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Tropical Cyclone Pita Forms West of Niue

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Tropical Cyclone Pita formed over the South Pacific Ocean west of Niue on Friday.  At 1:00 p.m. EST on Friday the center of Tropical Cyclone Pita was located at latitude 18.5°S and longitude 172.2°W which put the center about 155 miles (250 km) west-northwest of Niue.  Pita was moving toward the east-southeast at 14 m.p.h. (22 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 991 mb.

A low pressure system over the South Pacific Ocean west of Niue strengthened on Friday and the Fiji Meteorological Service designated the system as Tropical Cyclone Pita.  The circulation around Tropical Cyclone Pita organized quickly on Friday.  The inner end of a rainband wrapped around the eastern and southern sides of the center of Pita’s circulation.  Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Pita.  Storms near the center of Pita generated upper level divergence that pumped mass away from the tropical cyclone.

Tropical Cyclone Pita will move through an environment favorable for intensification during the next 24 hours.  Pita will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level ridge over the South Pacific Ocean.  The upper level ridge will produce westerly winds that will blow toward the top of Pita’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Cyclone Pita is likely to intensify during the next 24 hours.

Tropical Cyclone Pita will move around the northern side of a high pressure system over the South Pacific Ocean.  The high pressure system will steer Pita toward the east-southeast during the next 24 hours.  On its anticipated track, the center of Tropical Cyclone Pita will reach Niue in less than 12 hours.

Tropical Cyclone PIta will bring strong winds and heavy rain to Niue.  Heavy rain is likely to cause flash floods in some locations.

Tropical Low Forms over Timor Sea

A Tropical Low formed over the Timor Sea northwest of Darwin Australia on Saturday. At 8:00 a.m. EDT on Saturday the center of the Tropical Low was located at latitude 10.3°S and longitude 129.0°E which put it about 105 miles (165 km) northwest of Darwin, Australia. The Tropical Low was moving toward the southwest at 6 m.p.h. (9 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 996 mb.

A Tropical Cyclone Watch was in effect for the portion of the coast of Western Australia from Kalumburu to Cockatoo Island.

A low pressure system over the Timor Sea northwest of Darwin, Australia strengthened on Saturday morning and the Australian Bureau of Meteorology designated the system as a Tropical Low. The distribution of thunderstorms around the Tropical Low was asymmetrical. Most thunderstorms were occurring in bands in the western half of the circulation. Bands in the eastern side of the Tropical Low consisted primarily of showers and lower clouds. The Tropical Low was moving under the northern part of an upper level ridge over northern Australia. The ridge was producing easterly winds that were blowing toward the top of the Tropical Low. Those winds were causing moderate vertical wind shear and the wind shear was causing the asymmetrical distribution of thunderstorms. Storms near the center of circulation generated upper level divergence that pumped mass away to the west of the tropical low.

The Tropical Low will move through an environment that will be somewhat favorable for intensification during the next 36 hours. The Tropical Low will move over water where the Sea Surface Temperatures are near 31˚C. However, the upper level ridge over northern Australia will continue to cause moderate vertical wind shear. The Tropical Low is likely to intensify gradually during the next 36 hours. It could become a named tropical cyclone during that time.

The Tropical Low will move around the northwest part of a high pressure system over western Australia. The high pressure system will steer the Tropical Low toward the southwest during the next 36 hours. On its anticipated track, the Tropical Low will move parallel to the coast of Western Australia during the weekend.

Tropical Cyclone 05S Forms Over Mozambique Channel

A surface circulation organized quickly inside a low pressure system over the Mozambique Channel on Sunday and the system was designated as Tropical Cyclone 05S.  At 7:00 p.m. EST on Sunday the center or Tropical Cyclone 05S was located at latitude 21.6°N and longitude 39.9°E which put it about 540 miles (870 km) northeast of Maputo, Mozambique.  Tropical Cyclone 05S was moving toward the south-southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

Tropical Cyclone 05S has a tight center of circulation, but the distribution of thunderstorms is asymmetrical.  Multiple bands of thunderstorms developed in the eastern half of the circulation.  The strongest winds are occurring in the bands of thunderstorms.  However, there are mainly showers and a few isolated thunderstorms in the bands in the western half of the circulation.  The thunderstorms in the bands east of the center of circulation are beginning to generate upper level divergence.

Tropical Cyclone 05S will be moving through a favorable environment during the next several days.  It will be moving over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone 05S is underneath an upper level ridge.  The upper level winds are weak and there is not much vertical wind shear.  There may be some drier air in the western half of the circulation and that is the only inhibiting factor in the environment around Tropical Cyclone 05S.  Given the mostly favorable environment Tropical Cyclone 05S is likely to intensify during the next day or two.  If an inner core becomes fully developed, then a period of rapid intensification may be possible.

Tropical Cyclone 05S is currently in an area of weak steering currents because of its position underneath the upper level ridge.  Some global models are indicating that a track toward the southwest could be possible if the tropical cyclone moves closer to the western portion of the ridge.  On its anticipated track Tropical Cyclone 05S could move in the general direction of Mozambique.