Category Archives: Australian Region

Former Tropical Cyclone Hilda Drops Heavy Rain Over Western Australia

Former Tropical Cyclone Hilda dropped heavy rain over Western Australia on Friday.  At 11:00 a.m. EST on Friday the center of former Tropical Cyclone Hilda was located at latitude 22.7°S and longitude 123.6°E which put it about 50 miles (80 km) east-northeast of Telfer, Australia.  Hilda was moving toward the southeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 999 mb.

Although the center has been over land for more than a day, the circulation of former Tropical Cyclone Hilda is still well organized.  There is a well defined low level center of circulation and strong thunderstorms are occurring around the center.  Several bands of thunderstorms are revolving around the core of the circulation.  Storms near the core are generating strong upper level divergence which is pumping away mass.  The upper level divergence is preventing the surface pressure from increasing and that is allowing the surface low to maintain its intensity.

Storms near the core of former Tropical Cyclone Hilda and the rainbands are dropping heavy rain over parts of Western Australia.  That region is normally dry and the potential for flash floods exists.  The Australian Bureau of Meteorology has issued Flood Warnings for the Sandy Desert and West Kimberly District.  They have also issued Flood Watches for the De Grey River, Salt Lakes and Warburton District Catchments.  The storms generated by former Tropical Cyclone Hilda could also cause localized wind damage, but the greatest risk is posed by the heavy rain.

Tropical Cyclone Hilda Develops on Coast of Western Australia

A Tropical Low near the coast of Western Australia strengthened and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Hilda. At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Hilda was located at latitude 18.0°S and longitude 122.1°E which put it about 10 miles (15 km) west-southwest of Broome, Australia.  Hilda was moving toward the south-southwest at 8 m.p.h. (12 km/h).  The maximum sustained wind speed was 50 m.p.h. (85 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 985 mb.  Broome Port reported a wind gust to 86 m.p.h. (139 km/h).

The center of the Tropical Low moved off the coast of Western Australia and the core of the circulation strengthened.  Thunderstorms in the core of Tropical Cyclone Hilda generated strong upper level divergence which pumped mass away from the center of circulation.  The removal of mass allowed the surface pressure to decrease quickly and the wind speeds increased.  The strongest winds were occurring over water near the center of circulation.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  Hilda is a small tropical cyclone.  Winds to tropical storm force only extend out about 35 miles (55 km) from the center of circulation.

Tropical Cyclone Hilda will be moving through an environment that will support further intensification during the next 12 hours.  The Sea Surface Temperature of the water near the coast of Western Australia is near 30°C.  Tropical Cyclone Hilda is underneath an upper level ridge and the upper level winds are weak.  There is little vertical wind shear.  The proximity to land is the only factor preventing rapid intensification of Tropical Cyclone Hilda.  Almost half of the circulation is over land and the increased friction is reducing the wind speeds in that part of Tropical Cyclone Hilda.

Tropical Cyclone Hilda is moving around the western end of a subtropical ridge, which is steering the tropical cyclone toward the south-southwest.  A general motion toward the south-southwest is expected to continue for another 12 to 24 hours.  On its anticipated track the center of Tropical Cyclone Hilda could pass near Bidyadanga during the next 6 to 12 hours.  Hilda will bring gusty winds capable of producing localized minor wind damage.  A Warning is in effect for the portion of the coast from Beagle Bay to Pardoo Roadhouse.  The core of Tropical Cyclone Hilda will drop locally heavy rain near the coast of Western Australia and flash flooding is possible.

Tropical Low Develops Near Coast of Western Australia

A distinct low level center of circulation developed in an area of thunderstorms near the coast of Western Australia on Tuesday and the Australian Bureau of Meteorology classified the system as a Tropical Low.  At 10:00 p.m. EST on Tuesday the center of the Tropical Low as located at latitude 17.2°N and 122.3°E which put it just inland east of Coulomb Point and about 55 miles (85 km) north of Broome, Australia.  The Tropical Low was moving toward the southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

Although the center of circulation was over land, the circulation of the Tropical Low became much better organized on Tuesday.  There was a well defined center of circulation and weather radar images indicated an eyelike feature at the center of the Tropical Low.  Several bands of showers and thunderstorms wrapped around the center of circulation.  Storms in the core of the Tropical Low were generating well developed upper level divergence which was pumping mass away in all directions.

The Tropical Low will move through an environment favorable for intensification during the next 24 to 36 hours.  The Sea Surface Temperature of the water off the coast of Western Australia is near 30°C.  The Tropical Low is underneath an upper level ridge and the upper level winds are not very strong.  There is little vertical wind shear.  The only factor inhibiting intensification is the fact that the center is still inland over Western Australia.  If the center moves over water as is forecast, the Tropical Low will intensify and it could intensify rapidly.

The Tropical Low is moving around the western end of a mid-level ridge which is steering it toward the southwest.  The ridge is forecast to steer the Tropical Low toward the southwest for another 12 to 24 hours.  When the Tropical Low reaches the western end of the ridge, it will move more toward the south.  On its anticipated track the center of the Tropical Low will move off the coast of Western Australia and over water during the next 6 to 12 hours.  The center of the Tropical Low is expected to pass west of Broome.  The Tropical Low could approach the coast of Western Australia between Bidyadanga and Wallal Downs in about 36 hours.

The Tropical Low will drop heavy rain along the coast of Western Australia during the next 48 hours.  It will also bring gusty winds and a Warning has been issued for the portion of the coast from Cape Leveque to De Grey.

Tropical Cyclone Dahlia Forms Southwest of Indonesia

Tropical Cyclone Dahlia formed southwest of Indonesia on Wednesday.  At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Dahlia was located at latitude 8.4°S and longitude 101.5°E which put it about 320 miles (520 km) west-northwest of Christmas Island.  Dahlia was moving toward the east at 5 m.p.h. (8 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 999 mb.

A center of circulation developed in a cluster of thunderstorms previously designated as Invest 96S and the Australian Bureau of Meteorology named the system Tropical Cyclone Dahlia.  The circulation of Dahlia is still organizing.  A primary rainband wrapped around the southern and western sides of the center.  Additional bands of showers and thunderstorms formed in the western half of the circulation.  Fewer thunderstorms formed in the eastern half of Dahlia.  The thunderstorms near and to the west of the center were generating upper level divergence which was pumping mass away to the west of the tropical cyclone.

Tropical Cyclone Dahlia will be moving through an environment favorable for intensification during the next several days.  Dahlia will move over water where the Sea Surface Temperature is near 29°C.  Dahlia is underneath the northern part of an upper level ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear, which may be the reason why most of the thunderstorms are west of the center of circulation.  The shear is strong enough to slow the intensification of Dahlia, but it is not strong enough to prevent the tropical cyclone from strengthening.  Tropical Cyclone Dahlia is likely to likely to intensify during the next 24 to 48 hours.

The steering winds around Dahlia are relatively weak and the tropical cyclone is moving slowly toward the east.  The upper level ridge is forecast to shift north and stronger westerly winds are likely to steer Tropical Cyclone Dahlia toward the east at a faster speed.  When Dahlia reaches the southern portion of the upper level ridge in a couple of days, northerly winds diverging from the ridge are likely to steer the tropical cyclone toward the south.

Tropical Cyclone Cempaka Develops South of Java

The organization of a small area of low pressure (also known as Invest 95S) south of Java increased early on Monday and the Badan Meteorologi Klimatologi Dan Geofisika (BMKG) Tropical Cyclone Warning Center in Jakarta designated the system as Tropical Cyclone Cempaka.  At 7:00 a.m. EST on Monday the center of Tropical Cyclone Cempaka was located at latitude 8.8°S and longitude 110.8°E which put it about 70 miles (115 km) south-southeast of Yokyakarta, Indonesia.  Cempaka was moving toward the east- northeast at 5 m.p.h. (8 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 997 mb.

Tropical Cyclone Cempaka has a small but well developed center of circulation.  Radar images from BKMG showed an eyelike feature at the center of circulation.  The strongest winds are occurring in a ring of showers and thunderstorms that surrounds the center.  The stronger storms are in the eastern half of the ring.  Other narrow rainbands are developing outside the core of Cempaka.  Thunderstorms around the center are generating some upper level divergence which is pumping mass away from the tropical cyclone.  Winds to tropical storm force extend out about 40 miles (65 km) from the center of circulation.

Tropical Cyclone Cempaka will be in an environment somewhat favorable for intensification during the next 24 to 48 hours.  Cempaka will move over water where the Sea Surface Temperature is near 29°C.  Tropical Cyclone Cempaka is under an upper level ridge and the upper level winds are weak.  There is little vertical wind shear over the tropical cyclone.  The core of Tropical Cyclone Cempaka is near Java.  Part of the circulation is flowing over Java and nearby islands and friction from those islands is slowing the winds.  Interaction with land is the primary factor inhibiting intensification.  If the center of Tropical Cyclone Cempaka remains south of Java, then it has a chance to intensify.  If Cempaka moves closer to Java, then it could weaken.  Also, since Cempaka is a very small tropical cyclone, an increase in the speed of the upper level winds could blow the top off of the circulation.

Since Tropical Cyclone Cempaka is underneath an upper level ridge, the steering winds are weak.  Cempaka is south of the center of the ridge and weak westerly winds are steering the tropical cyclone slowly toward the east-northeast.  Tropical Cyclone Cempaka is forecast to meander south of Java for several more days because of the weak stearing winds.

Tropical Cyclone Cempaka is producing locally heavy rain over parts of Java, Bali and nearby islands.  The locally heavy rain could cause flash floods as Cempaka meanders south of Java during the next day or two.

Low Pressure System Forms South of Java

A small, but well organized area of low pressure developed just to the south of Java on Sunday.  The low pressure system is currently designated as Invest 95S, but it could become a tropical cyclone during the next several days.  At 10:00 p.m. EST on Sunday the center of Invest 95S was located at latitude 8.9°S and longitude 109.8°E which put it about 100 miles (160 km) southwest of Yogyakarta, Indonesia.  It was moving toward the northeast at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 998 mb.

The circulation of Invest 95S is small but well formed.  There is a distinct low level center of circulation.  Two well formed narrow rainbands wrapped around the southern and northeastern sides of the center.  Other rainbands developed just outside the core of the circulation.  Storms near the center of circulation were generating some upper level divergence which was pumping out mass and allowing the surface pressure to decrease.

Invest 95S will move through an environment that is mostly favorable for intensification.  It will move over water where the Sea Surface Temperature is near 29°C.  Invest 95S is near the center of an upper level ridge.  The upper level winds blowing over the top of the low pressure system are weak and there is not a lot of vertical wind shear.  The proximity of the circulation to Java is the only factor likely to inhibit intensification.  If the center of circulation remains south of Java, then there is a good chance it could intensify into a tropical cyclone.

The ridge north of Invest 95S is steering the system slowly toward the northeast and a general easterly motion is expected to continue during the next 24 hours.  Guidance from numerical models diverges in a day or so.  Some models to suggest the northeasterly motion will continue and the low pressure system will move across Java.  Other models predict a turn toward the south in a day or so.  There is a high degree of uncertainty about the future track of Invest 95S.

Tropical Cyclone Frances Intensifies Into Equivalent of a Hurricane

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon on Friday as it moved northwest of Australia.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Frances was located at latitude 12.6°S and longitude 124.1°E which put it about 200 miles (325 km) north of Kuri Bay, Australia.  Frances was moving toward the west-southwest at 9 m.p.h. (14 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 981 mb.

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon when it moved through a favorable environment.  Frances moved over water where the Sea Surface Temperature (SST) was near 30°C and the upper level winds were weak.  A primary rainband wrapped almost entirely around the center of circulation and an eyelike feature seemed to be indicated on some satellite imagery.  Thunderstorms around the eye generated upper level divergence which pumped out mass and the circulation assumed a more symmetrical circulation.  Other bands of showers and thunderstorms formed in the outer portions of the circulation.

Tropical Cyclone Frances may have reached its peak intensity.  Frances will continue to move over water where the SST is near 30°C.  However, it is about to move near the western end of an upper level ridge where there are stronger northerly winds.  Those stronger winds will create much more vertical wind shear and Tropical Cyclone Frances is likely to weaken during the next several days.

A subtropical ridge to the east of Frances is steering the tropical cyclone toward the west-southwest and that general motion is forecast to continue for the next several days.  On its anticipated track Tropical Cyclone Frances poses no threat to Western Australia, although it could cause increased wave action along the coast.

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.

Tropical Cyclone Ernie Rapidly Intensifies Into the Equivalent of a Hurricane

The circulation of Tropical Cyclone Ernie rapidly intensified into the equivalent of a hurricane/typhoon late on Thursday.  At 8:00 p.m. EDT on Thursday the center of Tropical Cyclone Ernie was located at latitude 14.9°S and longitude 110.5°E which put it about 540 miles (870 km) north-northwest of Exmouth, Australia.  Ernie was moving toward the south-southwest at 8 m.p.h. (12 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 987 mb.

An area of thunderstorms just west of the center of circulation quickly wrapped around the entire center.  A clear eye formed at the center of circulation.  Additional bands of storms formed and were revolving around the core of the circulation.  Thunderstorms around the eye were generating strong upper level divergence which pumped out mass and allowed the surface pressure to decrease quickly.  The circulation of Tropical Cyclone Ernie is small and winds to tropical storm force extend out only about 90 miles (150 km) from the center of circulation.

Tropical Cyclone Ernie will remain in a very favorable environment for another 12 to 24 hours.  Ernie will be over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge southeast of Ernie is producing northerly winds near the tropical cyclone, but those winds are not creating significant wind shear.  Tropical Cyclone Ernie could strengthen further during the next day or so.  In a day or two Ernie will move into an environment of lower SSTs and more vertical wind shear.  Tropical Cyclone Ernie will weaken at that time.

A subtropical ridge southeast of Ernie is steering the tropical cyclone slowly toward the south-southwest.  The ridge is forecast to strengthen and extend westward.  When the ridge extends toward the west it will also steer Tropical Cyclone Ernie more toward the west.  On its anticipated track Tropical Cyclone Ernie poses no current threat to land.

Tropical Cyclone Ernie Forms Northwest of Australia

Tropical Cyclone Ernie formed northwest of Australia on Thursday.  At 2:00 p.m. EDT on Thursday the center of Tropical Cyclone Ernie was located at latitude 14.1°S and longitude 110.9°E which put it about 580 miles (940 km) north-northwest of Exmouth, Australia.  Ernie was moving toward the south-southwest at 5 m.p.h. (7 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (100 km/h).  The minimum surface pressure was 995 mb.

Thunderstorms developed around a small area of low pressure south of Indonesia during the past several days.  The storms consolidated near the center of circulation on Thursday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Ernie.  Ernie does have a well organized low level center of circulation, but many of the thunderstorms are occurring just to the west of the center of circulation.  There are also several bands of showers and thunderstorms in the southeastern quadrant of the circulation.  The thunderstorms near the center are generating upper level divergence which is pumping out mass to the south and southeast of Tropical Cyclone Ernie.

Tropical Cyclone Ernie is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge southeast of Ernie is generating northerly winds which are cause some vertical wind shear over the tropical cyclone.  However, the vertical wind shear is not strong enough to prevent further intensification of Tropical Cyclone Ernie.  Ernie should intensify during the next 24 hours and it could intensify rapidly during that time.  Tropical Cyclone Ernie will move into an unfavorable environment in a day or two.  Ernie will move over cooler SSTs and into a region where stronger upper level winds will produce more vertical wind shear.  The tropical cyclone will weaken at that time.

A subtropical ridge centered southeast of Ernie is steering the tropical cyclone slowly toward the south-southwest.  The ridge is forecast to strengthen and extend farther to the west.  When the ridge extends westward, it will steer Tropical Cyclone Ernie more toward the west.  On its anticipated track Tropical Cyclone Ernie currently poses no threat to land.