Monthly Archives: April 2025

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 Cyclone Tam Develops East of New Caledonia

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Tropical Cyclone Tam developed over the South Pacific Ocean east of New Caledonia on Tuesday.  At 5:00 a.m. EDT on Tuesday the center of Tropical Cyclone Tam was located at latitude 21.9°S and longitude 171.4°E which put the center about 335 miles (540 km) east of Noumea, New Caledonia.  Tam was moving toward the southeast at 25 m.p.h. (40 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 988 mb.

A low pressure system over the South Pacific Ocean east of New Caledonia strengthened during Monday night and the Fiji Meteorological Service designated the system as Tropical Cyclone Tam.

The distribution of thunderstorms around Tropical Cyclone Tam was asymmetrical.  Tam was located under the eastern side of an upper level trough that was east of Australia.  The upper level trough was producing strong northwesterly winds that were blowing toward the top of Tam’s circulation.  Those winds were causing strong vertical wind shear.  The strong wind shear was causing the asymmetrical distribution of thunderstorms in Tropical Cyclone Tam.  Thunderstorms were occurring in bands in the southern and eastern parts of Tam’s circulation.  Bands in the northern and western parts of Tropical Cyclone Tam consisted primarily of showers and lower clouds.

The asymmetrical distribution of thunderstorms was also causing the distribution of wind speeds to be asymmetrical.  Winds to tropical storm force extended out 250 miles (400 km) in the eastern side of Tropical Cyclone Tam.  The winds in the western half of Tam’s circulation were blowing at less than tropical storm force.

Tropical Cyclone Tam will move into an environment that will be unfavorable for the intensification of a tropical cyclone during the next 24 hours.  Tam will move over water where where the Sea Surface Temperatures are near 24°C.  The upper level trough east of Australia will continue to cause strong vertical wind shear.  The combination of cool Sea Surface Temperatures and strong vertical wind shear will cause Tropical Cyclone Tam to make a transition to a strong extratropical cyclone during the next 24 hours.

The upper level trough east of Australia will steer Tropical Cyclone Tam toward the south during the next 24 hours.  On its anticipated track, Tam will move quickly away from New Caledonia.  Tropical Cyclone Tam will move closer to northern New Zealand.

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.