Category Archives: South Pacific

Tropical Cyclone Fehi Develops Near New Caledonia

Tropical Cyclone Fehi developed over the Coral Sea near New Caledonia on Sunday.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Fehi was located at latitude 19.7°S and longitude 162.2°E which put it about 360 miles (580 km) northwest of Noumea, New Caledonia.  Fehi was moving toward the south-southeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 60 m.p.h. (90 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 982 mb.

The circulation of Tropical Cyclone Fehi was not well organized for much of Sunday, but it exhibited signs of greater organization in recent hours.  An upper level low near eastern Australia was producing strong northwesterly winds that were blowing over the top of the circulation.  Those winds caused strong vertical wind shear for much of Sunday, but the shear appeared to decrease on Sunday night.  A distinct low level center of circulation was exposed on recent visible satellite images.  Most of the thunderstorms were occurring in bands south of the center of circulation.  More bands of showers and low clouds seemed to be forming in the northern half of the circulation.  A rainband appeared to be wrapping around the northern side of the circulation.  There was some upper level divergence to the southeast of Tropical Cyclone Fehi.

Tropical Cyclone Fehi will be moving through an environment that will be marginally favorable for intensification during the next day or two.  Fehi is moving over water where the Sea Surface Temperature is near 28°C.  The upper level low will continue to cause vertical wind shear, but the shear may be small enough to allow for intensification.  Tropical Cyclone Fehi could intensify during the next 24 hours.  When Fehi moves farther south, it will move over much cooler water and the tropical cyclone will start to weaken.  Tropical Cyclone Fehi could make a transition to an extratropical cyclone in two or three days.

The upper low near eastern Australia is steering Tropical Cyclone Fehi toward the south-southeast.  A general motion toward the southeast is expected during the next two or three days.  On its anticipated track the center of Tropical Cyclone Fehi is forecast to pass west of New Caledonia.  Although the center is likely to pass to the west of New Caledonia, rainbands on the eastern side of Fehi could bring gusty winds and locally heavy rain.  Heavy could cause flash floods.  Tropical Cyclone Fehi could approach New Zealand in about three days.  Fehi could be a strong extratropical cyclone at that time.

Weaker Tropical Cyclone Ella Passing North of Fiji

Tropical Cyclone Ella weakened on Saturday as passed north of Fiji.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Ella was located at latitude 12.9°S and longitude 178.9°E which put it about 365 miles (585 km) north-northeast of Nadi, Fiji.  Ella was moving toward the west at 5 m.p.h. (8 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 1001 mb.

Tropical Cyclone Ella moved underneath an area of stronger upper level westerly winds on Saturday.  Stronger vertical wind shear pushed the upper part of the circulation east of the lower level circulation.  The center of the lower level circulation was completely exposed by late Saturday.  It consisted of a tight swirl of low clouds and showers.  Some thunderstorms were occurring in bands east of the low level center.

The small size of Tropical Cyclone Ella made it very vulnerable to increased vertical wind shear.  Tropical Cyclone Ella is forecast to continue to move under the upper level westerly winds.  Shear is likely to weaken Ella further even though it will move over water where the Sea Surface Temperature is near 30°C.

A subtropical ridge south of Ella is steering the tropical cyclone toward the west and that general motion is expected to continue.  Tropical Cyclone Ella is forecast to move through Tuvalu, but it will pass north of Fiji.

Tropical Cyclone Ella Strengthens To Equivalent of a Hurricane Near Wallis & Futuna

Tropical Cyclone Ella strengthened into the equivalent of a hurricane/typhoon as it moved near Wallis and Futuna on Thursday.  Ella brought gusty winds and locally heavy rain to those islands.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Ella was located at latitude 14.0°S and longitude 178.2°W which put it about 20 miles (30 km) north of Wallis and Futuna.  Ella was moving toward the northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 979 mb.

Tropical Cyclone Ella has a very small circulation, but that circulation is well organized.  There is a very tight inner core.  A ring of strong thunderstorms surrounds a tiny pinhole eye.  The strongest winds are occurring in the tight eyewall.  Additional bands of thunderstorms are forming in the eastern half of the circulation.  There are bands of showers in the western half of the circulation.  Winds to hurricane/typhoon force extend out only about 10 miles (15 km) from the center of circulation.  Winds to tropical storm force extend out about 80 miles (130 km) from the center.

Tropical Cyclone Ella is moving through an environment favorable for intensification.  Ella is moving over water where the Sea Surface Temperature is near 30°C.  It is in an area where the upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Ella could continue to intensify as long as it is in an area where the upper level winds are weak.  However, there are much strong upper level westerly winds flowing just to the south of the tropical cyclone.  If Tropical Cyclone Ella moves into an area where the upper level winds are strong, vertical wind shear could weaken it very quickly because of Ella’s small size.

A subtropical ridge south of Ella is steering the tropical cyclone toward the west and a general westerly motion is expected to continue for several more days.  On its anticipated path Tropical Cyclone Ella will move away from Wallis and Futuna.  Ella could move near the northeastern portion of Fiji in 24 to 36 hours.

Tropical Cyclone Ella Strengthens As It Nears Wallis and Futuna

Tropical Cyclone Ella strengthened on Wednesday as it moved closer to Wallis and Futuna.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Ella was located at latitude 14.4°S and longitude 177.0°W which put it about 75 miles (120 km) east of Wallis and Futuna.  Ella was moving toward the west 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 989 mb.

The circulation of Tropical Cyclone Ella exhibited better organization on Wednesday.  A circular eye with a diameter of 25 miles (40 km) was evident on some microwave satellite images.  A ring of thunderstorms surrounded the eye.  Additional bands of showers and thunderstorms developed in the eastern half of the circulation.  Storms in the core of the circulation generated upper level divergence which pumped out mass and allowed the surface pressure to decrease.  The size of the circulation of Tropical Cyclone Ella is small.  Winds to tropical storm force only extend out about 100 miles (160 km) fro the center of circulation.

Tropical Cyclone Ella will move through an area that will be favorable for intensification.  Ella will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Ella could intensify into the equivalent of a hurricane/typhoon on Thursday.  However, because the size of the circulation is small, any future increase in the vertical wind shear could quickly weaken Tropical Cyclone Ella.

Ella is moving around the northern side of a subtropical ridge, which is steering the tropical cyclone toward the west.  Ella is currently moving north of a weaker section of the ridge and the steering winds are weaker.  So, Ella is moving more slowly.  The ridge is expected to steer Tropical Cyclone Ella in a general westerly direction during the next several days.  On its anticipated track Tropical Cyclone Ella could pass near Wallis and Futuna in 12 to 18 hours.  It could be near hurricane/typhoon strength at that time.  Ella could approach the northeastern part of Fiji in two or three days.

Tropical Cyclone Donna Brings Wind and Rain to New Caledonia

Tropical Cyclone Donna brought wind and rain to New Caledonia as it moved over that region.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Donna was located at latitude 19.9°S and longitude 166.8°E which put it about 185 miles (295 km) north of Noumea, New Caledonia.  Donna was moving toward the south-southeast at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (215 km/h).  The minimum surface pressure was 962 mb.

The inner core of Tropical Cyclone Donna remained intact despite increased vertical wind shear on Monday.  A well formed circular eye with a diameter of 30 miles (50 km) was evident on microwave satellite images.  A ring of strong thunderstorms wrapped around the eye.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  The size of the circulation of Tropical Cyclone Donna increased on Monday.  Winds to hurricane/typhoon force extend out about 80 miles (130 km) on the eastern side of the center and about 45 miles (75 km) on the western side.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Donna was 19.2.  The Hurricane Size Index (HSI) was 23.3 and the Hurricane Wind Intensity Size Index was 42.5.  These indices suggest that Tropical Cyclone Donna is very similar in size and intensity to Hurricane Gustav in 2008 just before Gustav made landfall in Louisiana.

Tropical Cyclone Donna will weaken during the next several days.  An upper level trough is approaching it from the west.  The upper level trough is generating northwesterly winds which are blowing toward the top of the circulation.  The northwesterly winds are inhibiting upper level divergence to the west of Donna and moderate vertical wind shear will continue to weaken the tropical cyclone.  In addition Tropical Cyclone Donna will move over cooler SSTs when it moves farther south.

The winds in the upper level trough are pushing Tropical Cyclone Donna toward the south-southeast.  That general motion is expected to continue during the next several days.  On its anticipated track the core of Tropical Cyclone Donna will move over the Iles Loyaute (Loyalty Islands).  Donna will bring strong gusty winds winds to those islands.  In addition rainbands will bring wind and heavy rain to parts of New Caledonia.  Tropical Cyclone Donna is capable of causing widespread serious damage.

Tropical Cyclone 19P Forms Southwest of Samoa

Tropical Cyclone 19P formed southwest of Samoa on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone 19P was located at latitude 15.2°S and longitude 173.3°W which put it about 100 miles (160 km) southwest of Apia, Samoa.  It was moving toward the west-northwest at 6 m.p.h. (10 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 1000 mb.

A small tight center of circulation formed within an area of thunderstorms south of Samoa on Monday.  A thin primary rainband wrapped tightly around the center of circulation.  Additional bands of showers and thunderstorms developed in the east half of the circulation.  The bands of showers in the western part of the tropical cyclone were much weaker.  Thunderstorms in the core of the circulation generated upper level divergence which pumped out mass.  The circulation of Tropical Cyclone 19P is small.  Winds to tropical storm force only extend out about 40 miles (65 km) from the center of circulation.

Tropical Cyclone 19P will be moving through an environment that will be marginally favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone 19P is under the eastern end of an upper level ridge which is producing southerly winds that are blowing toward toward the top of the circulation.  The upper level winds are generating moderate vertical wind shear which is inhibiting upper level divergence to the south of the tropical cyclone.  Given the marginal conditions Tropical Cyclone 19P could maintain its intensity or slowly strengthen.  However, since the circulation is so small, a significant increase in vertical wind shear could also quickly weaken the tropical cyclone.

The same subtropical ridge that steered Tropical Cyclone Donna is also steering Tropical Cyclone 19P toward the west-northwest.  A general westerly motion is expected for the next two or three days.  On its anticipated track Tropical Cyclone 19P could approach Fiji in about 48 hours.

Powerful Tropical Cyclone Donna Moves Toward New Caledonia

Powerful Tropical Cyclone Donna moved toward New Caledonia on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Donna was located at latitude 17.2°S and longitude 164.9°E which put it about 340 miles (550 km) north of Noumea, New Caledonia.  Donna was moving toward the south at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 135 m.p.h. (220 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 942 mb.

Tropical Cyclone Donna intensified rapidly into the equivalent of a major hurricane on Sunday.  The core of Donna is very well organized.  A ring of strong thunderstorms surrounds a circular eye which has a diameter of 35 miles (55 km).  Additional bands of showers and thunderstorms are occurring in the eastern half of the circulation.  Thunderstorms around the eye are generating strong upper level divergence which is pumping out mass.  Winds to hurricane/typhoon force extend out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extend out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Donna was 26.7.  The Hurricane Size Index (HSI) was 17.5 and the Hurricane Wind Intensity Size Index (HWISI) was 44.2.

Tropical Cyclone Donna will move through an environment that will become less favorable for intensification during the next several days.  Donna will move over water where the Sea Surface Temperature is near 27°C.  It is currently in an area where upper level winds are weak and there is little vertical wind shear.  However, an upper level trough is approaching from the west.  Stronger northwesterly winds associated with the upper level trough will increase the vertical shear during the next several days and Tropical Cyclone Donna will weaken when the shear increases.

Donna is at the western end of a subtropical ridge which is steering the tropical cyclone slowly toward the south.  The approaching upper level trough will turn Tropical Cyclone Donna more toward the southeast in 12 to 24 hours.  On its anticipated track the center of Tropical Cyclone Donna could approach the Iles Loyaute in about 24 hours.  Donna could move near the southern portion of New Caledonia within 36 hours.

Tropical Cyclone Donna could bring strong gusty winds and locally heavy rains to portions of New Caledonia.  Donna could also generate a storm surge on the Iles Loyaute and on parts of the southern coast of New Caledonia.

Tropical Cyclone Donna Turns South As Eye Forms

An eye formed at the center of Tropical Cyclone Donna as it turned southward on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Donna was located at latitude 14.1°S and longitude 164.1°E which put it about 390 miles (625 km) northwest of Port Vila, Vanuatu.  Donna was moving toward the south 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 120 m.p.h. (205 km/h).  The minimum surface pressure was 965 mb.

A primary rainband finally wrapped around the center of circulation on Saturday and a circular eye appeared on visible satellite imagery.  Additional bands of showers and thunderstorms revolved around the core of Tropical Cyclone Donna.  Thunderstorms in the core of the tropical cyclone generated strong upper level divergence which pumped out mass.  Winds to hurricane/typhoon force extended out about 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out about 185 miles (295 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Donna was 17.8.  The Hurricane Size Index (HSI) was 14.4 and the Hurricane Wind Intensity Size Index (HWISI) was 32.2.

Tropical Cyclone Donna will move through an environment favorable for intensification for another 24 to 36 hours.  Donna will move over water where the Sea Surface Temperature is near 29°C.  Donna is moving near the western end of a upper level ridge and there are light northerly winds blowing toward the top of the circulation.  There is little vertical wind shear.  Tropical Cyclone Donna is likely to intensify during the next 24 hours.  The formation of an eye and a more organized inner core could allow Tropical Cyclone Donna to convert energy more efficiently and a period of rapid intensification is possible.  Tropical Cyclone Donna is likely to intensify into the equivalent of a major hurricane during the next day or so.

Tropical Cyclone Donna moved slowly westward as it neared the western end of a subtropical ridge.  Donna appears to have reached the end of the ridge and it has turned southward.  The tropical cyclone is likely to move south for another 24 hours.  A upper level trough will approach Donna from the west in about a day and northwesterly winds in the leading side of the trough are likely to push Donna southeast at a faster speed.  The westward movement of Tropical Cyclone Donna during the past several days reduced the potential threat to Vanuatu.  However, that same motion increased the potential threat to New Caledonia.

Rainbands in the eastern half of Tropical Cyclone Donna are likely to bring gusty winds and locally heavy rain to Vanuatu, but the core and strongest winds are likely to stay west of those islands.  On its anticipated track Tropical Cyclone Donna could approach New Caledonia in 36 to 48 hours.  The core of Tropical Cyclone Donna could pass over the Iles Loyaute.

Stronger Tropical Cyclone Donna Moves North of Vanuatu

Tropical Cyclone Donna strengthened on Thursday as it moved north of Vanuatu.  The center of Donna passed near the Banks Islands and the Torres Islands and it is currently located northwest of Espiritu Santo.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Donna was located at latitude 13.2°S and longitude 166.0°E which put it about 350 miles (560 km) north-northwest of Port Vila, Vanuatu.  Donna was moving toward the west-southwest at 7 m.p.h. (11 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 967 mb.

A partial eyewall continued to wrap around the center of circulation, but a well defined eye did not form.  A band of thunderstorms extended about two thirds of the way around the center.  Other bands of showers and thunderstorms were revolving around the core of the circulation.  Thunderstorms near the core of the circulation generated upper level divergence that pumped out mass to the southeast of Tropical Cyclone Donna.

Winds to hurricane/typhoon force extend out about 40 miles (65 km) from the center of circulation and winds to tropical storm force extend out about 140 miles (225 km) from the center.  The Hurricane Intensity Index (HII) is 16.5.  The Hurricane Size Index (HSI) is 13.4 and the Hurricane Wind Intensity Size Index (HWISI) is 29.9.

Tropical Cyclone Donna will move through an area that will be somewhat favorable for intensification.  Donna will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of Donna is producing northerly winds which are blowing toward the top of the tropical cyclone.  The upper level winds are generating moderate vertical wind shear and the shear seems to have slowed the intensification of Donna.  The strength of the upper level winds could decrease and intensification could resume on Friday.  Tropical Cyclone Donna could intensify into the equivalent of a major hurricane during the next 24 to 48 hours.

A subtropical ridge to the south of Donna is steering the tropical cyclone toward the west-southwest and that general motion is expected to continue for about another 24 hours.  Tropical Cyclone Donna will reach the western end of the ridge in about a day or so and it will turn toward the south.  On its anticipated track the center of Tropical Cyclone Donna will pass west of Espiritu Santo.  Guidance from the numerical models suggests the center of Donna could pass between Vanuatu and New Caledonia, but different models are predicting different tracks and so there is more uncertainty in the track at that time.

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.