Category Archives: Australian Region

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.

Powerful Tropical Cyclone Debbie Makes Landfall in Queensland

Powerful Tropical Cyclone Debbie made landfall in Queensland on Monday night.  At 9:00 p.m. EDT on Monday the center of Tropical Cyclone Debbie was located at latitude 20.2°S and longitude 148.7°E which put it about 30 miles (50 km) east-southeast of Bowen, Australia.  Debbie was moving toward the southwest at 7 m.p.h. (12 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 943 mb.

Tropical Cyclone Debbie intensified rapidly on Monday into the equivalent of a major hurricane.  A symmetrical eye developed at the center of circulation and a ring of strong thunderstorms surrounded the eye.  Bands of thunderstorms were revolving around the core of Tropical Cyclone Debbie.  Winds to hurricane force extend out about 40 miles (65 km) from the center.  Winds to tropical storm force extended out about 140 miles (225 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Debbie was 20.6.  The Hurricane Size Index (HSI) was 16.0 and the Hurricane Wind Intensity Size Index (HWISI) was 36.6.  These indices indicate that Tropical Cyclone Debbie was capable of causing regional major damage.

The center of Tropical Cyclone Debbie made landfall on the coast of Queensland between Bowen and Proserpine.  Debbie will bring strong gusty winds to the portions of Queensland in the path of the tropical cyclone.  Tropical Cyclone Debbie will cause a storm surge along the coast near and to the south of where the center makes landfall.  Debbie will also produce heavy rain as it moves inland and flooding could occur in some areas.

Tropical Cyclone Debbie will weaken after the center moves inland.  The core of Debbie will move across the Clarke Range and those mountains will speed the dissipation of the tropical cyclone.

Strengthening Tropical Cyclone Debbie Nears Queensland

Tropical Cyclone Debbie strengthened on Sunday as it moved nearer to the coast of Queensland.  At 8:00 p.m. EDT on Sunday the center of Tropical Cyclone Debbie was located at latitude 19.1°S and longitude 150.4°E which put it about 155 miles (250 km) east-northeast of Bowen, Australia.  Debbie was moving toward the south-southwest at 5 m.p.h. (7 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 972 mb.

The primary rainband finally wrapped entirely around the center of circulation of Tropical Cyclone Debbie on Sunday and an eye formed.  The eye has a diameter of 35 miles (55 km).  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that eyewall.  Additional bands of showers and thunderstorms are revolving around the core of the circulation.  The circulation is symmetrical and well organized.  Thunderstorms around the core of the circulation are producing upper level divergence which is pumping out mass in all directions and the pressure is decreasing.

Tropical Cyclone Debbie will be moving through an environment favorable for intensification until it makes landfall in Australia.  Debbie will move over water where the Sea Surface Temperature is near 29°C.  The winds in the upper levels are weak and there is little vertical wind shear.  Tropical Cyclone Debbie will intensify until it makes landfall.  Since an eye has formed, Tropical Cyclone Debbie could intensify rapidly on Monday.

Tropical Cyclone Debbie is moving around a ridge over Australia.  The ridge steered Debbie toward the south-southwest on Sunday.  Debbie is expected to start to moving more toward the west-southwest on Monday.  On its anticipated track Tropical Cyclone Debbie could reach the coast of Queensland within 24 hours.  The landfall will likely occur between Ayr and Mackay with the highest probability of a landfall near Bowen.

The Hurricane Intensity Index (HII) for Tropical Cyclone Debbie is 11.5.  The Hurricane Size Index (HSI) is 18.3 and the Hurricane Wind Intensity Size Index (HWISI) is 29.8.  Those indices will increase as Tropical Cyclone Debbie strengthens on Monday.  Tropical Cyclone Debbie will bring strong winds, storm surge and locally heavy rainfall to coastal regions of Queensland.

Tropical Cyclone Debbie Moves Toward Queensland and Strengthens

Tropical Cyclone Debbie moved toward Queensland and strengthened on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Debbie was located at latitude 18.2°S and longitude 151.2°E which put it about 295 miles (475 km) east-northeast of Townsville, Australia.  Debbie was moving toward the west-southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 982 mb.

The circulation of Tropical Cyclone Debbie continued to become better organized on Saturday.  A primary rainband wrapped around the southern and western sides of the center of circulation.  An eyewall appeared to be forming but there were breaks on the east side of the incipient eyewall.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  The thunderstorms were generating upper level divergence which was pumping mass out in all directions.  The circulation is very symmetrical and winds to tropical storm force extend out about 190 miles (305 km) from the center.

Tropical Cyclone Debbie will be moving through an environment that is very favorable for intensification during the next 24 hours.  Debbie will move moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Debbie will continue to intensify and it could intensify rapidly once a complete eyewall surrounds the center of circulation.  Tropical Cyclone Debbie will become the equivalent of a hurricane/typhoon on Sunday and it could strengthen into the equivalent of a major hurricane before it reaches the coast of Queensland.

Tropical Cyclone Debbie is moving around the eastern end of a ridge centered over northern Australia.  The ridge is steering Debbie toward the west-southwest and that general motion is expected to continue during the next several days.  On its anticipated track the center of Tropical Cyclone Debbie could approach the coast of Queensland in 36 hours.  Tropical Cyclone Debbie could make landfall between Mackay and Rollingstone.  The greatest probability currently is for a landfall between Bowen and Townsville near Ayr.

Tropical Cyclone Debbie will bring destructive winds, storm surge and heavy rain to the coast of Queensland in about 36 hours.

Tropical Cyclone Debbie Develops East of Queensland

The low level circulation of a tropical low east of Queensland continued to organize on Friday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Debbie early on Saturday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Debbie was located at latitude 17.4°S and longitude 151.9°E which put it about 360 miles (580 km) east-northeast of Townsville, Australia.  Debbie was moving toward the southwest at 6 m.p.h. (9 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 992 mb.

The low level circulation of Tropical Cyclone Debbie continued to consolidate around the center of circulation on Friday.  Numerous bands of thunderstorms were revolving around the center of circulation and an eye-like feature appeared on satellite imagery at various times.  The structure of the circulation was fairly symmetrical, although there were more bands of showers and thunderstorms in the eastern half of Debbie.  Thunderstorms near the core of the circulation were generating upper level divergence, which was pumping out mass in all directions.

Tropical Cyclone Debbie is moving through an environment that is very favorable for intensification.  Debbie is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are very weak and there is almost no vertical wind shear.  Tropical Cyclone Debbie should continue to intensify and it could intensify very rapidly once a well developed inner core forms around an eye.  Tropical Cyclone Debbie could strengthen into the equivalent of a major hurricane in two or three days.

A subtropical ridge over northern Australia is steering Tropical Cyclone Debbie toward the southwest and a general southwesterly or west-southwesterly motion is expected to continue for the next two or three days.  On its anticipated track Tropical Cyclone Debbie could approach the coast of Queensland near Townsville in about 72 hours.  Debbie could be the equivalent of a major hurricane when it approaches the coast.