Tag Archives: Broome

Tropical Cyclone Errol Weakens Rapidly

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

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

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

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

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 Strengthens to Tropical Cyclone Zelia

A former Tropical Low near the coast of Western Australia strengthened to Tropical Cyclone Zelia on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Zelia was located at latitude 18.7°S and longitude 118.9°E which put the center about 110 miles (175 km) north of Port Hedland, Australia.  Zelia was moving toward the south-southwest at 7 m.p.h. (11 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 991 mb.

A former Tropical Low near the coast of Western Australia strengthened on Tuesday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Zelia.  More thunderstorms formed near the center of Zelia’s circulation.  Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Zelia.  Storms near the center of Zelia 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 Zelia became more symmetrical on Tuesday.  Winds to tropical storm force extended out 145 miles (230 km) from the center of Zelia’s circulation.

A weather station on Rowley Shoals measured a sustained wind speed of 47 kt (54 m.p.h. or 87 km/h) and a wind gust of 64 kt (74 m.p.h. or 119 km/h).

Tropical Cyclone Zelia will move through an environment favorable for intensification during the next 24 hours.  Zelia will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the middle part of an upper level ridge that extends from Australia to the South Indian Ocean.  The upper level winds are weak near the middle of the middle of the ridge and there will be little vertical wind shear.  Tropical Cyclone Zelia will intensify during the next 24 hours.  Zelia is likely to strengthen to the equivalent of a hurricane/typhoon.

Tropical Cyclone Zelia will move around the western side of a high pressure system over Australia.  The high pressure system will steer Zelia slowly toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone will move closer to the coast of Western Australia.  Zelia could approach the coast between Wallal Downs and Port Hedland in 48 hours.

Tropical Cyclone Zelia will bring strong winds and heavy rain to parts of Western Australia.

A Warning is in effect for the portion of the coast from Broome to Port Hedland.  The Warning includes Wallal Downs and De Grey.

A Watch is in effect for the portion of the coast from Port Hedland to Dampier.  The Watch extends inland to Marble Bar.

Heavy rain is likely to cause floods in some locations.

Flood Watches are in effect for the De Grey River, the Pilbara coastal Rivers, the Fortescue River and parts of the Sandy Desert.

Elsewhere over the South Indian Ocean, Tropical Cyclone Vince continued to move farther away from Rodrigues and Tropical Cyclone Taliah continued to move farther away from the Cocos Islands.

At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Vince was located at latitude 29.5°S and longitude 70.3°E which put the center about 805 miles (1295 km) south-southeast of Port Mathurin, Rodrigues.  Vince was moving toward the south-southeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). vThe minimum surface pressure was 971 mb.

At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Taliah was located at latitude 16.4°S and longitude 91.5°E which put the center about 435 miles (705 km) southwest of the Cocos Islands.  Taliah was moving toward the south-southwest at 8 m.p.h. (13 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 982 mb.

Tropical Low Develops Near Western Australia

A Tropical Low developed near the coast of Western Australia on Monday.  At 4:00 p.m. EST on Monday the center of the Tropical Low was located at latitude 15.7°S and longitude 120.9°E which put the center about 180 miles (290 km) north-northwest of Broome, Australia.  The Tropical Low was moving toward the southwest at 6 m.p.h. (10 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 997 mb.

The circulation around a Tropical Low near the coast of Western Australia exhibited more organization on Monday.  Thunderstorms organized in bands in the southern and western parts of the Tropical Low.  Bands in the northern and eastern parts of the circulation still consisted primarily of showers and lower clouds.  Storms near the center of circulation began to generate upper level divergence that started to pump mass away from the Tropical Low.

The Tropical Low will move through an environment 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.  It will move under the northern part of an upper level ridge over Australia.  The upper level ridge will produce easterly winds that will blow toward the top of the Tropical Low’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  The Tropical Low is likely to intensify during the next 24 hours.

The Tropical Low will move around the western side of a high pressure system over Australia.  The high pressure system will steer the Tropical Low toward the south-southwest during the next 24 hours.  The Tropical Low will move more toward the south later this week.  On its anticipated track, the Tropical Low will move toward the coast of Western Australia.

The Tropical Low is likely to intensify to a tropical cyclone before it reaches the coast of Western Australia.  It will bring strong winds and locally heavy rain to parts of Western Australia later this week.

A Watch is in effect for the portion of the coast from Cape Leveque to Port Hedland.  The Watch includes Broome, Wallal Downs, and De Grey.

A Flood Watch is in effect for the De Grey River and parts of the Sandy Desert catchments.

Elsewhere over the South Indian Ocean, Tropical Cyclone Vince moved farther away from Rodrigues and Tropical Cyclone Taliah moved farther away from the Cocos Islands.

At 4:00 p.m. EST on Monday the center of Tropical Cyclone Vince was located at latitude 25.4°S and longitude 68.6°E which put the center about 515 miles (835 km) southeast of Port Mathurin, Rodrigues.  Vince was moving toward the south at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 960 mb.

At 4:00 p.m. EST on Monday the center of Tropical Cyclone Taliah was located at latitude 14.2°S and longitude 92.2°E which put the center about 330 miles (530 km) west-southwest of the Cocos Islands.  Taliah was moving toward the west at 10 m.p.h. (16 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 992 mb.

Tropical Cyclone Ilsa Strengthens to Equivalent of Cat. 4 Hurricane

Tropical Cyclone Ilsa strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Ilsa was located at latitude 18.1°S and longitude 119.2°E which put it about 175 miles (285 km) northwest of Wallal Downs, Australia. Ilsa was moving toward the south-southwest at 7 m.p.h. (11 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 942 mb.

A Tropical Cyclone Warning was in effect for the coast of Western Australia from south of Broome to Whim Creek. The Warning included Port Hedland. The Tropical Cyclone Warning extended inland to include De Grey, Marble Bar, Nullagine, Telfer and Parnngurr.

Tropical Cyclone Ilsa strengthened to the equivalent of a Category 4 hurricane on Wednesday night. A small circular eye was present at the center of Ilsa’s circulation. The eye was surrounded by a ring of strong 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 Ilsa. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone. The removal of large quantities of mass was causing the surface pressure to continue to decrease.

A weather station at Rowley Shoals measured a sustained wind speed of 95 m.p.h. (83 kt or 154 km/h). The weather station measured a wind gust of 132 m.p.h. (115 kt or 213 km/h). It also measured a sea level pressure of 942.3 mb.

Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Tropical Cyclone Ilsa. Winds to tropical storm force extended out 120 miles (195 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Ilsa was 25.1. The Hurricane Size Index (HSI) was 13.4 and the Hurricane Wind Intensity Size Index (HWISI) was 38.5. Tropical Cyclone Ilsa was similar in size and intensity to Hurricane Harvey hit Texas in 2017.

Tropical Cyclone Ilsa will move through an environment favorable for intensification during the next 12 hours. Ilsa will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the axis of an upper level ridge that extends from northern Australia to 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 Ilsa could continue to intensify during the next 12 hours.

Tropical Cyclone Ilsa will move around the western end of a high pressure system over western Australia. The high pressure system will steer Ilsa toward the southeast during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Ilsa is likely to make landfall on the coast of Western Australia between Pardoo Roadhouse and Wallal Downs in 12 hours. Ilsa will be the equivalent of a major hurricane when it makes landfall.

Tropical Cyclone Ilsa will bring very strong winds and locally heavy rain to Western Australia between Pardoo Roadhouse and Wallal Downs. The strong winds will be capable of causing regional severe damage. Ilsa could also produce strong winds in De Grey and Telfer when it moves inland. Heavy rain could cause flash floods in some locations. Flood Watches are in effect for the West Kimberley, De Grey River, Sandy Desert, Western Desert, Warburton and Salt Lake Districts. Tropical Cyclone Ilsa could also cause a storm surge of up to 10 to 15 feet (3 to 4.5 meters) along the portion of the coast near where the center makes landfall.

Tropical Cyclone Ilsa Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Ilsa strengthened to the equivalent of a major hurricane over the South Indian Ocean northwest of Australia on Wednesday morning. At 11:00 a.m. EDT on Wednesday the center of Tropical Cyclone Ilsa was located at latitude 16.8°S and longitude 119.4°E which put it about 200 miles (325 km) west-northwest of Broome, Australia. Ilsa was moving toward the south-southwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h). The minimum surface pressure was 956 mb.

A Tropical Cyclone Warning was in effect for the portion of the coast of Western Australia from Bidyadanga to Port Hedland. Tropical Cyclone Watches were in effect for the portions of the coast from Broome to Bidyadanga and from Port Hedland to Whim Creek.

Tropical Cyclone Ilsa strengthened to the equivalent of a major hurricane on Wednesday morning. A small circular eye was present at the center of Ilsa’s circulation. The eye was surrounded by a ring of strong 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 Ilsa. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone. The removal of large quantities of mass was causing the surface pressure to continue to decrease.

The size of the circulation around Tropical Cyclone Ilsa increased, when Ilsa strengthened. Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Ilsa’s circulation. Winds to tropical storm force extended out 115 miles (185 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Ilsa was 20.6. The Hurricane Size Index (HSI) was 11.5 and the Hurricane Wind Intensity Size Index (HWISI) was 32.1. Tropical Cyclone Ilsa was similar in size and intensity to Hurricane Sally when Sally hit South Alabama in 2020.

Tropical Cyclone Ilsa will move through an environment very favorable for intensification during the next 24 hours. Ilsa will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the axis of an upper level ridge that extends from northern Australia to 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 Ilsa will continue to intensify during the next 24 hours. Ilsa could intensify rapidly at times.

Tropical Cyclone Ilsa will move around the western end of a high pressure system over western Australia. The high pressure system will steer Ilsa toward the south during the next 24 hours. Tropical Cyclone Ilsa will move toward the southeast when it reaches the western end of the high pressure system on Thursday morning. On its anticipated track, Ilsa is likely to make landfall on the coast of Western Australia between Broome and Port Hedland in 30 hours. The center of Tropical Cyclone Ilsa could make landfall near Wallal Downs. Ilsa is likely to be the equivalent of a major hurricane when it makes landfall.

Tropical Cyclone Ilsa will bring very strong winds and locally heavy rain to Western Australia near Wallal Downs. The strong winds will be capable of causing severe damage. Heavy rain could cause flash floods in some locations. Flood Watches are in effect for the West Kimberley, De Grey River, Sandy Desert, Western Desert, Warburton and Salt Lake Districts. Tropical Cyclone Ilsa could also cause a storm surge of up to 10 to 15 feet (3 to 4.5 meters) along the portion of the coast near where the center makes landfall.

Tropical Cyclone Ilsa Rapidly Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Ilsa rapidly intensified to the equivalent of a hurricane/typhoon on Tuesday. At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Ilsa was located at latitude 15.9°S and longitude 120.3°E which put it about 190 miles (305 km) northwest of Broome, Australia. Ilsa was moving toward the southwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (150 km/h). The minimum surface pressure was 975 mb.

A Tropical Cyclone Watch was in effect for the portion of the coast of Western Australia from Beagle Bay to Whim Creek. The Tropical Cyclone Watch included Broome and Port Hedland.

Tropical Cyclone Ilsa intensified rapidly over the South Indian Ocean northwest of Australia on Tuesday. The inner end of a rainband wrapped around the center of Ilsa’s circulation. Other bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated strong upper level divergence that pumped a large quantity of mass away from the tropical cyclone. The removal of a large quantity of mass caused the surface pressure to decrease rapidly, which contributed to the rapid increase in wind speed.

The circulation around Tropical Cyclone Ilsa was small. Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Ilsa’s circulation. Winds to tropical storm force extended out 75 miles (120 km) from the center of circulation.

Tropical Cyclone Ilsa will move through an environment very favorable for intensification during the next 24 hours. Ilsa will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the axis of an upper level ridge that extends from northern Australia to 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 Ilsa is likely to continue to intensify rapidly during the next 24 hours. Ilsa could intensify to the equivalent of a major hurricane within 24 hours.

Tropical Cyclone Ilsa will move around the northwestern part of a high pressure system over western Australia. The high pressure system will steer Ilsa toward the southwest during the next 18 hours. Tropical Cyclone Ilsa will move toward the south when it reaches the western end of the ridge on Wednesday. On its anticipated track, Ilsa is likely to make landfall on the coast of Western Australia between Broome and Port Hedland in 48 hours. The center of Tropical Cyclone Ilsa could make landfall near Wallal Downs. Ilsa is likely to be the equivalent of a major hurricane when it makes landfall.