Category Archives: Indian Ocean

Tropical Cyclone Errol Makes Landfall in Western Australia

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Tropical Cyclone Errol made landfall on the coast of Western Australia on Friday.  At 5:00 a.m. EDT on Friday the center of Tropical Cyclone Errol was located at latitude 16.1°S and longitude 124.3°E which put the center about 20 miles (35 km) south-southwest of Kuri Bay, Australia.  Errol was moving toward the east at 6 m.p.h. (10 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. (105 km/h).  The minimum surface pressure was 998 mb.

Tropical Cyclone Errol made landfall on the coast of Western Australia south-southwest of Kuri Bay on Friday.  Errol was weakening at the time of landfall.  Tropical Cyclone Errol was the equivalent of a tropical storm when it made landfall.  The circulation around Errol was small.  Winds to tropical storm force extended out 70 miles (110 km) from the center of Tropical Cyclone Errol.

An upper level trough near the coast of Western Australia will steer Tropical Cyclone Errol toward the east-southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Errol will move inland over Western Australia.  The center of Errol’s circulation will move southeast of Kuri Bay.

Tropical Cyclone Errol will bring gusty winds and locally heavy rain to parts of Western Australia south of Kuri Bay.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Errol Weakens Rapidly

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Tropical Cyclone Errol weakened rapidly as it approached the coast of Western Australia on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Cyclone Errol was located at latitude 16.2°S and longitude 122.1°E which put the center about 135 miles (220 km) north-northwest of Broome, Australia.  Errol was moving toward the east-southeast at 14 m.p.h. (22 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 980 mb.

A Warning is in effect for the coast of Western Australia from Kuri Bay to Broome.  The Warning includes Derby.

Tropical Cyclone Errol weakened rapidly as it approached the coast of Western Australia on Thursday.  An upper level trough near the coast of Western Australia was producing strong northwesterly winds that were blowing the top of Errol’s circulation.  Those winds were causing strong vertical wind shear.  The strong vertical wind shear was causing Tropical Cyclone Errol to weaken rapidly.

The strong vertical wind shear was also affecting the structure of Tropical Cyclone Errol.  Thunderstorms were still occurring in bands in the eastern side of Errol’s circulation.  Bands in the western side of Tropical Cyclone Errol consisted primarily of showers and lower clouds.

The circulation around Tropical Cyclone Errol was small.  Winds to hurricane/typhoon force extended out 15 miles (25 km) in the eastern side of Errol’s circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Tropical Cyclone Errol.

Tropical Cyclone Errol will move through an environment unfavorable for intensification during the next 12 hours. Errol will move over water where where the Sea Surface Temperatures are near 30°C.  However, the upper level trough near the coast of western Australia will continue to produce strong northwesterly winds that will blow toward the of Errol’s circulation.  Those winds will continue to cause strong vertical wind shear.  The strong vertical wind shear will cause Tropical Cyclone Errol to continue to weaken rapidly.

The upper level trough near the coast of Western Australia will steer Tropical Cyclone Errol toward the east-southeast during the next 24 hours.  On its anticipated track, the center of Tropical Cyclone Errol will make landfall near Cape Leveque in about 12 hours.  The center of Errol’s circulation will pass north of Derby.

Tropical Cyclone Errol will bring strong winds and locally heavy rain to the part of Western Australia near Cape Leveque and northeast of Derby.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Errol Rapidly Intensifies to Equivalent of Cat. 5 Hurricane

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Tropical Cyclone Errol rapidly intensified to the equivalent of a Category 5 hurricane over the South Indian Ocean northwest of Australia on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Cyclone Errol was located at latitude 14.2°S and longitude 118.9°E which put the center about 325 miles (520 km) northwest of Broome, Australia.  Errol was moving toward the southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).   The minimum surface pressure was 919 mb.

A Watch is in effect for the coast of Western Australia from Kuri Bay to Broome.  The Watch includes Derby.

Tropical Cyclone Errol rapidly intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Wednesday.  A very small circular eye with a diameter of 10 miles (16 km) was at the center of Errol’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 Errol.  Storms near the core of Errol generated 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 size of the circulation around Tropical Cyclone Errol increased while Errol rapidly intensified.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Errol’s circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Tropical Cyclone Errol.

The Hurricane Intensity Index (HII) for Tropical Cyclone Errol is 35.0.  The Hurricane Size index (HSI) is 12.8 and the Hurricane Wind Intensity Size Index (HWISI) is 47.8.  Tropical Cyclone Errol is similar in size and intensity to Hurricane Michael when Michael hit Northwest Florida in 2018.

Tropical Cyclone Errol will move through an environment favorable for a powerful tropical cyclone during the next 24 hours.  Errol will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over Australia and the South Indian Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Errol could continue to intensify during the next 24 hours unless an eyewall replacement cycle occurs.  If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could cause Errol to weaken.  An upper level trough over the South Indian Ocean will approach Tropical Cyclone Errol on Thursday.  The upper level trough will cause the vertical wind shear to increase.  More vertical wind shear will cause Errol to weaken.

Tropical Cyclone Errol will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Errol toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Errol will remain north of Western Australia during the next day or so.  The upper level trough over the South Indian Ocean will cause Errol to start to move back toward the southeast on Thursday.

Tropical Cyclone Errol Rapidly Intensifies to Equivalent of a Major Hurricane

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Tropical Cyclone Errol rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean northwest of Australia during Tuesday night.  At 5:00 a.m. EDT on Wednesday the center of Tropical Cyclone Errol was located at latitude 14.2°S and longitude 119.1°E which put the center about 325 miles (520 km) northwest of Broome, Australia. Errol was moving toward the west-southwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 940 mb.

A Watch is in effect for the coast of Western Australia from Kuri Bay to Broome.  The Watch includes Derby.

Tropical Cyclone Errol rapidly intensified to the equivalent of a  major hurricane during Tuesday night.  A very small circular eye with a diameter of 8 miles (13 km) was at the center of Errol’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 Errol.  Storms near the core of Errol 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 Errol was small.  Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Errol’s circulation.  Winds to tropical storm force extended out 75 miles (120 km) from the center of Tropical Cyclone Errol.

The Hurricane Intensity Index (HII) for Tropical Cyclone Errol is 28.3.  The Hurricane Size index (HSI) is 7.2 and the Hurricane Wind Intensity Size Index (HWISI) is 35.5  Tropical Cyclone Errol is similar in size and intensity to Hurricane Charley when Charley hit Southwest Florida in 2004.

Tropical Cyclone Errol will move through an environment favorable for intensification during the next 24 hours.  Errol will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over Australia and the South Indian Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Errol could continue to intensify during the next 24 hours unless an eyewall replacement cycle occurs.  If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could cause Errol to weaken.

Tropical Cyclone Errol will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Errol toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Errol will remain north of Western Australia during the next day or so.  Errol could start to move back toward the southeast on Thursday.

Tropical Cyclone Errol Rapidly Intensifies to Equivalent of Hurricane/Typhoon

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Tropical Cyclone Errol rapidly intensified to the equivalent of a hurricane/typhoon over the South Indian Ocean northwest of Australia on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Cyclone Errol was located at latitude 14.2°S and longitude 119.5°E which put the center about 310 miles (500 km) north-northwest of Broome, Australia.  Errol was moving toward the west-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 976 mb.

Tropical Cyclone Errol rapidly intensified to the equivalent of a hurricane/typhoon on Tuesday.  The inner end of a rainband wrapped around the center of Errol’s circulation.  A very small circular eye formed at the center of Tropical Cyclone Errol.  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 Errol’s circulation.  Storms near the core of Errol 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 Errol was small.  Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Errol’s circulation.  Winds to tropical storm force extended out 85 miles (135 km) from the center of Tropical Cyclone Errol.

Tropical Cyclone Errol will move through an environment very favorable for intensification during the next 24 hours.  Errol will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over Australia and the South Indian Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Errol will intensify during the next 24 hours.  Errol is likely to rapidly intensify to the equivalent of a  major hurricane..

Tropical Cyclone Errol will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Errol toward the west-southwest during the next 24 hours. On its anticipated track, Tropical Cyclone Errol will remain north of Western Australia during the next day or so. Errol could move back toward the southeast later this week.

Tropical Cyclone Errol Intensifies Northwest of Australia

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Tropical Cyclone Errol intensified over the South Indian Ocean northwest of Australia on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Errol was located at latitude 13.9°S and longitude 120.5°E which put the center about 290 miles (470 km) north-northwest of Broome, Australia.  Errol was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 992 mb.

A former Tropical Low over the South Indian Ocean northwest of Australia started to intensify on Tuesday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Errol.

The circulation around Tropical Cyclone Errol exhibited much more organization on Tuesday.  The inner end of a rainband wrapped around the southern and western sides of the center of Errol’s circulation.  The strongest winds were occurring in the inner part of that rainband.  Other bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Errol.  Storms near the center of Errol’s circulation 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 Errol was small.  Winds to tropical storm force extended out 70 miles (110 km) from the center of Errol’s circulation.

Tropical Cyclone Errol will move through an environment somewhat favorable for intensification during the next 24 hours.  Errol will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over Australia and the South Indian Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Errol will intensify during the next 24 hours.  Errol could intensify rapidly at times.  Tropical Cyclone Errol will strengthen to the equivalent of a hurricane/typhoon.  Errol could intensify to the equivalent of a major hurricane on Wednesday.

Tropical Cyclone Errol 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 during the next 24 hours.  On its anticipated track, Tropical Cyclone Errol will remain north of Western Australia during the next day or so.  Errol could move back toward the southeast later this week.

Tropical Low Causes Warning for Western Australia

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The risk posed by a Tropical Low caused the Australia Bureau of Meteorology to issue a Warning for a portion of the coast of Western Australia on Saturday.  At 5:00 p.m. EDT on Saturday the center of the Tropical Low was located at latitude 12.2°S and longitude 125.8°E which put the center about 260 miles (420 km) north-northeast of Kuri Bay, Australia.  The Tropical Low was moving toward the southwest 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 1003 mb.

A Warning is in effect for the portion of the coast of Western Australia from Kalumburu to Kuri Bay.

A Watch is in effect for the portion of the coast of Western Australia from Kuri Bay to Cockatoo Island.

The U.S. Joint Typhoon Warning Center designated the Tropical Low as Tropical Cyclone 29S.

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

The asymmetric distribution of thunderstorms was also causing the pattern of wind speeds to be asymmetrical.  Winds to tropical storm force extended out 115 miles (185 km) in the southern side of the Tropical Low.  The winds in the northern part of the Tropical Low were blowing at less than tropical storm force.

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

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

The Tropical Low could bring gusty winds and locally heavy rain to the coast of Western Australia between Kalumburu and Kuri Bay.  Heavy rain could cause flash floods in some locations.

Tropical Low Prompts Watch for Western Australia

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The risk posed by a Tropical Low over the Timor Sea caused the Australian Bureau of Meteorology to issue a Watch for a portion of the coast of Western Australia on Friday.  At 11:00 a.m. EDT on Friday the center of the Tropical Low was located at latitude 9.8°S and longitude 129.1°E which put the center about 215 miles (350 km) northwest of Darwin, Australia.  The Tropical Low was moving toward the south-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

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

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

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

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

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

 

Tropical Cyclone Forming Over Timor Sea

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A tropical cyclone was forming over the Timor Sea on Thursday morning.  A low pressure system was gradually organizing into a tropical cyclone over the Timor Sea north of Darwin, Australia on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of the low pressure system was located at latitude 8.7°S and longitude 130.3°E which put the center about 270 miles (435 km) north of Darwin, Australia.  The low pressure system was moving toward the southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1001 mb.

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

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

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

Courtney Begins Transition to Extratropical Cyclone

Tropical Cyclone Courtney began a transition to an extratropical cyclone over the South Indian ocean on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Cyclone Courtney was located at latitude 25.0°S and longitude 88.7°E which put the center about 1020 miles (1645 km) south-southwest of the Cocos Islands.  Courtney was moving toward the south at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 986 mb.

Tropical Cyclone Courtney began a transition to an extratropical cyclone over the South Indian Ocean south-southwest of the Cocos Islands on Monday.  An upper level trough was producing strong northwesterly winds that were blowing across the top of Courtney’s circulation.  Those winds were causing strong vertical wind shear.  The strong wind shear blew off the tops of many of the thunderstorms in Tropical Cyclone Courtney.  A few thunderstorms were still occurring in a bands in the southeastern periphery of Courtney’s circulation.  Bands in the other parts of Tropical Cyclone Courtney consisted primarily of showers and lower clouds.

The lack of thunderstorms in much of Tropical Cyclone Courtney caused the distribution of winds speeds to become asymmetrical.  Winds to tropical storm force extended out 165 miles (265 km) in the southern half of Courtney’s circulation.  Winds to tropical storm force only extended out 85 miles (135 km) in the northern half of Tropical Cyclone Courtney.

Tropical Cyclone Courtney will move through an environment that will be unfavorable for intensification of a tropical cyclone during the next 24 hours.  Courtney will move over water where where the Sea Surface Temperatures are near 24°C.  It will move under the eastern side of an upper level trough over the South Indian Ocean.  The upper level trough will produce  strong northwesterly winds that will blow toward the top of Courtney’s circulation.  Those winds will cause strong vertical wind shear to continue.  The combination of colder Sea Surface Temperatures and strong vertical wind shear will cause Tropical Cyclone Courtney to continue to make a transition to an extratropical cyclone during the next 24 hours.

Since much of the circulation of Tropical Cyclone Courtney only exists in the the lower levels of the atmosphere, Courtney will be steered by the winds at those levels.  Courtney will move around the northern side of a high pressure system over the South Indian Ocean.  The high pressure system will steer Courtney toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Courtney will move farther away from the Cocos Islands.