Category Archives: Australian Region

Tropical Cyclone Sean Weakens

Tropical Cyclone Sean weakened over the South Indian Ocean west of Australia on Tuesday.  At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Sean was located at latitude 26.7°S and longitude 107.3°E which put the center about 380 miles (610 km) west of Carnarvon, Australia.  Sean was moving toward the south-southwest at 16 m.p.h. (26 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 977 mb.

Tropical Cyclone Sean weakened on Tuesday as it moved over cooler water in the South Indian Ocean west of Australia.  An eye was no longer visible in the center of Sean’s circulation.  Thunderstorms were still occurring in bands in the southern and eastern parts of Tropical Cyclone Sean.  Bands in the northern and western parts of Sean’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Sean still produced some upper level divergence that pumped mass away to the southeast of the tropical cyclone.  The removal of mass in the upper levels of the atmosphere was less than the inflow of mass in the lower levels, which caused the surface pressure to increase.

The size of the circulation around Tropical Cyclone Sean increased even though Sean was weakening.  Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center of Tropical Cyclone Sean.

Tropical Cyclone Sean will move through an environment that will be unfavorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 24°C.  It will move under the eastern part of an upper level trough over the South Indian Ocean.  The upper level trough will produce northwesterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause moderate vertical wind shear.  The combination of cooler water and moderate vertical wind shear will cause Tropical Cyclone Sean to continue to weaken during the next 24 hours.

Tropical Cyclone Sean will move around the western part of a high pressure system over Australia.  The high pressure system will steer Sean toward the south during the next 24 hours. On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.

Tropical Cyclone Sean Rapidly Intensifies to Equivalent of Major Hurricane

Tropical Cyclone Sean rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean west of Australia on Monday.  At 10:00 a.m. EST on Monday the center of Tropical Cyclone Sean was located at latitude 23.0°S and longitude 110.4°E which put the center about 210 miles (340 km) west of Exmouth, Australia.  Sean was moving toward the southwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 936 mb.

A Warning was in effect for the portion of the coast from Onslow to Ningaloo.  The Warning included Exmouth.

Tropical Cyclone Sean rapidly intensified to the equivalent of a major hurricane west of Australia on Monday.  A small circular eye with a diameter of 10 miles (16 km) was at the center of Sean’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Sean.  Storms near the core of Sean generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Tropical Cyclone Sean was relatively small.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 110 miles (175 km) from the center of Tropical Cyclone Sean.

The Hurricane Intensity Index (HII) for Tropical Cyclone Sean was 25.1.  The Hurricane Size Index (HSI) was 12.6 and the Hurricane Wind Intensity Size Index (HWISI) was 37.7.  Tropical Cyclone Sean was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Tropical Cyclone Sean will move through an environment that will become unfavorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 27°C.  It will move under the eastern part of an upper level trough over the South Indian Ocean.  The upper level trough will produce northwesterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause the vertical wind shear to increase.  The combination of cooler water and  more vertical wind shear will cause Tropical Cyclone Sean to weaken during the next 24 hours.

Tropical Cyclone Sean will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Sean toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move a little farther away from the coast of Western Australia.

Bands in the eastern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause floods in some locations.  10.78 inches (274 mm) of rain has already fallen at the Karratha Airport.  4.37 inches (111 mm) of rain has already fallen at the Mardie Airport.

Flood Warnings were in effect for parts of the Pilbara and northern Gascoyne regions.  A Flood Warning was in effect for the Lyndon-Minilya Rivers. 

 

Tropical Cyclone Sean Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Sean intensified to the equivalent of a hurricane/typhoon near the coast of Western Australia on Sunday.  At 10:00 a.m. EST on Sunday the center of Tropical Cyclone Sean was located at latitude 20.5°S and longitude 113.9°E which put the center about 125 miles (200 km) north of Exmouth, Australia.   Sean was moving toward the west-southwest at 12 m.p.h. (19 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 978 mb.

A Warning was in effect for the portion of the coast from Whim Creek to Ningaloo.  The Warning included Karratha, Damoier, Onslow, and Exmouth.

Tropical Cyclone Sea intensified to the equivalent of a hurricane/typhoon near the coast of Western Australia on Sunday.  A circular eye with a diameter of 17 miles (28 km) formed at the center of Sean’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Sean.  Storms near the core of Sean generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Cyclone Sean was relatively small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Cyclone Sean.

Tropical Cyclone Sean will move through an environment favorable for intensification during the next 24 hours.  Sean 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 northwest of Australia.  The upper level ridge will produce easterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Cyclone Sean will intensify during the next 24 hours.

Tropical Cyclone Sean will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Sean toward the west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.  The center of Sean is forecast to remain over water.

Bands in the southern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause flash floods in some locations.  3.74 inches (95 mm) of rain fell at the Lombadina Airstrip.

A Flood Watch was in effect for the coastal parts of the Kimberley and the Pilbara Districts.  Catchments likely to be affected include the West Kimberley Rivers, the De Grey River, the Pilbara Coastal Rivers, the Fortescue River, the Onslow Coast, and the Lyndon-Minilya Rivers.

Tropical Cyclone Sean Strengthens Near Western Australia

Tropical Cyclone Sean strengthened near the coast of Western Australia on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Sean was located at latitude 19.7°S and longitude 115.7°E which put the center about 120 miles (195 km) northwest of Karratha, Australia.  Sean was moving toward the west-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 987 mb.

A Warning was in effect for the portion of the coast from Whim Creek to Ningaloo.  The Warning included Karratha, Damoier, Onslow, and Exmouth.

A former Tropical Low near the coast of Western Australia strengthened on Saturday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Sean.  The inner end of a rainband wrapped around the western side of the center of Tropical Cyclone Sean.  A circular eye appeared to be forming at the center of Sean’s circulation.  Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Sean.  Storms near the center of Sean generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass allowed the surface pressure to decrease.

The distribution of wind speeds around Tropical Cyclone Sean was relatively symmetrical.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Sean’s circulation.

Tropical Cyclone Sean will move through an environment favorable for intensification during the next 24 hours.  Sean 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 northwest of Australia. The upper level ridge will produce easterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Cyclone Sean will to intensify during the next 24 hours.  Sean could strengthen to the equivalent of a hurricane/typhoon.

Tropical Cyclone Sean will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Sean toward the west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.  The center of Sean is forecast to remain over water.

Bands in the southern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause flash floods in some locations.

Tropical Low Forms Near Western Australia

A Tropical Low formed near the coast of Western Australia on Friday.  At 4:00 p.m. EST on Friday the center of the Tropical Low was located at latitude 19.0°S and longitude 120.0°E which put the center about 100 miles (160 km) northeast of Port Hedland, Australia.  The tropical low was moving toward the west-southwest at 10 m.p.h. (16 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 995 mb.

A Warning was in effect for the portion of the coast from De Grey to Dampier.  The Warning included Port Hedland and Karratha.

A Watch was in effect for the portion of the coast from Ningaloo to Dampier.  The Watch included Onslow and Exmouth.

A low pressure system over the South Indian Ocean near the coast of Western Australia developed a well defined center of circulation and the Australian Bureau of Meteorology designated the system as a Tropical Low.  A ring of thunderstorms was forming around the center of the Tropical Low.  Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical low.  Bands of showers and thunderstorms were revolving around the center of circulation.

The Tropical Low will move through an environment favorable for the intensification of a tropical cyclone during the next 24 hours.  The Tropical Low will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge northwest of Australia.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  The only factor that will inhibit the intensification of the Tropical Low is the fact that the center of circulation is near the coast of Western Australia.  Much of the southern part of the Tropical Low is over land.  The Tropical Low is likely to intensify to a named tropical cyclone 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 west-southwest during the next 24 hours.  On its anticipated track, the Tropical Low will move parallel to the coast of Western Australia.  The center of the Tropical Low is forecast to remain over water.

The Tropical Low will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain is likely to cause flash floods in some locations.

Tropical Cyclone 05S Moves South of Cocos Islands

Tropical Cyclone 05S moved south of the Cocos Islands in the South Indian Ocean on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone 05S was located at latitude 14.2°S and longitude 96.6°E which put the center about 125 miles (200 km) south of the Cocos Islands.  Tropical Cyclone 05S was moving toward the south at 9 m.p.h. (15 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 1003 mb.

Tropical Cyclone 05S was moving under the western end of an upper level ridge that extended from Australia to the South Indian Ocean.  The upper level ridge was producing northeasterly winds that were blowing toward the top of the tropical cyclone.  Those winds were causing moderate vertical wind shear.  The wind shear caused the distribution of thunderstorms in Tropical Cyclone 05S to be asymmetrical.  Thunderstorms were occurring in bands in the western and southern parts of the tropical cyclone.  Bands in the northern and eastern parts of the circulation consisted primarily of showers and lower clouds.

The distribution of winds speeds around Tropical Cyclone 05S was also symmetrical. Winds to tropical storm force extended out 105 miles (165 km) in the southwestern quadrant of the tropical cyclone.  The winds in the other parts of Tropical Cyclone 05S were blowing at less than tropical storm force.

Tropical Cyclone 05S will move through an environment unfavorable for intensification during the next 24 hours.  The tropical cyclone will move over water where where the Sea Surface Temperatures are near 28°C.  It will continue to move under the western part of an upper level ridge that extends from Australia to the South Indian Ocean.  The upper level ridge will continue to produce northeasterly winds that will blow toward the top of Tropical Cyclone 05S.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification. Tropical Cyclone 05S is likely to start to weaken during the next 24 hours.

Tropical Cyclone 05S will move around the southwestern part of a high pressure system over Australia.  The high pressure system will steer the tropical cyclone toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone 05S will move farther away from the Cocos Islands on Saturday.

Tropical Cyclone 05S Forms West of Cocos Islands

Tropical Cyclone 05S formed over the South Indian Ocean west of the Cocos Islands on Thursday evening.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone 05S was located at latitude 12.1°S and longitude 95.2°E which put the center about 140 miles (225 km) east of the Cocos Islands.  Tropical Cyclone 05S was moving toward the east at 3 m.p.h. (5 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 1000 mb.

A low pressure system over the South Indian Ocean west of the Cocos Islands strengthened on Thursday evening and the U.S. Joint Typhoon Warning Center designated the system as Tropical Cyclone 05S.  The Australian Bureau of Meteorology designated the system as a Tropical Low.

The distribution of thunderstorms around Tropical Cyclone 05S was asymmetrical.  Thunderstorms were occurring in bands in the western half of the tropical cyclone.  Bands in the eastern side of Tropical Cyclone 05S consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence that pumped mass away to the west and south of the tropical cyclone.

The distribution of winds speeds around Tropical Cyclone 05S was also symmetrical.  Winds to tropical storm force extended out 105 miles (165 km) in the western half of the tropical cyclone.  The winds in the eastern side of Tropical Cyclone 05S were blowing at less than tropical storm force.

Tropical Cyclone 05S will move through an environment somewhat favorable for intensification during the next 24 hours.  The tropical cyclone will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the western part of an upper level ridge that extends from Australia to the South Indian Ocean.  The upper level ridge will produce northeasterly winds that will blow toward the top of Tropical Cyclone 05S.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification.  Tropical Cyclone 05S could intensify during the next 24 hours, if the upper level winds do not get any stronger.

Tropical Cyclone 05S will move around the southwestern part of a high pressure system over Australia.  The high pressure system will steer the tropical cyclone toward the southwest during the next 24 hours.  On its anticipated track, the center of Tropical Cyclone 05S will pass southwest of the Cocos Islands on Friday.

Tropical Cyclone Robyn Spins Southwest of Cocos Islands

Tropical Cyclone Robyn was spinning over the South Indian Ocean southwest of the Cocos Islands on Thursday.  At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Robyn was located at latitude 16.6°S and longitude 91.2°E which put the center about 485 miles (780 km) southwest of the Cocos Islands.  Robyn was moving toward the south-southeast at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 988 mb.

Tropical Cyclone Robyn strengthened on Thursday as it spun over the South Indian Ocean southwest of the Cocos Islands.  More thunderstorms formed near the center of Robyn’s circulation.  Thunderstorms were occurring in bands revolving around the center of Tropical Cyclone Robyn.  Storms near the center of Robyn generated upper level divergence that pumped mass away to the southeast of the tropical cyclone.

The distribution of winds speeds in Tropical Cyclone Robyn became more symmetrical on Thursday.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Robyn’s circulation.

Tropical Cyclone Robyn will move through an environment that will become unfavorable for intensification during the next 24 hours.  Robyn will move over water where where the Sea Surface Temperatures are near 26°C.  It will move under the western end of an upper level ridge that is west of Australia.  The upper level ridge will produce northerly winds that will blow toward the top of the tropical cyclone.  Those winds will cause moderate vertical wind shear. The combination of moderate vertical wind shear and marginal Sea Surface Temperatures is likely to cause Tropical Cyclone Robyn to weaken during the next 24 hours.

Tropical Cyclone Robyn will move around the southwestern end of a high pressure system that is west of Australia.  The high pressure system will steer Robyn toward the south-southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Robyn will move farther away from the Cocos Islands.

Tropical Cyclone 03S Forms West of Cocos Islands

Tropical Cyclone 03S formed over the South Indian Ocean west of the Cocos Islands on Wednesday.  At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone 03S was located at latitude 13.1°S and longitude 91.2°E which put the center about 385 miles (620 km) west of the Cocos Islands.  The tropical cyclone was moving toward the south-southwest at 9 m.p.h. (15 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 995 mb.

A low pressure system over the South Indian Ocean west of the Cocos Islands strengthened on Wednesday and the U.S. Joint Typhoon Warning Center designated the system as Tropical Cyclone 03S.  The distribution of thunderstorms in Tropical Cyclone 03S was asymmetrical.  Thunderstorms were occurring in bands in the western side of the tropical cyclone’s circulation.  Bands in the eastern side of the circulation consisted primarily of showers and lower clouds.  Storms west of the center of circulation generated upper level divergence that pumped mass away to the west of the tropical cyclone.

The distribution of wind speeds in Tropical Cyclone 03S was also asymmetrical.  Winds to tropical storm force extended out 140 miles (225 km) in the southern side of the tropical cyclone.  Winds to tropical storm force only extended out 70 miles (110 km) in the northern side of Tropical Cyclone 03S.

Tropical Cyclone 03S will move through an environment somewhat favorable for intensification during the next 24 hours.  The tropical cyclone will move over water where where the Sea Surface Temperatures are near 27°C.  It will move under the western end of an upper level ridge that is west of Australia.  The upper level ridge will produce northerly winds that will blow toward the top of the tropical cyclone.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification.  Tropical Cyclone 03S could strengthen during the next 24 hours if the upper level winds do not get any stronger.

Tropical Cyclone 03S will move around the western end of a high pressure system that is west of Australia.  The high pressure system will steer the tropical cyclone toward the south-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone 03S will move farther away from the Cocos Islands.

Tropical Cyclone Paul Weakens

Tropical Cyclone Paul weakened over the Coral Sea on Thursday night. At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Paul was located at latitude 15.2°S and longitude 156.5°E which put it about 325 miles (525 km) southeast of the Tagula Island. Paul was moving toward the east at 4 m.p.h. (6 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 1001 mb.

Tropical Cyclone Paul strengthened earlier on Thursday when it was in a more favorable environment. Then an upper level trough near the east coast of Australia began to produce strong west-northwesterly winds that blew across the top of Paul’s circulation. Those winds caused the vertical wind shear to increase. The stronger vertical wind shear blew the tops off of many of the thunderstorms in Tropical Cyclone Paul. A few thunderstorms were still occurring in bands in the southeastern part of Paul’s circulation. Bands in the other parts of Tropical Cyclone Paul consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 40 miles (65 km) from the center of Paul.

Tropical Cyclone Paul will move through an environment unfavorable for intensification during the next 24 hours. Paul will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level trough near eastern Australia will continue to produce strong west-northwesterly winds that will blow across the top of Paul’s circulation. Those winds will cause strong vertical wind shear. The strong wind shear will cause Paul to continue to weaken.

Tropical Cyclone Paul will be steered by the winds in the lower levels of the atmosphere because of the strong vertical wind shear. Paul will move around the northern side of high pressure system over the Southwest Pacific Ocean and eastern Australia. The high pressure system will steer Paul toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Cyclone Paul will weaken over the Coral Sea.