Tag Archives: HWISI

Typhoon Mawar Rapidly Intensifies to Equivalent of Major Hurricane

Typhoon Mawar rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean south-southeast of Guam on Monday. At 5:00 p.m. EDT on Monday the center of Typhoon Mawar was located at latitude 10.8°N and longitude 146.7°E which put it about 255 miles (410 km) south-southeast of Guam. Mawar was moving toward the north-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 947 mb.

Typhoon Warnings were in effect for Guam and Rota. Tropical Storm Warnings were in effect for Tinian and Saipan. Typhoon Watches were also in effect for Tinian and Saipan.

Typhoon Mawar rapidly intensified to the equivalent of a major hurricane on Monday. A small circular eye was present at the center of Mawar’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Mawar. Storms near the core of Mawar’s circulation generated strong upper level divergence that pumped mass away from the tropical storm in all directions. The removal of mass continue to cause the surface pressure to decrease quickly.

The circulation around Typhoon Mawar was small. Winds to typhoon force extended out 25 miles (40 km) from the center of Mawar’s circulation. Winds to tropical storm force extended out 100 miles (160 km) from the center of Typhoon Mawar. The Hurricane Intensity Index (HII) for Typhoon Mawar was 23.6. The Hurricane Size Index (HSI) was 9.8 and the Hurricane Wind Intensity Size Index (HWISI) was 33.4. Mawar was similar in size and intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.

Typhoon Mawar will move through an environment favorable for intensification during the next 24 hours. Mawar will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Typhoon Mawar is likely to intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. If concentric eyewalls form, then an eyewall replacement cycle could cause Typhoon Mawar to weaken temporarily.

Typhoon Mawar will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Mawar toward the north-northwest during the next 24 hours. On its anticipated track, Typhoon Mawar will approach Guam in than 24 hours. Mawar is likely to be the equivalent of a major hurricane when it reaches the Marianas. Typhoon Mawar will bring strong winds and locally heavy rain to Guam, Rota, Tinian and Saipan. Mawar will be capable of causing regional severe damage when it reaches Guam. Typhoon Mawar will start to move south of a subtropical high pressure system when it approaches the Marianas. The subtropical high will steer Mawar more toward the west-northwest later this week.

Typhoon Mawar Prompts Warning for Guam

Typhoon Mawar prompted the issuance of a Typhoon Warning for Guam on Monday. At 11:00 a.m. EDT on Monday the center of Typhoon Mawar was located at latitude 10.3°N and longitude 146.8°E which put it about 290 miles (465 km) south-southeast of Guam. Mawar was moving toward the north-northwest at 6 m.p.h. (10 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 964 mb.

Typhoon Warning were in effect for Guam and Rota. Tropical Storm Warnings were in effect for Tinian and Saipan. Typhoon Watches were also in effect for Tinian and Saipan.

Typhoon Mawar continued to intensify on Monday morning. A small circular eye formed at the center of Mawar’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Mawar. Storms near the core of Mawar’s circulation generated strong upper level divergence that pumped mass away from the tropical storm in all directions. The removal of mass was causing the surface pressure to decrease.

The circulation around Typhoon Mawar was small. Winds to typhoon force extended out 40 miles (65 km) from the center of Mawar’s circulation. Winds to tropical storm force extended out 120 miles (190 km) from the center of Typhoon Mawar. The Hurricane Intensity Index (HII) for Typhoon Mawar was 17.8. The Hurricane Size Index (HSI) was 9.2 and the Hurricane Wind Intensity Size Index (HWISI) was 27.0. Mawar was similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.

Typhoon Mawar will move through an environment favorable for intensification during the next 36 hours. Mawar will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of the axis of an upper level ridge over the Equatorial Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Typhoon Mawar will intensify during the next 36 hours. Mawar could intensify more rapidly at times. Typhoon Mawar is likely to strengthen to the equivalent of a major hurricane within 36 hours.

Typhoon Mawar will move around the western end of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Mawar toward the north-northwest during the next 36 hours. On its anticipated track, Typhoon Mawar will approach Guam in 36 hours. Mawar could be the equivalent of a major hurricane when it reaches the Marianas. Typhoon Mawar will bring strong winds and locally heavy rain to Guam, Rota, Tinian and Saipan. Mawar will move south of a subtropical high pressure system when it approaches the Marianas. The subtropical high will steer Mawar more toward the west-northwest later this week.

Tropical Cyclone Fabien Moves Southeast of Diego Garcia

Tropical Cyclone Fabien moved southeast of Diego Garcia on Wednesday morning. At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Fabien was located at latitude 9.0°S and longitude 73.6°E which put it about 145 miles (235 km) southeast of Diego Garcia. Fabien was moving toward the southwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h). The minimum surface pressure was 959 mb.

Tropical Cyclone Fabien began to show signs of weakening on Wednesday morning. The clockwise circulation around Fabien was pulling drier air into the western side of the tropical cyclone. Thunderstorms in bands in the western half of Tropical Cyclone Fabien were weakening. Some bands consisted primarily of showers and lower clouds. The former circular eye was no longer visible on satellite images. There were still bands of showers and thunderstorms in the eastern half of Fabien’s circulation. Thunderstorms on the eastern side of Fabien still were generating upper level divergence that pumped mass away to the southeast of the tropical cyclone.

The circulation around Tropical Cyclone Fabien was small. Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Fabien’s circulation. Winds to tropical storm force extended out 90 miles (145 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Fabien was 19.2. The Hurricane Size Index (HSI) was 10.3 and the Hurricane Wind Intensity Size Index (HWISI) was 29.5. Tropical Cyclone Fabien was similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020

Tropical Cyclone Fabien will move through an environment unfavorable for intensification during the next 24 hours. Fabien will move over water where the Sea Surface Temperatures are near 28˚C. However, southerly winds in the western side of Fabien’s circulation will continue to pull drier air into the tropical cyclone. In addition, Tropical Cyclone Fabien will move under the southwestern part of an upper level ridge over the South Indian Ocean. The upper level ridge will produce northwesterly winds that will blow toward the top of Fabien’s circulation. Those winds will cause vertical wind shear. The drier air and vertical wind shear will cause Tropical Cyclone Fabien to weaken during the next 24 hours.

Tropical Cyclone Fabien will move around the northern side of a high pressure system over the South Indian Ocean. The high pressure system will steer Fabien toward the west-southwest during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Fabien will pass south of Diego Garcia during the next 24 hours. The high pressure system will steer Fabien more toward the west later this week. Tropical Cyclone Fabien will move southwest of Diego Garcia on Thursday.

Tropical Cyclone Fabien Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Fabien strengthened to the equivalent of a major hurricane over the South Indian Ocean east of Diego Garcia on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Fabien was located at latitude 7.6°S and longitude 74.8°E which put it about 180 miles (290 km) east of Diego Garcia. Fabien was moving toward the southwest at 8 m.p.h. (13 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.

Tropical Cyclone Fabien intensified to the equivalent of a major hurricane east of Diego Garcia on Tuesday morning. A small circular eye with a diameter of 15 miles (24 km) was present at the center of Fabien’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Fabien. Storms near the core generated upper level divergence that pumped mass away from the tropical cyclone.

The circulation around Tropical Cyclone Fabien was small. Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Fabien’s circulation. Winds to tropical storm force extended out 100 miles (160 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Fabien was 20.6. The Hurricane Size Index (HSI) was 8.6 and the Hurricane Wind Intensity Size Index (HWISI) was 29.0. Tropical Cyclone Fabien was similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.

Tropical Cyclone Fabien will move through an environment favorable for intensification during the next 24 hours. Fabien will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western side of the axis of an upper level ridge over 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 Fabien could continue to intensity during the next 24 hours.

Tropical Cyclone Fabien will move around the northern side of a high pressure system over the South Indian Ocean. The high pressure system will steer Fabien toward the southwest during the next 24 hours. On its anticipated track, Tropical Cyclone Fabien will move southeast of Diego Garcia during the next 24 hours. The high pressure system will steer Fabien more toward the west later this week. The center of Tropical Cyclone Fabien could be south of Diego Garcia in 36 hours.

Tropical Cyclone Mocha Hits Myanmar

Tropical Cyclone Mocha hits Myanmar on Sunday morning. At 5:00 a.m. EDT on Sunday the center of Tropical Cyclone Mocha was located at latitude 20.5°N and longitude 93.0°E which put it about 20 miles (30 km) north-northeast of Sittwe, Myanmar. Mocha was moving toward the northeast at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 195 m.p.h. (315 km/h). The minimum surface pressure was 919 mb.

The center of powerful Tropical Cyclone Mocha made landfall on the coast of Myanmar near Sittwe on Sunday morning. Mocha was near its peak intensity at the time of landfall. A circular eye with a diameter of 20 miles (32 km) was present at the center of Mocha’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Mocha.

Tropical Cyclone Mocha intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale at the time of landfall. Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Mocha’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Mocha was 33.2. The Hurricane Size Index (HSI) was 14.7 and the Hurricane Wind Intensity Size Index (HWISI) was 47.9. Tropical Cyclone Mocha was similar in size and intensity to Hurricane Michael when Michael hit Northwest Florida in 2018. Tropical Cyclone Mocha was capable of causing regional severe damage.

Tropical Cyclone Mocha will move around the western end of a high pressure system that extends from the Western North Pacific Ocean to Southeast Asia. The high pressure system will steer Mocha toward the northeast during the next 24 hours. Tropical Cyclone Mocha will bring very strong winds and locally heavy rain to Myanmar. The strong winds and heavy rain are likely to cause severe damage. Heavy rain is likely to cause flash floods in some locations. Mocha could also cause a storm surge of up to 13 feet (4 meters) along portions of the coast where the wind blows the water toward the shore. Tropical Cyclone Mocha will also bring gusty winds and heavy rain to eastern Bangladesh.

Powerful Tropical Cyclone Mocha Nears Myanmar and Bangladesh

Powerful Tropical Cyclone Mocha was nearing the coast of the Bay of Bengal near the border between Myanmar and Bangladesh on Saturday afternoon. At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Mocha was located at latitude 18.4°N and longitude 91.4°E which put it about 150 miles (240 km) south-southwest of Sittwe, Myanmar. Mocha was moving toward the north-northeast at 9 m.p.h. (15 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.

Tropical Cyclone Mocha continued to intensify on Saturday. A circular eye with a diameter of 20 miles (32 km) was present at the center of Mocha’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that band of storms. Storms near the center of circulation 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 allowed the surface pressure to decrease to 926 mb.

Tropical Cyclone Mocha intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Saturday. Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Mocha’s circulation. Winds to tropical storm force extended out 175 miles (280 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Mocha was 31.6. The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 43.6. Tropical Cyclone Mocha was similar in size and intensity to Hurricane Ida when Ida hit southeast Louisiana in 2021. Tropical Cyclone Mocha was capable of causing regional severe damage.

Tropical Cyclone Mocha will move through an environment favorable for a powerful tropical cyclone during the next few hours. Mocha will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the center of an upper level ridge over the Bay of Bengal. The upper level winds are weak near the center of the ridge and there will be little vertical wind shear. Tropical Cyclone Mocha is likely to maintain its intensity until it reaches land.

Tropical Cyclone Mocha will move around the western end of a high pressure system that extends from the Western North Pacific Ocean to Southeast Asia. The high pressure system will steer Mocha toward the north-northeast during the next 24 hours. Tropical Cyclone Mocha is likely to make landfall between Cox’s Bazar, Bangladesh and Sittwe, Myanmar in less than 12 hours. Mocha will be the equivalent of a major hurricane when it makes landfall. Tropical Cyclone Mocha will bring very strong winds and locally heavy rain to Myanmar and Bangladesh. The strong wind and rain is likely to cause severe damage. Heavy rain is likely to cause flash floods in some locations. Mocha could also cause a storm surge of up to 13 feet (4 meters) along portions of the coast where the wind blows the water toward the shore.

Tropical Cyclone Mocha Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Mocha strengthened to the equivalent of a major hurricane over the Bay of Bengal on Friday. At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Mocha was located at latitude 15.2°N and longitude 88.9°E which put it about 545 miles (880 km) south-southwest of Cox’s Bazar, Bangladesh. Mocha was moving toward the north-northeast at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 945 mb.

Tropical Cyclone Mocha rapidly intensified to the equivalent of a major hurricane over the Bay of Bengal on Friday. A circular eye was present at the center of Mocha’s circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that band of storms. Storms near the center of circulation generated strong upper level divergence that pumped a large quantity of mass away from the tropical cyclone. The removal of mass allowed the surface pressure to decrease rapidly.

The circulation around Tropical Cyclone Mocha was large. Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Mocha’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Mocha was 23.6. The Hurricane Size Index (HSI) was 12.6 and the Hurricane Wind Intensity Size Index (HWISI) was 36.2. Tropical Cyclone Mocha was capable of causing major damage.

Tropical Cyclone Mocha will move through an environment favorable for intensification during the next 24 hours. Mocha will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the center of an upper level ridge over the Bay of Bengal. The upper level winds are weak near the center of the ridge and there will be little vertical wind shear. Tropical Cyclone Mocha is likely to intensify during the next 24 hours.

Tropical Cyclone Mocha will move around the western end of a high pressure system that extends from the Western North Pacific Ocean to Southeast Asia. The high pressure system will steer Mocha toward the north-northeast during the next 48 hours. Tropical Cyclone Mocha is likely to make landfall near the border between Bangladesh and Myanmar during the weekend. Mocha is likely to be the equivalent of a major hurricane when it makes landfall. Tropical Cyclone Mocha will bring strong winds and locally heavy rain to Myanmar and Bangladesh. Heavy rain is likely to cause flash floods in some locations. Mocha could also cause a storm surge of up to 13 feet (4 meters) along portions of the coast where the wind blows the water toward the shore.

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.