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Tropical Cyclone Zelia Approaches Coast of Western Australia

Tropical Cyclone Zelia was approaching the coast of Western Australia near Port Hedland on Thursday night.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Zelia was located at latitude 19.8°S and longitude 118.7°E which put the center about 55 miles (90 km) north of Port Hedland, Australia.  Zelia was moving toward the south-southeast at 5 m.p.h. (8 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 938 mb.

Concentric eyewalls developed at the center of Tropical Cyclone Zelia on Thursday.  The inner end of a rainband wrapped around the original eye and eyewall.  The inner eyewall had a diameter of 15 miles (24 km). The outer eyewall had a diameter of 38 miles (61 km).  The development of concentric eyewalls halted the intensification of Tropical Cyclone Zelia.

Bands of showers and thunderstorms were revolving around the concentric eyewalls at 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 in the upper levels was nearly the same as the inflow of mass in the lower levels of the atmosphere.  So, the surface pressure remained fairly constant.

The circulation around Tropical Cyclone Zelia was symmetrical.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Zelia’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Tropical Cyclone Zelia.

The Hurricane Intensity Index (HII) for Tropical Cyclone Zelia was 25.1.  The Hurricane Size Index (HSI) was 13.9 and the Hurricane Wind Intensity Size Index (HWISI) was 39.0.  Tropical Cyclone Zelia was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Tropical Cyclone Zelia will move through an environment favorable for intensification during the next few 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.  Even though Tropical Cyclone Zelia will move through a favorable environment, the concentric eyewalls are likely to prevent any significant intensification.

Tropical Cyclone Zelia will move around the northwestern 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, the center of Tropical Cyclone Zelia will make landfall on the coast of Western Australia near Port Hedland in a few hours.

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

A Warning is in effect for the portion of the coast from Wallal Downs to Roebourne.   The Warning includes Port Hedland and De Grey.  The Warning extends inland to Marble Bar, Millstream, Nullagine, Tom Price, and Paraburdoo.

Heavy rain is likely to cause floods in some locations.

A Flood Warning is in effect for the De Grey River.  A Flood Warning is in effect for the Pilbara coastal Rivers.

Flood Watches are in effect for the Onslow coast, the Fortescue River, the Ashburton River, the Gascoyne River, and parts of the Sandy Desert.

Tropical Cyclone Zelia Rapidly Intensifies to Equivalent of Major Hurricane

Tropical Cyclone Zelia rapidly intensified to the equivalent of a major hurricane near the coast of Western Australia on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Zelia was located at latitude 19.1°S and longitude 118.1°E which put the center about 80 miles (130 km) north-northwest of Port Hedland, Australia.  Zelia was nearly stationary.  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 940 mb.

Tropical Cyclone Zelia rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Thursday.  A small circular eye with a diameter of 12 miles (19 km) formed at the center of Zelia’s circulation.  A ring of thunderstorms surrounded the center of Zelia and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Zelia.  Storms near the core 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 Zelia was symmetrical.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Zelia’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Cyclone Zelia.

The Hurricane Intensity Index (HII) for Tropical Cyclone Zelia was 28.3.  The Hurricane Size Index (HSI) was 14.1 and the Hurricane Wind Intensity Size Index (HWISI) was 42.4.

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 continue to intensify during the next 24 hours.  Zelia could intensify rapidly at times.  Tropical Cyclone Zelis could strengthen to the equivalent of Category 5 hurricane on the Saffir-Simpson Scale.

Tropical Cyclone Zelia will move around the northwestern side of a high pressure system over Australia.  The high pressure system will steer Zelia slowly toward the southwest 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 Port Hedland and Dampier in 36 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 Bidyadanga to Dampier.  The Warning includes Port Hedland, Karratha, De Grey, and Wallal Downs.  The Warning extends inland to Marble Bar.

A Watch is in effect for the portion of the coast from Dampier to Mardie.  The Watch extends inland to Nullagine and Tom Price.

Heavy rain is likely to cause floods in some locations.

A Flood Warning is in effect for the De Grey River.

Flood Watches are in effect for the Pilbara coastal Rivers, the Onslow coast, the Fortescue River, the Ashburton River, and parts of the Sandy Desert.

Tropical Cyclone Zelia Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Zelia intensified to the equivalent of a hurricane/typhoon near the coast of Western Australia early on Wednesday.  At 4:00 a.m. EST on Wednesday the center of Tropical Cyclone Zelia was located at latitude 19.1°S and longitude 118.6°E which put the center about 80 miles (130 km) north of Port Hedland, Australia.  Zelia was moving toward the south-southwest at 3 m.p.h. (5 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.

Tropical Cyclone Zelia exhibited signs of rapid intensification early on Wednesday.  The inner end of a rainband wrapped around the center of Zelia’s circulation.  A small eye appeared to be forming at the center of Tropical Cyclone Zelia.  A ring of thunderstorms surrounded the center of Zelia and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Zelia.  Storms near the core 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 was symmetrical.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Zelia’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Cyclone Zelia.

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 could intensify rapidly at times.  Tropical Cyclone Zelis could strengthen to the equivalent of a major hurricane.

Tropical Cyclone Zelia will move around the northwestern side of a high pressure system over Australia.  The high pressure system will steer Zelia slowly toward the west-southwest 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 De Grey and Dampier in 36 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 Bidyadanga to Dampier.  The Warning includes Port Hedland, Karratha, De Grey, and Wallal Downs.  The Warning extends inland to Marble Bar.

A Watch is in effect for the portion of the coast from Dampier to Mardie.  The Warning extends inland to Nullagine.

Heavy rain is likely to cause floods in some locations.

A Flood Warning is in effect for the De Grey River.

Flood Watches are in effect for the Pilbara coastal Rivers, the Onslow coast, the Fortescue River, the Ashburton River, and parts of the Sandy Desert.

Elsewhere over the South Indian Ocean, Tropical Cyclone Vince made a transition to an extratropical cyclone and Tropical Cyclone Taliah continued to move farther away from the Cocos Islands.

At 4:00 a.m. EST on Wednesday the center of Tropical Cyclone Taliah was located at latitude 18.2°S and longitude 90.3°E which put the center about 565 miles (915 km) south-southwest of the Cocos Islands.  Taliah was moving toward the southwest at 15 m.p.h. (24 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 984 mb.

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 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 Ilsa Hits Western Australia

The center of Tropical Cyclone Ilsa hit the coast of Western Australia just to the east of Pardoo Roadhouse on Thursday. At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Ilsa was located at latitude 19.9°S and longitude 119.7°E which put it about 10 miles (15 km) northeast of Pardoo Roadhouse, Australia. Ilsa was moving toward the southeast at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 926 mb.

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

Tropical Cyclone Ilsa was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale at the time of landfall. A very 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.

A weather station at Bedout Island measured a sustained wind speed of 135 m.p.h. (218 km/h) when the western side of the eyewall of Tropical Cyclone Ilsa passed over it. The weather station also measured a wind gust of 178 m.p.h. (288 km/h).

Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Tropical Cyclone Ilsa at the time of landfall. Winds to tropical storm force extended out 140 miles (225 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Ilsa was 31.6. The Hurricane Size Index (HSI) was 17.6 and the Hurricane Wind Intensity Size Index (HWISI) was 49.2. Tropical Cyclone Ilsa was similar in size and intensity to Hurricane Laura when Laura hit southwest Louisiana in 2020.

Tropical Cyclone Ilsa will move around the southern side of a high pressure system over northern Australia. The high pressure system will steer Ilsa toward the east-southeast during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Ilsa will pass near Telfer and Kiwirrkurra.

Although Tropical Cyclone Ilsa will weaken as it moves farther inland over Western Australia, it will take a while to spin down. Ilsa will bring strong winds and locally heavy rain to Western Australia. 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 Warnings are in effect for the De Grey River and the Sandy Desert. Flood Watches are in effect for the West Kimberley, Western Desert, Warburton and Salt Lake Districts. Tropical Cyclone Ilsa could bring gusty winds to Kiwirrkurra during Friday.

Powerful Tropical Cyclone Ilsa Nears Western Australia

Powerful Tropical Cyclone Ilsa neared the coast of Western Australia on Thursday morning. At 5:00 a.m. EDT on Thursday the center of Tropical Cyclone Ilsa was located at latitude 19.1°S and longitude 119.1°E which put it about 75 miles (120 km) northwest of Pardoo Roadhouse, Australia. Ilsa was moving toward the south-southeast at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 926 mb.

A Tropical Cyclone Warning was in effect for the coast of Western Australia from Bidyadanga 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 continued to intensify during Wednesday night, as it moved closer to the coast of Western Australia. A very 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 Bedout Island measured a sustained wind speed of 120 m.p.h. (104 kt or 193 km/h) as the core of Tropical Cyclone Ilsa was approaching it. The weather station also measured a wind gust of 144 m.p.h. (125 kt or 232 km/h).

The size of the circulation around Tropical Cyclone Ilsa increased as it intensified. Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of Tropical Cyclone Ilsa. Winds to tropical storm force extended out 140 miles (225 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Ilsa was 31.6. The Hurricane Size Index (HSI) was 18.4 and the Hurricane Wind Intensity Size Index (HWISI) was 50.0. Tropical Cyclone Ilsa was similar in size and intensity to Hurricane Laura when Laura hit southwest Louisiana in 2020.

Tropical Cyclone Ilsa will move through an environment favorable for a powerful tropical cyclone during the next few 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 maintain its intensity until it reaches the coast of Western Australia.

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 near Pardoo Roadhouse in 6 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 De Grey 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 Warnings are in effect for the De Grey River and the Sandy Sesert. Flood Watches are in effect for the West Kimberley, 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 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 Anika Moves Back over Water

The center of Tropical Cyclone Anika moved back over water on Monday night. At 10:00 p.m. EST on Monday the center of Tropical Cyclone Anika was located at latitude 16.7°S and longitude 122.5°E which put it about 85 miles (140 km) north of Broome, Australia. Anika was moving toward the west-southwest at 8 m.p.h (13 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 center of Tropical Cyclone Anika moved back over water near Beagle Bay on Monday night. New thunderstorms began to develop near the center of Anika after the center moved back over water. The strongest thunderstorms were occurring in bands southwest of the center of circulation and northeast of the center. Bands in other parts of Tropical Cyclone Anika consisted primarily of showers and lower clouds. Storms near the center of Anika began to generated more upper level divergence.

Tropical Cyclone Anika will move around the northwestern part of a high pressure system over Australia during the next 24 hours. The high pressure system will steer Anika toward the southwest during that time period. Anika will move toward the south after it reaches the western end of the high pressure system in 24 hours. On its anticipated track Tropical Cyclone Anika could make landfall on the coast of Western Australia between Bidyadanga and De Grey in 42 hours.

Tropical Cyclone Anika will move through an environment favorable for intensification during the next 24 hours. Anika will move over water where the Sea Surface Temperatures are near 30˚C. It will move through are region where the upper level winds are weak and there will be little vertical wind shear. Tropical Cyclone Anika will strengthen during the next 24 hours. However a portion of Anika’s circulation will still be over land, which will inhibit intensification.

Tropical Cyclone Anika will continue to bring gusty winds and locally heavy rain to parts of the coast of Western Australia. A Warning is in effect for the portion of the coast from Beagle Bay to Bidyadanga. The Warning includes Broome. A Watch is in effect for the portion of the coast from Bidyadanga to De Grey. Locally heavy rain could cause flash floods in some locations. Flood Watches are in effect for the Fitzroy River, the De Grey River and the Sandy Desert.

Elsewhere over the South Indian Ocean, Tropical Cyclone Vernon continued to spin east-southeast of Diego Garcia. At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Vernon was located at latitude 14.6°S and longitude 87.0°E which put it about 1115 miles (1785 km) east-southeast of Diego Garcia. Vernon was moving toward the south-southwest at 4 m.p.h (6 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 994 mb.