Tag Archives: 96P

Tropical Low Prompts Watch for Western Australia

The risk posed by a Tropical Low over the Timor Sea caused the Australian Bureau of Meteorology to issue a Watch for a portion of the coast of Western Australia on Friday.  At 11:00 a.m. EDT on Friday the center of the Tropical Low was located at latitude 9.8°S and longitude 129.1°E which put the center about 215 miles (350 km) northwest of Darwin, Australia.  The Tropical Low was moving toward the south-southwest at 7 m.p.h. (11 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.

A Watch was in effect for the portion of the coast of Western Australia from Cockatoo Island to the Berkeley River Mouth.  The Watch included Kalumburu and Kuri Bay.

The U.S. Joint Typhoon Warning Center was designating the Tropical Low as Invest 96P.

Vertical wind shear was causing the distribution of thunderstorms to be asymmetrical.  The Tropical Low as under the northern part of an upper level ridge that extended from Australia to the South Indian Ocean.  The upper level ridge was producing northeasterly winds that were causing the vertical wind shear.  Most of the thunderstorms were occurring in bands in the western half of the Tropical Low.  Bands in the eastern side of the Tropical Low consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence that pumped mass away to the west of the Tropical Low.  The removal of mass in the upper levels was nearly equal to the inflow of mass in the lower levels of the atmosphere.  The balance of inflow and outflow was causing the surface pressure to remain constant.

The Tropical Low will move through an environment somewhat favorable for intensification during the next 24 hours.  The Tropical Low will move over water where where the Sea Surface Temperatures are near 30°C.  The northern part of an upper level ridge over Australia and the South Indian Ocean will continue to produce northeasterly winds that will blow toward the top of the Tropical Low.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the Tropical Low is likely to intensify gradually during the next 24 hours.

The Tropical Low will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer the Tropical Low toward the southwest during the next 24 hours.  On its anticipated track, the low pressure system will move away from Darwin.  The low pressure system could pass near Cape Londonderry and Cape Bougainville on Saturday.

 

Tropical Cyclone Forming Over Timor Sea

A tropical cyclone was forming over the Timor Sea on Thursday morning.  A low pressure system was gradually organizing into a tropical cyclone over the Timor Sea north of Darwin, Australia on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of the low pressure system was located at latitude 8.7°S and longitude 130.3°E which put the center about 270 miles (435 km) north of Darwin, Australia.  The low pressure system was moving toward the southwest at 7 m.p.h. (11 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 1001 mb.

A low pressure system over the Timor Sea north of Darwin, Australia exhibited more organization on Thursday morning.  More thunderstorms formed near the center of the low pressure system.  More thunderstorms also developed in bands revolving around the center of circulation.  Storms near the center of circulation began to generate upper level divergence that pumped mass away from the low pressure system.  The removal of mass caused the surface pressure to decrease.

The low pressure system will move through an environment favorable for the formation of a tropical cyclone during the next 24 hours.  The low pressure system will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the northern part of an upper level ridge over Australia and the South Indian Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of the low pressure system.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the low pressure system is likely to develop into a tropical cyclone during the next 24 hours.

The low pressure system will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer the low pressure system toward the southwest during the next 24 hours.  On its anticipated track, the low pressure system will move away from Darwin.  The low pressure system could pass near Cape Londonderry and Cape Bougainville.

Tropical Low Brings Wind and Rain to Northern Australia

A Tropical Low pressure system brought wind and rain to northern Australia on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of the Tropical Low was located at latitude 12.1°S and 131.5°E which put it about 45 miles (75 km) east-northeast of Darwin, Australia.  The Tropical Low was moving toward the west-southwest at 8 m.p.h. (12 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.

The circulation of the Tropical Low is not very well organized.  Many of the thunderstorms are occurring in the outer portions of the circulation.  There are mostly showers, and only a few thunderstorms, near the center of circulation.  There are a few rainbands near the periphery of the circulation, but there is not a well formed core at the center.  The poor organization is preventing the Tropical Low from generating much upper level divergence and as a result the surface pressure has changed little during the past 24 hours.

A significant portion of the circulation of the Tropical Low is over land and that is inhibiting development of the system.  In addition, an upper level ridge to the east of the Tropical Low is producing northerly winds which are blowing across the top of the circulation.  Those winds are causing moderate vertical wind shear which is also inhibiting development.  The Tropical Low is moving toward the west-southwest and the center is forecast to move over the Timor Sea.  If the center of circulation moves over the Timor Sea, it will move over water where the Sea Surface Temperature is near 30°C.  More energy from the water could offset the effects of the vertical wind shear and the Tropical Low could intensify into a tropical cyclone.

A subtropical ridge east of the Tropical Low is steering the system toward the west-southwest and that general motion is expected to continue during the next several days.  On its anticipated track the center of the Tropical Low will move near the northern coast of Australia.  If the center emerges over the Timor Sea, then the system could intensify into a tropical cyclone.  If the center remains over land, then further development will not occur.  In either case the Tropical Low will bring gusty winds and heavy rains to the northern coastal regions of the Northern Territory and Western Australia.