Tag Archives: HWISI

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.

Tropical Cyclone Vince Intensifies to Equivalent of Cat. 4 Hurricane

Tropical Cyclone Vince intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale over the South Indian Ocean far to the south-southeast of Diego Garcia on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Vince was located at latitude 19.8°S and longitude 80.2°E which put the center about 985 miles (1590 km) south-southeast of Diego Garcia.  Vince was moving toward the west-southwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 924 mb.

Tropical Cyclone Vince intensified to the equivalent of a Category 4 hurricane on Thursday.  A circular eye with a diameter of 17 miles (28 km) was at the center of Vince’s circulation.  The eye was surrounded by a ring of strong 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 in all directions.  The removal of large amounts of mass caused the surface pressure to decrease rapidly,

The size of the circulation around Tropical Cyclone Vince decreased when Vince intensified on Thursday.  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 110 miles (175 km) from the center of Tropical Cyclone Vince.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince is 33.3.  The Hurricane Size Index (HSI) is 16.0 and the Hurricane Wind Intensity Size Index (HWISI) is 49.3.  Tropical Cyclone Vince is similar in size and intensity to Hurricane Ian when Ian hit Southwest Florida in 2022.

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 could intensify 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 pass far to the south of Diego Garcia.

Elsewhere, Tropical Cyclone Taliah continued to spin east-southeast of the Cocos Islands.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Taliah was located at latitude 14.5°S and longitude 101.0°E which put the center about 345 miles (500 km) east-southeast of the Cocos Islands.  Taliah was moving toward the west at 12 m.p.h. (19 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 984 mb.

Tropical Cyclone Vince Churns Southeast of Diego Garcia

Tropical Cyclone Vince churned over the South Indian Ocean far to the southeast of Diego Garcia on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Vince was located at latitude 18.9°S and longitude 83.5°E which put the center about 945 miles (1525 km) southeast of Diego Garcia.  Vince was moving toward the west at 9 m.p.h. (15 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 951 mb.

Tropical Cyclone Vince completed an eyewall replacement cycle on Wednesday.  Vince began to intensify again after it completed the eyewall replacement cycle.  A new circular eye was present 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.  Even though Tropical Cyclone Vince was the equivalent of a major hurricane, the distribution of thunderstorms was asymmetrical.  Thunderstorms were occurring in bands in the northern and western parts of Vince’s circulation.  Bands in the eastern and southern parts of Tropical Cyclone Vince consisted primarily of showers and lower clouds.  Storms near the center of Vince 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 Vince increased as a result of the eyewall replacement cycle.  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 140 miles (225 km) from the center of Tropical Cyclone Vince.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince is 23.6.  The Hurricane Size Index (HSI) is 14.4 and the Hurricane Wind Intensity Size Index (HWISI) is 38.0.  Tropical Cyclone Vince is similar in intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.  Vince is larger than Dennis was.

Tropical Cyclone Vince will move through an environment favorable for intensification 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 intensify during the next 24 hours, unless another 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 pass far to the south of Diego Garcia later this week.

Elsewhere, Tropical Cyclone Taliah weakened gradually as it spun east-southeast of the Cocos Islands. At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Taliah was located at latitude 14.8°S and longitude 105.5°E which put the center about 635 miles (1025 km) east-southeast of the Cocos Islands.  Taliah was moving toward the west at 8 m.p.h. (13 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 984 mb.

Tropical Cyclone Vince Intensifies to Equivalent of a Major Hurricane

Tropical Cyclone Vince intensified to the equivalent of a major hurricane over the South Indian Ocean southwest of the Cocos Islands during Monday night.  At 4:00 a.m. EST on Tuesday the center of Tropical Cyclone Vince was located at latitude 18.6°S and longitude 89.6°E which put the center about 595 miles (960 km) southwest of the Cocos Islands.  Vince was moving toward the southwest at 12 m.p.h. (19 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 958 mb.

Tropical Cyclone Vince intensified to the equivalent of a major hurricane during Monday night.  Vince appeared to go through an eyewall replacement cycle after it intensified.  The inner end of a rainband wrapped around the original small eye at the center of Vince’s circulation.  The small eye dissipated and a larger outer eye formed.

The circulation around Tropical Cyclone Vince weakened after the eyewalll replacement cycle.  A ring of thunderstorms surrounded the new larger eye.  The strongest winds were occurring in that ring of storms.  The distribution of thunderstorms around Tropical Cyclone Vince was asymmetrical.  Most of the thunderstorms were occurring in bands in the western side of Vince’s circulation.  Bands in the eastern side of Tropical Cyclone Vince consisted primarily of showers and lower clouds.  Storms near the center of Vince generated upper level divergence that pumped mass away to the west of the tropical cyclone.

The eyewall replacement cycle caused the size of the circulation around Tropical Cyclone Vince to increase.  Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of Vince’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Tropical Cyclone Vince.

The Hurricane Intensity Index (HII) for Tropical Cyclone Vince was 20.6.  The Hurricane Size Index (HSI) was 13.7 and the Hurricane Wind Intensity Size Index (HWISI) was 34.3.  Tropical Cyclone Vince was similar in size and intensity to Hurricane Delta when Delta hit Southwest Louisiana in 2020.

Tropical Cyclone Vince will move through an environment favorable for intensification 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 moderate vertical wind shear.  Even though Tropical Cyclone Vince will move through an environment favorable for intensification during the next 24 hours, Vince is likely to weaken due to the effects of the eyewall replacement cycle.

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 pass far to the south of Diego Garcia later this week.

Elsewhere, Tropical Cyclone Taliah intensified as it moved farther away from Western Australia.  At 4:00 a.m. EST on Tuesday the center of Tropical Cyclone Taliah was located at latitude 15.6°S and longitude 110.4°E which put the center about 515 miles (830 km) north-northwest of Exmouth, Australia.  Taliah was moving toward the west at 15 m.p.h. (24 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 972 mb.

Tropical Cyclone Sean Rapidly Intensifies to Equivalent of Major Hurricane

Tropical Cyclone Sean rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean west of Australia on Monday.  At 10:00 a.m. EST on Monday the center of Tropical Cyclone Sean was located at latitude 23.0°S and longitude 110.4°E which put the center about 210 miles (340 km) west of Exmouth, Australia.  Sean was moving toward the southwest at 13 m.p.h. (21 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 936 mb.

A Warning was in effect for the portion of the coast from Onslow to Ningaloo.  The Warning included Exmouth.

Tropical Cyclone Sean rapidly intensified to the equivalent of a major hurricane west of Australia on Monday.  A small circular eye with a diameter of 10 miles (16 km) was at the center of Sean’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Sean.  Storms near the core of Sean 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 Sean was relatively small.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 110 miles (175 km) from the center of Tropical Cyclone Sean.

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

Tropical Cyclone Sean will move through an environment that will become unfavorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 27°C.  It will move under the eastern part of an upper level trough over the South Indian Ocean.  The upper level trough will produce northwesterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause the vertical wind shear to increase.  The combination of cooler water and  more vertical wind shear will cause Tropical Cyclone Sean to weaken during the next 24 hours.

Tropical Cyclone Sean will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Sean toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move a little farther away from the coast of Western Australia.

Bands in the eastern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause floods in some locations.  10.78 inches (274 mm) of rain has already fallen at the Karratha Airport.  4.37 inches (111 mm) of rain has already fallen at the Mardie Airport.

Flood Warnings were in effect for parts of the Pilbara and northern Gascoyne regions.  A Flood Warning was in effect for the Lyndon-Minilya Rivers. 

 

Tropical Cyclone Dikeledi Passes Southwest of Madagascar

Tropical Cyclone Dikeledi passed southwest of Madagascar on Wednesday.  At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Dikeledi was located at latitude 26.4°S and longitude 42.9°E which put the center about 150 miles (240 km) southwest of Beloha, Madagascar.  Dikeledi was moving toward the south-southeast at 22 m.p.h. (35 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 963 mb.

Tropical Cyclone Dikeledi intensified on Wednesday as it moved southwest of Madagascar.  A circular eye with a diameter of 25 miles (40 km) formed at the center of Dikeledi’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Dikeledi.  Storms near the core of Dikeledi 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 Dikeledi increased on Wednesday.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Dikeledi’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) in the eastern side of Tropical Cyclone Dikeledi.  Winds to tropical storm force only extended out 60 miles (95 km) in the western side of Dikeledi.

The Hurricane Intensity Index (HII) for Tropical Cyclone Dikeledi was 16.5.  The Hurricane Size Index (HSI) was 11.8 and the Hurricane Wind intensity Size INdex (HWISI) was 28.3.  Tropical Cyclone Dikeledi was similar in size and intensity to Hurricane Idalia when Idalia hit Florida in 2023.

Bands in the eastern side of Tropical Cyclone Dikeledi were bring gusty winds and heavy rain to southern Madagascar.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Dikeledi will move through an environment that will become unfavorable for intensification during the next 24 hours.  Dikeledi will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the eastern side of an upper level trough over southern Africa.  The upper level trough will produce northwesterly winds that will blow toward the top of Dikeledi’s circulation.  Those winds will cause the vertical wind shear to increase.  Tropical Cyclone Dikeledi will weaken when the wind shear increases.

The upper level trough over southern Africa will steer Tropical Cyclone Dikeledi toward the southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Dikeldi will pass south of Madagascar.  Dikeledi will move southeast of Madagascar on Thursday.

Tropical Cyclone Dikeledi Hits Northern Mozambique

Tropical Cyclone Dikeledi hit northern Mozambique on Monday morning.  At 7:00 a.m. EST on Monday the center of Tropical Cyclone Dikeledi was located at latitude 15.1°S and longitude 40.6°E which put the center about 30 miles (50 km) south of Nacala, Mozambique.  Dikeledi was moving toward the west-southwest at 18 m.p.h. (30 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 982 mb.

Tropical Cyclone Dikeledi hit the coast of northern Mozambique just to the south of Nacala on Monday morning.  Dikeledi was the equivalent of a hurricane/typhoon at the time the center made landfall.  A small circular eye was present at the center of Dikeledi’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 Tropical Cyclone Dikeledi.

The circulation around Tropical Cyclone Dikeledi was relatively small.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Dikeledi’s circulation. Winds to tropical storm force extended out 70 miles (110 km) from the center of Tropical Cyclone Dikeledi.

The Hurricane Intensity Index (HII) for Tropical Cyclone Dikeledi is 11.5.  The Hurricane Size Index (HSI) is 8.5 and the Hurricane Wind Intensity Size Index (HWISI) is 20.0.  Tropical Cyclone Dikeledi is similar in size to Hurricane Isaias when Isaias hit North Carolina in 2020.  Dikeledi is not as strong as Isaias was.

Tropical Cyclone Dikeledi will move around the western end of a high pressure system over the South Indian Ocean.  The high pressure system will steer Dikeledi toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Dikeledi will move along the coast of northern Mozambique during the next 24hours.

The center of Tropical Cyclone Dikeledi will be just inland along the coast of northern Mozambique south of Nacala during the next 24 hours.  Dikeledi will bring strong winds and heavy rain to the coast of Mozambique.  Heavy rain is likely to cause flash floods in some locations.  Dikeledi could cause a storm surge of up to 7 feet (2 meters) along the coast of northern Mozambique.  Tropical Cyclone Dikeledi could move back over the Mozambique Channel later this week.