Tag Archives: HWISI

Tropical Cyclone Garance Intensifies to Equivalent of Major Hurricane

Tropical Cyclone Garance intensified to the equivalent of a major hurricane north of La Reunion on Thursday.  At 4:00 a.m. EST on Thursday the center of Tropical Cyclone Garance was located at latitude 18.5°S and longitude 55.4°E which put the center about 155 miles (205 km) north of St. Denis, La, Reunion.  Garance was moving toward the southeast at 5 m.p.h. (8 km/h). 0 The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 955 mb.

Tropical Cyclone Garance intensified to the equivalent of a major hurricane north of La Reunion on Thursday.  A circular eye with a diameter of 17 miles (28 km) was at the center of Garance’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 center of Garance’s circulation.  Storms near the center 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 Garance was small.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Garance’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Tropical Cyclone Garance.

The Hurricane Intensity Index (HII) for Tropical Cyclone Garance was 22.1.  The Hurricane Size Index (HSI) was 12.3 and the Hurricane Wind Intensity Size Index (HWISI) was 34.4. Tropical Cyclone Garance was similar in size and intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.

Tropical Cyclone Garance will move through an environment favorable for intensification during the next 12 hours.  Garance will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under an upper level ridge that is east of Madagascar.  The upper level winds are weak in the ridge and there will be little vertical wind shear.  Tropical Cyclone Garance could continue to intensify during the next 12 hours unless an eyewall replacement cycle occurs.

Tropical Cyclone Garance is likely to get pulled into the eastern side of the larger circulation around Tropical Cyclone Honde, which is over the southern Mozambique Channel.  The larger circulation around Honde will steer Garance toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone Garance will reach La Reunion within the next 18 hours.

Tropical Cyclone Garance is likely to be the equivalent of a major hurricane when it reaches La Reunion.  Garance will be capable of causing major damage on La Reunion.  Tropical Cyclone Garance will also drop heavy rain on La Reunion.  Heavy rain is likely to cause widespread flash flooding.  Garance could cause a storm surge of up to 10 feet (3 meters) along the coast of La Reunion.

Bands in the eastern side of Tropical Cyclone Garance could also bring strong winds and heavy rain to Mauritius.  There were reports that the airport on Mauritius was closed as a precaution.

Elsewhere, Tropical Cyclone Honde intensified to the equivalent of a hurricane/typhoon over the southern Mozambique Channel near Madagascar.  At 4:00 a.m. EST on Thursday the center of Tropical Cyclone Honde was located at latitude 25.0°S and longitude 41.8°E which put the center about 170 miles (280 km) southwest of Toliara, Madagascar.  Honde was moving toward the southeast at 13 m.p.h. (21 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 970 mb.

Tropical Cyclone Honde will bring strong winds and locally heavy rain to southern Madagascar.  Heavy rain is likely to cause flash floods in some locations.

Tropical Cyclone Alfred Continues to Strengthen

Tropical Cyclone Alfred continued to strengthen over the Coral Sea on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Alfred was located at latitude 17.0°S and longitude 155.5°E which put the center about 660 miles (1050 km) north-northeast of Brisbane, Australia.  Alfred was moving toward the south at 7 m.p.h. (11 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 962 mb.

Tropical Cyclone Alfred continued to strengthen over the Coral Sea on Wednesday.  A very small circular eye was visible at the center of Alfred’s circulation on satellite images.  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 Alfred.  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 size of the circulation around Tropical Cyclone Alfred increased when Alfred strengthened on Wednesday.  Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of Alfred’s circulation.  Winds to tropical storm force extended out 200 miles (325 km) from the center of Tropical Cyclone Alfred.

The Hurricane Intensity Index (HII) for Tropical Cyclone Alfred is 19.2.  The Hurricane Size Index (HSI) is 22.7 and the Hurricane Wind Intensity Size Index (HWISI) is 41.9.  Tropical Cyclone Alfred is similar in size and intensity to Hurricane Gustav when Gustav hit Louisiana in 2008.

Tropical Cyclone Alfred will move through an environment favorable for intensification during the next 24 hours.  Alfred will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge over the Coral Sea.  The winds are weak near the middle of the upper level ridge and there will be little vertical wind shear.  Tropical Cyclone Alfred is likely 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 will form.  If concentric eyewalls form, then an eyewall replacement cycle will cause Alfred to weaken.

Tropical Cyclone Alfred will move around the western side of a high pressure system that is over Vanuatu.  The high pressure system will steer Alfred toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone Alfred will move parallel to the east coast of Australia.  Alfred could move closer to the coast of Queensland by the weekend.

Tropical Cyclone Garance Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Garance intensified to the equivalent of a hurricane/typhoon north-northwest of La Reunion on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Garance was located at latitude 17.8°S and longitude 54.7°E which put the center about 200 miles (325 km) north-northwest of St. Denis, La, Reunion.  Garance was moving toward the east-southeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 974 mb.

Tropical Cyclone Garance rapidly intensified to the equivalent of a hurricane/typhoon over the Southwest Indian Ocean north-northwest of La Reunion on Wednesday.  The inner end of a rainband wrapped around the center of Garance’s circulation.  A small circular eye appeared to be forming at the center of Tropical Cyclone Garance.  The developing 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 center of Garance’s circulation.  Storms near the center 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 Garance was small.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Garance’s circulation.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Garance.

The Hurricane Intensity Index (HII) for Tropical Cyclone Garance was 16.5  The Hurricane Size Index (HSI) was 11.2 and the Hurricane Wind Intensity Size Index (HWISI) was 27.7.  Tropical Cyclone Garance was similar in size and intensity to Hurricane Idalia when Idalia hit Florida in 2023.

Tropical Cyclone Garance will move through an environment favorable for intensification during the next 24 hours.  Garance will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the northern side of an upper level low that is southeast of La Reunion.  The upper level low will produce westerly winds that will blow toward the top of Garance’s circulation.  Those winds will some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification. Tropical Cyclone Garance will intensify during the next 24 hours.  Garance is likely to strengthen to the equivalent of a major hurricane.

Tropical Cyclone Garance could get pulled into the eastern side of the larger circulation around Tropical Cyclone Honde, which is over the Mozambique Channel.  The larger circulation around Honde will steer Garance toward the south during the next 24 hours.  On its anticipated track, Garance will approach La Reunion in 24 hours.

Tropical Cyclone Garance is likely to be the equivalent of a major hurricane when it reaches La Reunion.  Garance will be capable of causing major damage on La Reunion.  Tropical Cyclone Garance will also drop heavy rain on La Reunion.  Heavy rain is likely to cause widespread flash flooding.  Garance could cause a storm surge of up to 10 feet (3 meters) along the coast of La Reunion.

Elsewhere, Tropical Cyclone Honde was intensifying over the Mozambique Channel.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Honde was located at latitude 24.1°S and longitude 40.2°E which put the center about 255 miles (410 km) west of Toliara, Madagascar. Honde was moving toward the east-southeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 981 mb.

Tropical Cyclone Bianca Strengthens to Equivalent of Major Hurricane

Tropical Cyclone Bianca strengthened to the equivalent of a major hurricane on Monday night.  At 4:00 a.m. EST on Tuesday the center of Tropical Cyclone Bianca was located at latitude 22.3°S and longitude 102.0°E which put the center about 765 miles (1235 km) west of the Exmouth, Australia.  Bianca was moving toward the south-southwest at 11 m.p.h. (17 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. (235 km/h).  The minimum surface pressure was 962 mb.

Tropical Cyclone Bianca strengthened to the equivalent of a major hurricane over the South Indian Ocean west of Australia on Monday night.  A circular eye with a diameter of 20 miles (32 km) was at the center of Bianca’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 revolved around the center of Bianca’s circulation.  Storms near the center of Bianca generated upper level divergence that pumped mass away from the tropical cyclone.

The circulation around Tropical Cyclone Bianca was small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Bianca’s circulation.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Bianca.

The Hurricane Intensity Index (HII) for Tropical Cyclone Bianca was 20.6.  The Hurricane Size Index (HSI) was 9.3 and the Hurricane Wind Intensity Size Index (HWISI) was 29.9.

Tropical Cyclone Bianca will move into an environment that will become unfavorable for intensification during the next 24 hours.  Bianca will move over water where where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level trough over the South Indian Ocean.  The upper level trough will produce northwesterly winds that will blow toward the top of Bianca’s circulation.  Those winds will cause the vertical wind shear to increase.  Tropical Cyclone Bianca will weaken when the vertical wind shear increases.

Tropical Cyclone Bianca will move around the western part of a high pressure system over the South Indian Ocean.  The high pressure system will steer Bianca toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone Bianca will move parallel to the coast of Western Australia.

Tropical Cyclone Zelia Brings Wind and Rain to Western Australia

Tropical Cyclone Zelia brought wind and rain to Western Australia on Friday.  At 7:00 a.m. EST on Friday the center of Tropical Cyclone Zelia was located at latitude 21.1°S and longitude 119.6°E which put the center about 10 miles (20 km) west-northwest of Marble Bar, Australia.  Zelia was moving toward the south-southeast at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 965 mb.

The center of Tropical Cyclone Zelia made landfall on the coast of Western Australia about 45 miles (75 km) northeast of Port Hedland on Thursday night.  Zelia was the equivalent of a major hurricane at the time of landfall.  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).

At the time of landfall 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 brought strong winds and heavy rain to parts of Western Australia east of Port Hedland.  A weather station in Port Hedland reported a sustained wind speed of 50 m.p.h. (80 km/h).  The weather station reported a wind gust of 75 m.p.h. (120 km/h).  The weather station also reported 6.14 inches (156 mm) of rain.

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 will move around the northwestern side of a high pressure system over Australia.  The high pressure system will steer Zelia toward the south during the next 24 hours.  On its anticipated track, the center of Tropical Cyclone Zelia will pass between Nullagine and Munjina.

Tropical Cyclone Zelia will weaken steadily as it moves inland over Western Australia.  Zelia will continue to bring strong winds and heavy rain to parts of Western Australia as it weakens.  Heavy rain could cause additional flooding in some locations.

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 Vince Moves Away From Rodrigues

Tropical Cyclone Vince moved farther away from Rodrigues on Sunday.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Vince was located at latitude 21.9°S and longitude 69.1°E which put the center about 410 miles (660 km) east-southeast of Port Mathurin, Rodrigues.  Vince was moving toward the south-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 952 mb.

Tropical Cyclone Vince continued to gradually weaken as it moved away from Rodrigues on Sunday.  Even though Vince was weakening, the circulation around the tropical cyclone remained well organized.  A circular eye with a diameter of 45 miles (73 km) was at the center of Vince’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 revolved around the core of Tropical Cyclone Vince.  Storms near the core of Vince generated upper level divergence that pumped mass away from the tropical cyclone.  The divergence of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased gradually.

The circulation around Tropical Cyclone Vince was still very well organized.  Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of Vince’s circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center of Tropical Cyclone Vince.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince is 22.1.  The Hurricane Size Index (HSI) is 19.2 and the Hurricane Wind Intensity Size Index (HWISI) is 41.3.  Tropical Cyclone Vince is similar in intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.  Vince is much larger than Dennis was.

.Tropical Cyclone Vince will move through an environment that will become even less favorable for an intense tropical cyclone during the next 24 hours.  Vince will move over water where where the Sea Surface Temperatures are near 27°C.  It will move under the eastern side of an upper level trough southeast of Madagascar.  The upper level tough will produce northwesterly winds that will blow toward the top of Vince’s circulation.  Those winds will cause the vertical wind shear to increase.  More vertical wind shear will cause Tropical Cyclone Vince to continue to weaken during the next 24 hours.

Tropical Cyclone Vince will move around the western part of a high pressure system over the South Indian Ocean.  The high pressure system will steer Vince toward the south during the next 24 hours.  On its anticipated track Tropical Cyclone Vince will continue to move farther away from Rodrigues.

Elsewhere over the South Indian Ocean, Tropical Cyclone Taliah continued to weaken southwest of the Cocos Islands.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Taliah was located at latitude 14.8°S and longitude 93.2°E which put the center about 410 miles (660 km) southwest of the Cocos Islands.  Taliah was moving toward the west at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 999 mb.

Tropical Cyclone Vince Spins East of Rodrigues

Tropical Cyclone Vince continued to spin over the South Indian Ocean east of Rodrigues on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Vince was located at latitude 20.6°S and longitude 71.2°E which put the center about 525 miles (850 km) east of Port Mathurin, Rodrigues.  Vince was moving toward the west at 10 m.p.h. (16 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 946 mb.

Tropical Cyclone Vince weakened gradually as it continued to spin over the South Indian Ocean east of Rodrigues.  A circular eye with a diameter of 40 miles (65 km) was at the center of Vince’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 revolved around the core of Tropical Cyclone Vince.  Storms near the core of Vince generated upper level divergence that pumped mass away from the tropical cyclone.  The divergence of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased gradually.

The circulation around Tropical Cyclone Vince was still very well organized.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Vince’s circulation.  Winds to tropical storm force extended out 160 miles (260 km) in the southern half of Tropical Cyclone Vince.  Winds to tropical storm force extended out 75 miles in the northern side of Vince’s circulation.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince is 25.1.  The Hurricane Size Index (HSI) is 12.6 and the Hurricane Wind Intensity Size Index (HWISI) is 37.7.  Tropical Cyclone Vince is similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017

.Tropical Cyclone Vince will move through an environment that will become less favorable for an intense tropical cyclone during the next 24 hours.  Vince will move over water where where the Sea Surface Temperatures are near 27°C.  It will move under the southern part of an upper level ridge over the South Indian Ocean.  The upper level ridge will produce westerly winds that will blow toward the top of Vince’s circulation.  Those winds will cause the vertical wind shear to increase. More vertical wind shear will cause Tropical Cyclone Vince to continue to weaken gradually during the next 24 hours.

Tropical Cyclone Vince will move around the northwestern part of a high pressure system over the South Indian Ocean.  The high pressure system will steer Vince toward the southwest during the next 24 hours.  On its anticipated track Tropical Cyclone Vince will move closer to Rodrigues.  Vince is likely to start to move toward the south when it reaches the western end of the high pressure system on Monday.

Elsewhere over the South Indian Ocean, Tropical Cyclone Taliah was moving farther away from the Cocos Islands.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Taliah was located at latitude 15.6°S and longitude 94.4°E which put the center about 285 miles (455 km) south of the Cocos Islands.  Taliah was moving toward the west at 6 m.p.h. (10 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.

Powerful Tropical Cyclone Vince Passes South of Diego Garcia

Powerful Tropical Cyclone Vince was passing far to the south of Diego Garcia on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Vince was located at latitude 20.1°S and longitude 75.3°E which put the center about 925 miles (1495 km) south-southeast of Diego Garcia.  Vince was moving toward the west at 13 m.p.h. (21 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 932 mb.

Powerful Tropical Cyclone Vince maintained its intensity as it passed far to the south of Diego Garcia on Friday.  A circular eye with a diameters of 23 miles (37 km) was at the center of Vince’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the center of Vince generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone.  The divergence of mass in the upper levels of the atmosphere was almost balanced by the inflow of mass in the lower levels.  The effect of the near balance of divergence and inflow was to keep the surface pressure nearly steady.

The circulation around Tropical Cyclone Vince was very symmetrical.  Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Vince’s circulation.  Winds to tropical storm force extended out 140 miles (220 km) from the center of Tropical Cyclone Vince.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince is 31.6.  The Hurricane Size Index (HSI) is 15.6 and the Hurricane Wind Intensity Size Index (HWISI) is 47.2.  Tropical Cyclone Vince is similar in size and intensity to Hurricane Ida when Ida hit Louisiana in 2021

.Tropical Cyclone Vince will move through an environment favorable for an intense tropical cyclone during the next 24 hours.  Vince will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the northern part of an upper level ridge over the South Indian Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Vince’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Cyclone Vince is likely to maintain its intensity during the next 24 hours, unless an eyewall replacement cycle occurs.

Tropical Cyclone Vince will move around the northern side of a high pressure system over the South Indian Ocean.  The high pressure system will steer Vince toward the west-southwest during the next 24 hours.  On its anticipated track Tropical Cyclone Vince will move toward Rodrigues.

Elsewhere over the South Indian Ocean, Tropical Cyclone Taliah was passing south of the Cocos Islands.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Taliah was located at latitude 15.8°S and longitude 96.4°E which put the center about 250 miles (400 km) south of the Cocos Islands.  Taliah was moving toward the west at 15 m.p.h. (24 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 986 mb.