Tag Archives: Vanuatu

Stronger Tropical Cyclone Cook Nears New Caledonia

Tropical Cyclone Cook strengthened on Sunday as it neared New Caledonia.  At 8:00 p.m. EDT on Sunday the center of Tropical Cyclone Cook was located at latitude 20.3°S and longitude 165.8°E which put it about 150 miles (240 km) north-northwest of Noumea, New Caledonia.  Cook was moving toward the south-southwest at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 969 mb.

Tropical Cyclone Cook intensified on Sunday as the organization of the core improved.  A circular eye developed inside a ring of strong thunderstorms.  The fastest winds were occurring in the ring of storms around the eye.  A number of other bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Cook.  Thunderstorms close to the center of circulation were generating upper level divergence which was pumping out mass to the southeast of the tropical cyclone.  Winds to tropical storm force extended out about 180 miles (290 km) from the center of circulation.

Tropical Cyclone Cook moved through an environment favorable for tropical cyclones on Sunday.  It moved over water where the Sea Surface Temperature was near 29°C.  An upper level ridge east of Cook produced northerly winds which were blowing toward the tropical cyclone, but the wind shear was not great enough to inhibit intensification.  Tropical Cyclone Cook should maintain its intensity until it makes landfall in New Caledonia.  Cook will begin to weaken after the center begins to interact with land.

A subtropical ridge east of Cook is steering the tropical cyclone toward the south-southwest.  A southerly motion is expected to bring the center of Tropical Cyclone Cook to New Caledonia on Monday.  The center of Tropical Cyclone Cook is likely to make landfall between Houailou and Thio on the central coast of New Caledonia.

The Hurricane Intensity Index (HII) for Tropical Cyclone Cook is 16.5.  The Hurricane Size Index (HSI) is 16.8 and the Hurricane Wind Intensity Size Index (HWISI) is 33.3.  The indices indicates that Tropical Cyclone Cook is capable of causing serious regional wind damage.  Tropical Cyclone Cook will also produce heavy rain and a chance for flash floods.

Strengthening Tropical Cyclone Cook Brings Wind and Rain to Vanuatu

Strengthening Tropical Cyclone Cook brought wind and rain to Vanuatu on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Cook was located at latitude 17.8°S and longitude 167.4°E which put it about 65 miles (105 km) west of Port Vila, Vanuatu.  Cook was moving toward the south at 5 m.p.h. (8 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 985 mb.

Tropical Cyclone Cook strengthened quickly on Saturday as it moved through central portions of Vanuatu.  A primary rainband wrapped around the center of circulation and a clear area appeared intermittently on satellite imagery.  The strongest winds were occurring in a ring of thunderstorms around the forming eye.  The thunderstorms near the center were generating upper level divergence which was pumping out mass toward the southeast of Tropical Cyclone Cook.  Additional bands of showers and thunderstorms were forming in the eastern half of the circulation.  Winds to tropical storm force extend out about 150 miles (240 km) from the center of circulation.

Tropical Cyclone Cook will move through an environment that will be favorable for intensification during the next 24 to 36 hours.  Cook will move over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge to the east of Cook is generating northerly winds which are blowing toward the tropical cyclone, but the vertical wind shear is minimal.  Warm SSTs and little vertical wind shear will allow Tropical Cyclone Cook to intensify.  A period of rapid intensification could occur after the eye and eyewall are completely formed.  Tropical Cyclone Cook should become the equivalent of a hurricane/typhoon on Sunday.

Tropical Cyclone Cook is moving around the western end of a subtropical ridge.  The ridge is steering Cook a little to the west of due south.  A general south-southwesterly motion is expected to continue for another 24 to 36 hours.  On its anticipated track Tropical Cyclone Cook will move away from Vanuatu and toward New Caledonia.  Tropical Cyclone Cook could approach New Caledonia in about 36 hours.

The core of Tropical Cyclone Cook will continue to bring wind and rain to the area around Port Vila, Vanuatu on Sunday.  Storms in the outer rainbands will bring wind and rain to the southern parts of Vanuatu.  Tropical Cyclone Cook will be the equivalent of a hurricane/typhoon when it nears New Caledonia.  Cook will be capable of causing wind damage and heavy rain could cause flash flooding.

Tropical Cyclone Zena Forms Near Vanuatu and Moves Toward Fiji

Tropical Cyclone Zena formed near Vanuatu on Tuesday.  After several weaker circulations developed within a large trough of low pressure that extended from Tonga west-northwest to near Vanuatu during the past few days, a stronger center of circulation organized near Espiritu Santo on Tuesday.  Thunderstorms consolidated around the center of circulation and the system was designated at Tropical Cyclone Zena (18P).

At 10:00 p.m. EDT on Tuesday the center of Tropical Cyclone Zena was located at latitude 17.6°S and longitude 173.1°E which put it about 300 miles (480 km) west of Nadi, Fiji.  Zena was moving toward the east-southeast at 27 m.p.h. (44 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 978 mb.

Tropical Cyclone Zena is a small system.  Tropical storm force winds only extend out about 100 miles (160 km) from the center of circulation.  The Hurricane Size Index (HSI) for Zena is only 6.4  A primary rainband wrapped around the center of circulation and a tiny pinhole eye has appeared intermittently on satellite imagery.  There is a circular ring of thunderstorms at the core of Zena.  The outer portion of the circulation is asymmetrical.  Most of the bands of thunderstorms are east of the center of circulation.

The environment around Tropical Cyclone Zena is somewhat favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C to 30°C.  An upper level ridge is generating moderate west-northwesterly winds around the tropical cyclone.  Much stronger upper level winds are south of Tropical Cyclone Zena.  The upper level winds are inhibiting outflow to the west of the center of the circulation, but they did not inhibit intensification on Tuesday.  Rapid motion of Tropical Cyclone Zena toward the east-southeast appears to have offset some of the effects of the vertical wind shear.  Zena could continue to intensify in the short term, but its small size could make it very vulnerable to the effects of vertical wind shear, if the speed of the upper winds increase.

An upper level ridge located northeast of Zena is steering the tropical cyclone rapidly toward the east-southeast.  That general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Zena will be nearing Fiji in about 12 hours and it could be near Tonga in about 36 hours.  The center of Zena and the strongest winds could pass south of Viti Levu on Wednesday.

Tropical Cyclone Zena could bring strong winds to any of the southern islands of Fiji including southern Viti Levu, Beqa, Kadavu, Lau and the Lomaiviti group.  It could also cause heavy rain and floods.  Tropical Cyclone Zena could bring wind and rain to Tonga on Thursday.

Tropical Cyclone Winston Stalls Between Vanuatu and Fiji

Steering currents weakened on Sunday and Tropical Cyclone Winston stalled about half way between Vanuatu and Fiji.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Winston was located at latitude 18.0°S and longitude 172.5°E which put it about 300 miles (480 km) east of Port Vila, Vanuatu.  Winston was moving toward the west-southwest at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 135 m.p.h. (215 km/h).  The minimum surface pressure was 952 mb.

Vertical wind shear over Winston decreased on Sunday and the organization of the tropical cyclone improved.  The eye has become more visible on satellite images and thunderstorms surrounding the eye are generating more upper level divergence.  Easterly winds which were blowing over the top of Winston diminished and the upper level divergence is again flowing out in all directions.

Tropical Cyclone Winston is in an environment that favors intensification.  It is over water where the Sea Surface Temperature is near 30°C.  There is not much vertical wind shear and Winston is likely to intensify during the next 24 hours.

Winston has moved into an area that is between two subtropical ridges.  As a result, it is in an area where the steering winds are not very strong.  The forward motion of Winston has slowed and there is some indication that it may be turning southward.  The guidance from numerical models is forecasting a southerly or southeasterly motion during the next 24 to 48 hours.  On its anticipated track Tropical Cyclone Winston is predicted to stay east of Vanuatu.  However, a more westerly track could bring it closer to that country.

Tropical Cyclone Winston Hits Viti Levu Then Moves West of Fiji

The eye of destructive Tropical Cyclone Winston moved over the northern part of Viti Levu and then continued west of Fiji.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Winston was located at latitude 17.5°S and longitude 174.4°E which put it about 425 miles (685 km) east of Port Vila, Vanuatu.  Winston was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 937 mb.  Winston was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.

The core of intense Tropical Cyclone Winston was disrupted as it moved across the northern portion of Viti Levu.  However, the core reorganized once it moved back over water.  It has a well formed eye surrounded by a circular eyewall.  Several rainbands are spiraling around the core.  Thunderstorms in the core of Tropical Cyclone Winston are generating upper level divergence.

The environment surrounding Tropical Cyclone Winston is a little less favorable for intensification.  Winston is still moving over water where the Sea Surface Temperature is near 30°C.  However, an upper level ridge located to the southeast of Winston is generating easterly winds that are inhibiting upper level divergence to the east of the tropical cyclone.  There is still strong upper level divergence in the western half of the circulation.  The vertical wind shear has caused Winston to weaken slowly, but the shear has not been strong enough to disrupt the reorganization of the circulation.  Tropical Cyclone Winston could maintain its intensity or even strengthen somewhat during the next day or two.

The subtropical ridge southeast of Winston is steering the tropical cyclone toward the west and that general motion is expected to continue for at least another 24 hours.  Guidance from numerical models suggest that Winston will turn toward the south early next week.  However, the guidance from the models has consistently forecast a turn to the south that has not yet occurred.  The guidance predicts that Tropical Cyclone Winston will turn south before it can affect Vanuatu, but people in that country should monitor the progress of Winston closely.

Radar and satellite information indicate that the northern eyewall of Tropical Cyclone Winston may have moved over the southern part of Vanua Levu.  The eye moved across the northern part of Viti Levu.  Press reports indicated Winston produced significant wind damage and power outages in parts of Fiji.

Destructive Tropical Cyclone Winston Hits Fiji

Destructive Tropical Cyclone Winston hit parts of Fiji on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Winston was located at latitude 17.1°N and longitude 179.6°E which put it about 125 miles (205 km) east-northeast of Suva, Fiji.  The eye was just south of Vanua Levi.  Winston was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 185 m.p.h. (295 km/h) which made Winston the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  There were wind gusts to 225 m.p.h. (360 km/h) and the minimum surface pressure was 903 mb.

Winston is a compact symmetrical tropical cyclone.  It has a very well formed eye with a ring of very strong thunderstorms surrounding the eye.  Several spiral bands curl into the eyewall.  Thunderstorms around the eye are generating strong upper level divergence which pumped out mass and allowed the pressure to decrease rapidly during the past few hours.

Tropical Cyclone Winston is in a nearly perfect environment for a tropical cyclone.  It is over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is almost no vertical wind shear.  Winston could continue to intensify for another 6 to 12 hours.  It is hard for a tropical cyclone to remain as strong as Winston is for an extended period of time.  An eyewall replacement cycle, or movement over one of the large islands of Fiji could disrupt the circulation and cause Winston to weaken.

A subtropical ridge south of Winston is steering the tropical cyclone to the west and that general motion is expected to continue for the next day or two.  On its anticipated track the center of Tropical Cyclone Winston could pass very near the south coast of Vanua Levu and the north coast of Viti Levu.

Winston is an extremely dangerous tropical cyclone.  The Hurricane Intensity Index for Tropical Cyclone Winston is 44.1.  The Hurricane Size Index is 12.9 and the Hurricane Wind Intensity Size Index is 57.0.  These indices mean the Tropical Cyclone Winston is capable of producing regional catastrophic damage.  In addition to wind damage heavy rain will cause inland flooding and storm surges will inundate low lying portions of the coast.  The eye of Winston passed over Vanua Balavu and Yacata earlier on Friday and it is currently just south of Vanua Levi.

Tropical Cyclones Winston and Tatiana Form over SW Pacific

A pair of tropical cyclones named Winston and Tatiana formed over the southwestern Pacific Ocean on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Winston was located at latitude 18.4°S and longitude 171.6°E which put it about 445 miles (720 km) west of Suva, Fiji.  Winston was moving toward the south at 7 m.p.h. (11 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 974 mb.

At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Tatiana was located at latitude 17.3°S and longitude 159.0°E which put it about 620 miles (1000 km) northwest of Noumea, New Caledonia.  Tatiana was moving toward the east-southeast at 6 m.p.h. (10 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 Winston is the stronger and more well organized storm.  It has a well developed eye surrounded by a ring of strong thunderstorms.  Winston is in a very favorable environment.  It is moving over water where the Sea Surface Temperatures are near 31°C.  There is an upper level ridge over Winston and so the upper level winds are light and divergence is occurring in all directions.  Winston is likely to continue to intensify rapidly on Friday and it could become the equivalent of a major hurricane.

Tropical Cyclone Tatiana is smaller and not as well organized.  Tatiana is moving over water where the Sea Surface Temperatures are near 30°C.  However the western end of the same upper level ridge that is over Winston is generating brisk northerly winds over the top of Tropical Cyclone Tatiana.  As a result, vertical wind shear is inhibiting upper level divergence to the north of the center of Tatiana and it is also tilting the circulation toward the south with height.  Wind shear is likely to prevent Tatiana from intensifying significantly.

A subtropical ridge is steering both Winston and Tatiana toward the south.  Tropical Cyclone Winston will pass west of Fiji, but it could come close enough to the extreme southeastern islands of Vanuatu to bring wind and rain to some of those islands.  Tropical Cyclone Tatiana is likely to pass west of New Caledonia, but it could bring rain and higher surf to the west coast of that island.

Tropical Cyclone Ula Equivalent of Cat. 4 Hurricane

Tropical Cyclone continued to intensify steadily on Saturday and it is now the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 8:00 p.m. EDT on Saturday the center of Tropical Cyclone Ula was located at latitude 19.8°S and longitude 171.4°E which put it about 400 miles (640 km) east-northeast of Noumea, New Caledonia.  Ula was moving toward the southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (270 km/h).  The minimum surface pressure was 933 mb.

Tropical Cyclone Ula has circular eye with a diameter of 24 miles (38 km).  The eye is surrounded by a closed ring of thunderstorms.  Other spiral bands are rotating around the center of circulation.

Tropical Cyclone Ula is moving through an environment that is almost perfect for intensification.  The upper level winds are very light and there is almost no vertical wind shear.  Ula is over water where the Sea Surface Temperature (SST) is near 28°C.  It intensified quickly on Saturday and it has the potential to intensify a little more before it moves over cooler SSTs.

Tropical Cyclone Ula is moving around the western end of a subtropical ridge which is steering it toward the southwest.  That general motion is expected to continue for another 12 to 24 hours.  As Ula reaches the western end of the ridge it will start moving more toward the south.  Eventually the mid-latitude westerlies will start to steer Ula toward the southeast.

On its anticipated track Tropical Cyclone Ula could pass near the extreme southeastern islands of Vanuatu.  The greatest risk is to Aneityum and Futuna.  Ula could also bring wind and rain to Tanna, Aniwa, and Erromango.  The core with the strongest winds should pass southeast of Vanuatu, but Ula could bring wind and rain to some of those islands.  The center of Ula is expected to pass east of New Caledonia early next week, but it could also bring wind and rain to the Iles Loyaute.

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.