Tag Archives: Australia

Tropical Cyclone Ernie Very Rapidly Intensifies Into Equivalent of a Major Hurricane

Tropical Cyclone Ernie intensified very rapidly into the equivalent of a major hurricane during the past few hours.  Ernie strengthened from a tropical low to the equivalent of a major hurricane in one day which is an extremely rapid rate of intensification.  At 8:00 a.m. EDT on Friday the center of Tropical Cyclone Ernie was located at latitude 15.5°S and longitude 110.2°E which put it about 485 miles (780 km) north-northwest of Exmouth, Australia.  Ernie was moving toward the south at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 175 m.p.h. (290 km/h).  The minimum surface pressure was 936 mb.

Tropical Cyclone Ernie is a very small well organized storm.  It has a small eye surrounded by a ring of very strong thunderstorms.  The strongest winds are occurring in the ring of storms around the eye.  Additional bands of thunderstorms are revolving around the core of Ernie.  The thunderstorms in the core of Tropical Cyclone Ernie are generating strong upper level divergence which is pumping out mass and caused the surface pressure to decrease very rapidly.  Winds to hurricane/typhoon force extend out about 18 miles (30 km) from the center of circulation.  Winds to tropical storm force extend out about 90 miles (150 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Ernie is 23.6.  The Hurricane Size Index (HSI) is 7.8 and the Hurricane Wind Intensity Size Index (HWISI) is 31.4.  Those indices indicate that Tropical Cyclone Ernie is capable of causing localized significant damage.

Tropical Cyclone Ernie is in an environment favorable for tropical cyclones.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge centered southeast of Ernie is producing northerly winds which are blowing toward the tropical cyclone but the vertical wind shear is currently having no effect on it.  Tropical Cyclone Ernie could intensify more during the next 12 hours.  Ernie will move into an area of cooler SSTs and stronger vertical winds in a day or so.  The less favorable environment will cause Tropical Cyclone Ernie to weaken.  Tropical Cyclone Ernie could weaken quickly because of its small size, if the vertical wind shear increases rapidly.

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

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.

Tropical Cyclone Caleb Forms Over South Indian Ocean

Tropical Cyclone Caleb formed over the South Indian Ocean on Thursday.  At 8:00 a.m. EDT on Thursday the center of Tropical Cyclone Caleb was located at latitude 13.0°S and longitude 100.7°E which put it about 255 miles (410 km) east-southeast of Cocos Island.  Caleb was moving toward the south-southeast 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 995 mb.

Although there is a well defined low level circulation in Tropical Cyclone Caleb, the distribution of thunderstorms is asymmetrical.  The strongest thunderstorms are occurring in the northwestern quadrant of the circulation and they are in the primary rainband.  Those thunderstorms contain the strongest winds.  There are few thunderstorms in the other parts of the circulation, although there are some bands of lower clouds and showers in those regions.  The thunderstorms in the primary rainband are generating upper level divergence which is pumping out mass to the west of Tropical Cyclone Caleb.

Tropical Cyclone Caleb is in an environment that is marginal for intensification.  Caleb is moving over water where the Sea Surface Temperature is near 28°C.  So, there is enough energy in the upper ocean to support intensification.  However, an upper level ridge located southeast of Caleb is producing easterly winds which are blowing across the top of the tropical cyclone.  The easterly winds are generating moderate vertical wind shear and the shear is probably the reason why most of the thunderstorms are occurring in the northwestern quadrant of the circulation.  The moderate shear will inhibit intensification, but some strengthening may be possible if the upper level winds abate.

A ridge to the east of Caleb is steering the tropical cyclone toward the south-southeast and that general motion is expected to continue for another day or two.  Eventually, a second ridge is forecast to strengthen and steer Tropical Caleb back toward the northwest.

Tropical Cyclone 03S Moving West of Australia

A tropical cyclone designated 03S moved farther west of Australia and weakened on Saturday.  Tropical Cyclone 03S moved across northern Australia as a low pressure system last week before move off the coast near Broome.  After the center of the low moved over the South Indian Ocean thunderstorms developed near the core of the system and the Australian Bureau of Meteorology classified it as a tropical low.  The tropical low strengthened into the equivalent of a tropical storm on Friday night, but the Australian Bureau of Meteorology did not give the system a name.

At 7:00 p.m. EST on Saturday the center of Tropical Cyclone 03S was located at latitude 19.5°S and longitude 109.8°E which put it about 335 miles (540 km) northwest of Learmonth, Australia.  Tropical Cyclone 03S was moving toward the west at 12 m.p.h. (19 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 994 mb.

Tropical Cyclone 03S has a well defined low level circulation but the distribution of thunderstorms is asymmetrical.  Most of the stronger thunderstorms are forming in bands west of the center of circulation.  There are also bands in the eastern half of the circulation but they consist primarily of low clouds and rain showers.  Strong easterly winds in the upper levels are shearing the tops off of any thunderstorms that develop in the eastern part of the circulation.  The easterly winds are also inhibiting upper level divergence to the east of the center.

Tropical Cyclone 03S will move into an environment that will be unfavorable for intensification.  Tropical Cyclone 03S is moving over water where the Sea Surface Temperature is near 26°C, but it will move over cooler water during the next several days.  An upper level ridge centered over Australia is generating easterly winds which are blowing across the top of the tropical cyclone.  The easterly winds are causing moderate vertical wind shear and are responsible for the asymmetrical distribution of thunderstorms.  Tropical Cyclone 03S is likely to weaken slowly during the next several days.

A subtropical ridge will continue to steer Tropical Cyclone 03S to the west during the next few days.  On its anticipated track Tropical Cyclone 03S is expected to move farther away from Western Australia as it weakens.

Tropical Low Forms Over Western Australia

An area of low pressure system has been moving across northern Australia during the past few days.  The low remains organized and the Australian Bureau of Meteorology classified the system as a Tropical Low on Wednesday because of the potential for it to develop into a tropical cyclone.  At 10:00 a.m. EST on Wednesday the center of the Tropical Low was located at latitude 15.9°S and longitude 127.0°E which put it about 80 miles (130 km) west-southwest of Wyndham, Australia.  The Tropical Low was moving toward the west at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) an there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1002 mb.

There is a well defined cyclonic circulation in the lower levels of the atmosphere, but there are not many thunderstorms in the core of that circulation.  Most of the thunderstorms are developing in bands that are on the periphery of the circulation.  The strongest thunderstorms are forming in bands in the western portion of the circulation as that part of the Tropical Low begins to moves over water.  The strongest winds are also occurring in these thunderstorms that are over water.  The Tropical Low is moving underneath an upper level ridge and the ridge is causing upper level divergence which is pumping out mass.

The core of the Tropical Low is still over Western Australia and moving over land is the primary factor inhibiting intensification of the system.  The atmospheric environment is favorable for intensification.  The upper level ridge is producing light winds over the Tropical Low and there is little vertical wind shear.  The Sea Surface Temperature of the water west of Australia is near 30°C and there will be plenty of energy in the ocean to support strengthening when the core of the circulation moves west of Australia.  Some slow organization of the circulation is possible during the next 12 hours as the core of the Tropical Low moves closer to the coast of Western Australia.  Further intensification is likely during the next several days once the core of the Tropical Low moves over the warm water.  The Tropical Low could strengthen into the first named tropical cyclone of 2017 later this week.

The upper level ridge is producing light easterly winds which are slowly steering the Tropical Low toward the west.  That general motion is expected to continue for another day or so.  Eventually, the Tropical Low is forecast to move on a west-southwesterly track that would paralle, but keep it to the west of the coast of Western Australia during the next several days.