Tag Archives: New Caledonia

Tropical Cyclone Donna Moves Toward Vanuatu and Strengthens

Tropical Cyclone Donna moved toward Vanuatu and strengthened into the equivalent of a hurricane/typhoon on Wednesday.  At 8:00 p.m. EDT on Wednesday the center of Tropical Cyclone Donna was located at latitude 12.4°S and longitude 168.2°E which put it about 270 miles (435 km) north-northeast of Port Vila, Vanuatu.  Donna was moving toward the west at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 976 mb.

The circulation of Tropical Cyclone Donna organized further on Wednesday.  An eyelike feature appeared on some microwave satellite images.  An eyewall wrapped about two thirds of the way around the western side of the center of circulation.  A primary rainband curled around the southern and western portions of the core of Tropical Cyclone Donna.  Additional bands of showers and thunderstorms formed and revolved around the core of Donna.  Thunderstorms around the core generated strong upper level divergence which pumped out mass and allowed the pressure to decrease quickly.  A stronger pressure gradient force accelerated the air and resulted in faster wind speeds.

Tropical Cyclone Donna will continue to move through a favorable environment during the next several days.  Donna will move over water where the Sea Surface Temperature is near 30°C.  It is currently in an area where the upper level winds are weak and there is little vertical wind shear.  The combination of warm water and little shear will produce further strengthening and Tropical Cyclone Donna could continue to intensify rapidly.  Donna could intensify into the equivalent of a major hurricane within 24 to 48 hours.

Donna is moving around the northern side of a subtropical ridge which is steering the tropical cyclone toward the west.  A general westerly motion is expected to continue for another 24 hours.  After that time Tropical Cyclone Donna will approach the western end of the ridge and it will turn more toward the south.  Guidance from numerical models differs on the timing and location of the turn toward the south.  On its anticipated track the center of Tropical Cyclone Donna could approach some of the islands of northern Vanuatu in about 24 hours.  It could be a significant tropical cyclone at that time.

Tropical Cyclone 18P Develops Northeast of Vanuatu

Tropical Cyclone 18P developed quickly northeast of Vanuatu on Tuesday.  At 8:00 p.m. EDT on Tuesday the center of Tropical Cyclone 18P was located at latitude 12.7°S and longitude 171.7°E which put it about 695 miles (1120 km) north-northeast of Port Vila, Vanuatu.  The tropical cyclone was moving toward the east at 4 m.p.h. (6 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 992 mb.

The circulation of Tropical Cyclone 18P organized quickly on Tuesday.  More thunderstorms formed near the center of circulation and a  primary rainband wrapped around the eastern side of the center.  Additional bands of showers and thunderstorms developed in the outer regions of the circulation.  Thunderstorms near the core of the circulation generated upper level divergence which pumped out mass and allowed the surface pressure to decrease.

Tropical Cyclone 18P will be moving through an environment that will be very favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone 18P is centered underneath an upper level ridge and the upper level winds are light.  There is little vertical wind shear.  Tropical Cyclone 18P is likely to intensify rapidly and it could become the equivalent of a hurricane/typhoon within 24 hours.  Once an eye and eyewall form, Tropical Cyclone 18P could intensify very rapidly and it could become the equivalent of a major hurricane within 48 to 72 hours.

Tropical Cyclone 18P is moving through an area where the winds are the steering level are weak.  It has been moving slowly toward the east.  A subtropical ridge to the south of Tropical Cyclone 18P is expected to strengthen and it will turn the tropical cyclone toward the west for about 48 to 72 hours.  When Tropical Cyclone 18P nears the western end of the ridge, it will turn toward the south.  On its anticipated track, Tropical Cyclone 18P could approach Vanuatu in about three days and it could be a significant tropical cyclone at that time.

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 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.

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 Cyclone Winston Turns Back Toward Fiji

Tropical Cyclone Winston turned northeastward on Sunday and it began to move back toward Fiji.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Winston was located at latitude 22.6°S and longitude 179.9°E which put it about 345 miles (560 km) south-southeast of Suva, Fiji.  Winston was moving toward the northeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 70 m.p.h. (115 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 978 mb.

A subtropical ridge located northwest of Winston generated southwesterly winds over the top of the tropical cyclone.  The southwesterly winds produced moderate vertical wind shear, which caused Winston to weaken on Sunday.  The circulation of Tropical Cyclone Winston remains fairly intact.  A narrow band of thunderstorms is wrapped around the center of circulation and a remnant eyewall persists.  Other bands of thunderstorms are rotating around the eastern side of the cyclone.  Upper level divergence is still pumping mass out from the northeastern side of the circulation.

Tropical Cyclone Winston is currently over water where the Sea Surface Temperature is near 28°C.  As Winston moves northward it will move over warmer water.  It will also move into an area where the upper level winds are not as strong.  Tropical Cyclone Winston could continue to weaken slowly for another 12 to 24 hours.  It may re-intensify in about two or three days.

The subtropical ridge is likely to continue to steer Winston toward the northeast for anther two or three days.  After that time the subtropical ridge may shift position and allow Winston to turn back toward the west.  On its anticipated track Tropical Cyclone Winston could move over the extreme southeastern islands of Fiji on Monday.  It could bring strong winds, heavy rain and large surf to Vatoa, Ono-i-lau, Tuvana-i-colo, and Tuvana-i-ra.  Tropical Cyclone Winston could affect portions of Tonga during the middle of the week.

Tropical Cyclone Winston Turning East

Tropical Cyclone Winston turned eastward on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Winston was located at latitude 25.2°S and longitude 175.3°E which put it about 545 miles (880 km) south-southwest of Suva, Fiji.  Winston was moving toward the east-southeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 967 mb.

A subtropical ridge located north of Winston generated easterly winds over the top of the tropical cyclone.  The vertical wind shear caused Tropical Cyclone to weaken on Saturday.  Thunderstorms around the western side of the eyewall weakened and the eye became obscured at times as clouds blew over the top of it.  The vertical structure of the circulation is tilted toward the east with height because of the wind shear.  Tropical Cyclone Winston is likely to continue to weaken on Sunday.  However, it is moving over water where Sea Surface Temperature is near 29°C.  If the circulation maintains its integrity for another 48 hours, the wind shear could diminish and Winston could start to intensify again.

The subtropical ridge is steering Tropical Cyclone Winston toward the east.  The ridge is forecast to move toward the north and that will allow Winston to move more toward the northeast.  On its anticipated track Tropical Cyclone Winston could be near the southeastern islands of Fiji in about three days.

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.