Tag Archives: Fiji

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.

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.

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.

Strong Tropical Cyclone Amos Heading Toward Samoa

Tropical Cyclone Amos strengthened as it passed over Iles Wallis and headed toward Samoa on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Amos was located at latitude 12.5°S and longitude 175.4°E which put it about 70 miles (115 km) north-northeast of Iles Wallis and about 360 miles (580 km) west-northwest of Pago Pago, Samoa.  Amos was moving toward the east at 11 m.p.h. (18 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 956 mb.

The core of the circulation of Tropical Cyclone Amos is small but it is well organized.  There is a ring of the thunderstorms around an eye, but clouds from the taller thunderstorms are obscuring the eye on conventional satellite imagery.  Multiple bands of thunderstorms are rotating around the core of the circulation.  The thunderstorms are generating well developed upper level divergence which is pumping out mass in all directions.

Tropical Cyclone Amos is an environment favorable for further intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The winds in the upper levels are weak and there is not much vertical wind shear.  Amos is likely to intensify during the next 24 hours and it could be the equivalent of a major hurricane when it reaches the western part of Samoa.

A ridge of high pressure is expected to steer Tropical Cyclone Amos toward the east-southeast during the nest several days.  On its anticipated track Amos could be approaching the western islands of Samoa in a little over 24 hours.  It could be the equivalent of a major hurricane at that time.

The Hurricane Intensity Index (HII) for Amos is currently 17.8.  The Hurricane Size Index (HSI) is 9.0 and the Hurricane Wind Intensity Size Index (HWISI) is 26.8.  Those indices suggest that the core of Tropical Cyclone Amos will be capable of causing major damage if it moves directly over any of the islands of Samoa.  In addition, Amos will produce locally heavy rain capable of causing flash floods.  It could also generate high waves and surges along the coasts of some of the islands.

Tropical Cyclone Amos to Bring Wind and Rain to Wallis and Samoa

Tropical Cyclone Amos intensified to the equivalent of a hurricane/typhoon on Thursday as it moved eastward across the South Pacific.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Amos was located at latitude 12.4°S and longitude 177.1°W which put it about 80 miles (130 km) northwest of Iles Wallis.  Amos was moving toward the east-northeast at 11 m.p.h. (18 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 974 mb.

Tropical Cyclone Amos is a small, tightly organized storm.  A primary band of thunderstorms wraps almost entirely around the center of circulation and an eyelike feature is visible intermittently on satellite imagery.  Additional bands of showers and thunderstorms are spiraling around the core of the circulation.  The thunderstorms are generating upper level divergence which is pumping out mass in all directions and causing the surface pressure to decrease.

The environment around Tropical Cyclone Amos is very favorable for further intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are very weak and there is little vertical wind shear.  Amos will continue to intensify on Friday and it could intensify rapidly.

A subtropical ridge north of Amos is steering the tropical cyclone toward the east and that general motion is expected to continue for several more days.  On its anticipated track Amos will pass near Iles Wallis on Friday.  Although the core of strongest winds will pass north of Iles Wallis, It could still bring strong winds, heavy rain and large waves to those islands.  On its anticipated track Amos could be approaching western Samoa within 36 hours.  It could be a very strong tropical cyclone at that time.

Tropical Cyclone Amos Forms North of Fiji

A center of circulation developed within a large area of thunderstorms north of Fiji on Wednesday and the system was designated as Tropical Cyclone Amos.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Amos was located at latitude 12.5°S and longitude 179.4°W which put it about 145 miles (235 km) northwest of Ile Futuna.  Amos was stationary.  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 989 mb.

The circulation near the core of Tropical Cyclone Amos is still organizing.  A narrow primary band of thunderstorms is wrapping tightly around the core and an eye may be forming at the center of circulation.  Several other thin bands of showers and thunderstorms are rotating around the outer portions of the circulation.  The thunderstorms are generating some upper level divergence, but it is not well developed yet.

The environment is favorable for continued intensification.  Amos is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are not very strong and there is little vertical wind shear.  As the core of the circulation becomes more well organized, it will convert energy from the ocean more efficiently and the wind speeds will increase.  Tropical Cyclone Amos could intensify into the equivalent of a hurricane/typhoon within 24 to 36 hours.

Tropical Cyclone Amos is currently in an area where the steering currents are weak.  An upper level ridge is forecast to develop north of Amos and begin to steer the tropical cyclone toward the east.  On its anticipated track Amos could pass near Iles Wallis in 24 to 36 hours.  It could be approaching Samoa in two or three days.

Tropical Cyclone Zena Shears Apart South of Fiji

Strong upper level winds blew the upper portion of the circulation east of the surface circulation of Tropical Cyclone Zena as it passed south of Fiji.  At 8:00 p.m. EDT on Wednesday the center of Tropical Cyclone Zena was located at latitude 21.5°S and longitude 176.0°W which put it about 60 miles (95 km) west of Nuku’ Alofa, Tonga.  Zena was moving toward the east-southeast at 36 m.p.h. (58 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 988 mb.

Although Tropical Cyclone Zena briefly reached hurricane/typhoon intensity on Tuesday, it always consisted of a very small circulation which was very susceptible to vertical wind shear.  When an upper level ridge northeast of Zena increased west-northwesterly winds over the top of the tropical cyclone, those winds blew the upper portion of the circulation east of the center. The circulation of Zena lost its vertical integrity and it was difficult to find a well defined center of circulation at the surface by late Wednesday.  The remnants of Tropical Cyclone Zena are on a trend of rapid weakening.  The vertical wind shear is expected to continue and Zena could dissipate within 24 to 36 hours while it passes south of Niue.

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.