Tag Archives: Tropical Cyclone Sean

Tropical Cyclone Sean Continues to Weaken

Tropical Cyclone Sean continued to weaken steadily on Wednesday.  At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Sean was located at latitude 28.5°S and longitude 107.4°E which put the center about 440 miles (740 km) west of Geraldton, Australia.  Sean was moving toward the south-southeast 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 992 mb.

The effects of cooler Sea Surface Temperatures and strong vertical wind shear caused Tropical Cyclone Sean to continue to weaken on Wednesday.  An upper level trough over the South Indian Ocean west of Australia was producing strong northwesterly winds that were blowing across the top of Sean’s circulation.  Those winds were causing strong vertical wind shear.  The strong upper level winds also blew the tops off of thunderstorms that had been in the southeastern part of Tropical Cyclone Sean.  Bands revolving around the center of Sean’s circulation consisted primarily of showers and lower clouds.

Winds to tropical storm force extended out 130 miles (210 km) from the center of Tropical Cyclone Sean.

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

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

Tropical Cyclone Sean Weakens

Tropical Cyclone Sean weakened over the South Indian Ocean west of Australia on Tuesday.  At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Sean was located at latitude 26.7°S and longitude 107.3°E which put the center about 380 miles (610 km) west of Carnarvon, Australia.  Sean was moving toward the south-southwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 977 mb.

Tropical Cyclone Sean weakened on Tuesday as it moved over cooler water in the South Indian Ocean west of Australia.  An eye was no longer visible in the center of Sean’s circulation.  Thunderstorms were still occurring in bands in the southern and eastern parts of Tropical Cyclone Sean.  Bands in the northern and western parts of Sean’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Sean still produced some upper level divergence that pumped mass away to the southeast of the tropical cyclone.  The removal of mass in the upper levels of the atmosphere was less than the inflow of mass in the lower levels, which caused the surface pressure to increase.

The size of the circulation around Tropical Cyclone Sean increased even though Sean was weakening.  Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center of Tropical Cyclone Sean.

Tropical Cyclone Sean will move through an environment that will be unfavorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 24°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 moderate vertical wind shear.  The combination of cooler water and moderate vertical wind shear will cause Tropical Cyclone Sean to continue to weaken during the next 24 hours.

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

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 Sean Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Sean intensified to the equivalent of a hurricane/typhoon near the coast of Western Australia on Sunday.  At 10:00 a.m. EST on Sunday the center of Tropical Cyclone Sean was located at latitude 20.5°S and longitude 113.9°E which put the center about 125 miles (200 km) north of Exmouth, Australia.   Sean was moving toward the west-southwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).   The minimum surface pressure was 978 mb.

A Warning was in effect for the portion of the coast from Whim Creek to Ningaloo.  The Warning included Karratha, Damoier, Onslow, and Exmouth.

Tropical Cyclone Sea intensified to the equivalent of a hurricane/typhoon near the coast of Western Australia on Sunday.  A circular eye with a diameter of 17 miles (28 km) formed 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 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 Sean was relatively small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Sean’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Cyclone Sean.

Tropical Cyclone Sean will move through an environment favorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the northern part of an upper level ridge northwest of Australia.  The upper level ridge will produce easterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Cyclone Sean will intensify 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 west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.  The center of Sean is forecast to remain over water.

Bands in the southern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause flash floods in some locations.  3.74 inches (95 mm) of rain fell at the Lombadina Airstrip.

A Flood Watch was in effect for the coastal parts of the Kimberley and the Pilbara Districts.  Catchments likely to be affected include the West Kimberley Rivers, the De Grey River, the Pilbara Coastal Rivers, the Fortescue River, the Onslow Coast, and the Lyndon-Minilya Rivers.

Tropical Cyclone Sean Strengthens Near Western Australia

Tropical Cyclone Sean strengthened near the coast of Western Australia on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Sean was located at latitude 19.7°S and longitude 115.7°E which put the center about 120 miles (195 km) northwest of Karratha, Australia.  Sean was moving toward the west-southwest at 14 m.p.h. (22 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 987 mb.

A Warning was in effect for the portion of the coast from Whim Creek to Ningaloo.  The Warning included Karratha, Damoier, Onslow, and Exmouth.

A former Tropical Low near the coast of Western Australia strengthened on Saturday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Sean.  The inner end of a rainband wrapped around the western side of the center of Tropical Cyclone Sean.  A circular eye appeared to be forming at the center of Sean’s circulation.  Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Sean.  Storms near the center of Sean generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass allowed the surface pressure to decrease.

The distribution of wind speeds around Tropical Cyclone Sean was relatively symmetrical.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Sean’s circulation.

Tropical Cyclone Sean will move through an environment favorable for intensification during the next 24 hours.  Sean will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the northern part of an upper level ridge northwest of Australia. The upper level ridge will produce easterly winds are that will blow toward the top of Sean’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Cyclone Sean will to intensify during the next 24 hours.  Sean could strengthen to the equivalent of a hurricane/typhoon.

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 west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.  The center of Sean is forecast to remain over water.

Bands in the southern side of Tropical Cyclone Sea will bring gusty winds and locally heavy rain to the coast of Western Australia.  Heavy rain could cause flash floods in some locations.