 330 miles (535 km) northwest of Port Vila, Vanuatu.  Oma was moving toward the east at 7 m.p.h. (11 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 988 mb.

A distinct low level center of circulation formed within a broader area of low pressure northwest of Vanuatu on Tuesday and the Fiji Meteorological Service designated the system as Tropical Cyclone Oma.  The distribution of thunderstorms around Oma was asymmetrical.  Many of the stronger thunderstorms were occurring in bands northwest of the center of circulation.  Bands southeast of the center consisted primarily of showers and lower clouds.  The thunderstorms northwest of the center were generating upper level divergence which was pumping mass away to the northwest of the tropical cyclone.

An upper level ridge northeast of Vanuatu was producing southeasterly winds which were blowing toward the top of Tropical Cyclone Oma.  Those winds were causing moderate vertical wind shear and they were inhibiting upper level divergence to the southeast of Oma.  The wind shear was the probable cause of the asymmetrical distribution of thunderstorms.

Tropical Cyclone Oma will move through an environment somewhat favorable for intensification during the next several days.  The upper level ridge will continue to cause vertical wind shear.  However, Oma will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone Oma could slowly strengthen during the next day or two.

Tropical Cyclone Oma is currently embedded in a monsoon trough that is steering it toward the east.  A subtropical ridge is forecast to strengthen east of Vanuatu.  Oma will slow down while the ridge builds east of Vanuatu and it could linger northwest of Vanuatu for several days.  The ridge will eventually turn Tropical Cyclone Oma toward the south.  The timing and location of that turn will be important.  If Oma moves farther east before it turns southward, then it could approach northwest Vanuatu in 24 to 36 hours.  If Oma stalls and then turns southward, then the strongest part of the tropical cyclone could pass west of Vanuatu.  Tropical Cyclone Oma could eventually move near New Caledonia in a few days.

Tropical Cyclone Hola Develops Over Vanuatu

Tropical Cyclone Hola developed over Vanuatu on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Hola was located at latitude 16.2°S and longitude 168.1°E which put it near Ambrym and about 110 miles (180 km) north of Port Vila, Vanuatu.  Hola was moving toward the west-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 992 mb.

A large area of showers and thunderstorms northwest of Fiji moved slowly westward toward Vanuatu during the past few days.  The system was designated Tropical Cyclone Hola when a center of circulation developed in the area of storms on Tuesday.  Thunderstorms formed on all sides of the center, but there were more thunderstorms on the western side of the center.  Bands of showers and storms were beginning to revolve around the core of the circulation.  The storms near the center were starting to generate upper level divergence which was pumping mass away from the center of circulation.

Tropical Cyclone Hola will move through an environment favorable for intensification during the next two or three days.  Hola will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds over that area are weak and there is little vertical wind shear.  Tropical Cyclone Hola should intensify during the next 48 to 72 hours.  Rapid intensification could occur once the core of the circulation is fully organized.  Hola could strengthen into the equivalent of a hurricane/typhoon during the next 24 hours.  Hola could become the equivalent of a major hurricane within three days.

Tropical Cyclone Hola is moving near the northwestern end of a subtropical ridge which is steering Hola toward the west-southwest.  A slow motion toward the southwest is forecast during the next day or so while Hola rounds the northwestern end of the ridge.  Tropical Cyclone Hola will turn more toward the southeast after it rounds the subtropical ridge.  On its anticipated track the center of Tropical Cyclone Hola will move near Ambrym, Malekula, Paama, Lopevi, and Epi.  Hola is forecast to pass west of Port Vila, but it could be near New Caledonia and the Iles Loyaute in two or three days.

Tropical Cyclone Hola will strengthen as it moves slowly toward the southwest during the next 24 hours.  The stronger tropical cyclone will produce gusty winds and it will drop heavy rain over the central parts of Vanuatu.  Heavy rain will fall over Espiritu Santo, Maewo, Ambae, Pentecost, Malo, Ambrym, Paama, Lopevi, Tongoa, Epi, Emae, the Shepherd Islands, Nguna, Emao, and Efate.  Locally heavy rain could create the potential for floods in some of those locations.