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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.

Tropical Cyclone Nat Moves Southwest of Tahiti

Tropical Cyclone Nat moved southwest of Tahiti on Wednesday. At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Nat was located at latitude 19.5°S and longitude 151.2°W which put it about 185 miles (300 km) southwest of Papeete, Tahiti. Nat was moving toward the southeast 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 998 mb.

Tropical Cyclone Nat brought rain showers and gusty winds to Tahiti on Wednesday. Nat started to weaken as it moved southwest of Tahiti. An upper level trough northeast of New Zealand produced strong westerly winds that blew across the top of Nat’s circulation. Those winds cause strong vertical wind shear. The strong upper level winds blew away the tops of many of the thunderstorms in Tropical Cyclone Nat. A few thunderstorms persisted in a band in the far eastern edge of Nat’s circulation. Other bands revolving around the center of Tropical Cyclone Nat consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 75 miles (120 km) from the center of Nat’s circulation.

Tropical Cyclone Nat will move through an environment unfavorable for intensification during the next 24 hours. Nat will move over water where the Sea Surface Temperatures are near 29°C. However, the upper level trough northeast of New Zealand will continue to cause strong vertical wind shear. The strong vertical wind shear will cause Tropical Cyclone Nat to continue to weaken during the next 24 hours.

The upper level trough northeast of New Zealand will steer Tropical Cyclone Nat toward the east during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Nat will pass south of Tahiti. Bands in the northern side of Nat will continue to bring gusty winds and rain showers to Tahiti during the next 24 hours.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Osai strengthened west of Palmerston Island. At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Osai was located at latitude 18.1°S and longitude 164.4°W which put it about 85 miles (135 km) west of Palmerston Island. Osai was moving toward the southeast at 18 m.p.h. (29 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 993 mb.

Tropical Cyclone Nat Moves Toward Tahiti

Tropical Cyclone Nat moved toward Tahiti on Tuesday. At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone Nat was located at latitude 17.6°S and longitude 155.4°W which put it about 415 miles (670 km) west of Pappete, Tahiti. Nat was moving toward the east-southeast at 20 m.p.h. (32 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 993 mb.

Tropical Cyclone Nat strengthened a little as it moved over the South Pacific Ocean toward Tahiti on Tuesday. Thunderstorms continued to form near the center of Nat’s circulation. Storms near the center of circulation generated upper level divergence that pumped mass away to the east of the tropical cyclone. Thunderstorms were also occurring in bands in the northern and eastern parts of Tropical Cyclone Nat. Bands in the western and southern part of Nat’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extend out 120 miles (195 km) in the northwest, northeast and southeast quadrants of Tropical Cyclone Nat. Winds to tropical storm force only extended out 40 miles (65 km) in the southwest quadrant of Nat.

Tropical Cyclone Nat will move through an environment unfavorable for intensification during the next 24 hours. Nat will move over water where the Sea Surface Temperatures are near 29°C. It will move under the eastern side of an upper level trough over the South Pacific Ocean northeast of New Zealand. The upper level trough will produce strong northwesterly winds that will blow toward the top of Nat’s circulation. Those winds will cause strong vertical wind shear. The strong vertical wind shear is likely to cause Tropical Cyclone Nat to start to weaken during the next 24 hours.

The upper level trough northeast of New Zealand will steer Tropical Cyclone Nat toward the east-southeast during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Nat will pass south of Bora Bora during the next 24 hours. Nat could be near Tahiti within 36 hours. Bands in the northern side of Nat could bring gusty winds and locally heavy rain to the Society Islands. Heavy rain could cause flash floods in some locations.

Elsewhere over the South Pacific Ocean, Tropical Cyclone 11P formed north of American Samoa. At 4:00 p.m. EST on Tuesday the center of Tropical Cyclone 11P was located at latitude 13.3°S and longitude 168.9°W which put it about 110 miles (195 km) north of Pago Pago, American Samoa. The tropical cyclone was moving toward the southeast at 21 m.p.h. (33 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 997 mb. Heavy rain could cause flash floods in parts of American Samoa.

Tropical Cyclone Nat Forms West of Tahiti

Tropical Cyclone Nat formed over the South Pacific Ocean west of Tahiti on Monday. At 1:00 p.m. EST on Monday the center of Tropical Cyclone Nat was located at latitude 15.3°S and longitude 163.6°W which put it about 965 miles (1560 km) west of Pappete, Tahiti. Nat was moving toward the east-southeast at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 996 mb.

A low pressure system over the South Pacific Ocean between Samoa and Tahiti strengthened on Monday and the Fiji Meteorological Service designated the system as Tropical Cyclone Nat. More thunderstorms formed near the center of Tropical Cyclone Nat. Storms near the center of Nat’s circulation generated upper level divergence that pumped mass away to the east of the tropical cyclone. Thunderstorms were also occurring in bands in the northern and eastern parts of Tropical Cyclone Nat. Bands in the western and southern part of Nat’s circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extend out 160 miles (260 km) in the northwest, northeast and southeast quadrants of Tropical Cyclone Nat. Winds to tropical storm force only extended out 25 miles (40 km) in the southwest quadrant of Nat.

Tropical Cyclone Nat will move through an environment somewhat favorable for intensification during the next 24 hours. Nat will move over water where the Sea Surface Temperatures are near 30°C. It will move under the eastern side of an upper level trough over the South Pacific Ocean northeast of New Zealand. The upper level trough will produce northwesterly winds that will blow toward the top of Nat’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but the shear may not be strong enough to prevent intensification. Tropical Cyclone Nat could intensify gradually during the next 24 hours.

The upper level trough northeast of New Zealand will steer Tropical Cyclone Nat toward the east-southeast during the next 24 hours. On its anticipated track, Nat will move closer to Tahiti. The center of Tropical Cyclone Nat is forecast to pass north of Palmerston, Aitutaki and Mauke. The winds blowing around the southern side of Nat’s could bring gusty winds and rough seas to those places during the next 24 hours.

Tropical Cyclone Eloise nears Northern Madagascar

Tropical Cyclone Eloise neared northern Madagascar on Monday. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Eloise was located at latitude 14.3°S and longitude 52.0°E which put it about 125 miles (200 km) east of Antalaha, Madagascar. Eloise was moving toward the west at 23 m.p.h. (37 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 983 mb.

Tropical Cyclone Eloise strengthened as it quickly neared northern Madagascar on Sunday. The inner end of a rainband wrapped around the center of Eloise. More thunderstorms formed in bands revolving around the center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical cyclone. The circulation became more symmetrical. Winds to tropical storm force extended out 125 miles (200 km) from the center of circulation.

Tropical Cyclone Eloise will move through an environment somewhat favorable for intensification during the next few hours before it reaches northern Madagascar. Eloise will move over water where the Sea Surface Temperature is near 28°C. It will move under the northern portion of an upper level ridge over the South Indian Ocean. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause some vertical wind shear which will inhibit intensification. Tropical Cyclone Eloise could intensify until it moves over Madagascar.

Tropical Cyclone Eloise will move north of a high pressure system over the South Indian Ocean. The high will steer Eloise toward the west-southwest during the next 48 hours. On its anticipated track Tropical Cyclone Eloise could make landfall on the northeastern coast of Madagascar near Antahala in a few hours. Eloise will produce gusty winds and heavy rain over northern Madagascar. Heavy rain could cause flash floods in some locations.

Elsewhere over the South Indian Ocean, Tropical Cyclone Joshua moved far to the southeast of Diego Garcia. At 11:00 a.m. EST on Monday the center of Tropical Cyclone Joshua was located at latitude 19.8°S and longitude 87.5°E which put it about 1335 miles (2150 km) southeast of Diego Garcia. Joshua was moving toward the southwest at 9 m.p.h. (15 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 994 mb.

Tropical Cyclone Eloise Develops Northeast of Mauritius

Tropical Cyclone Eloise developed northeast of Mauritius on Sunday. At 4:00 a.m. EST on Sunday the center of Tropical Cyclone Eloise was located at latitude 12.7°S and longitude 61.5°E which put it about 605 miles (980 km) north-northeast of Port Louis, Mauritius. Eloise was moving toward the west at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 995 mb.

The circulation around a low pressure system northeast of Mauritius strengthened on Sunday morning and the system was designated as Tropical Cyclone Eloise. The distribution of thunderstorms around Eloise was asymmetrical. The strongest thunderstorms were occurring in bands in the western half of Tropical Cyclone Eloise. Bands in the eastern half of the circulation consisted primarily of showers and lower clouds. Storms near the center of Eloise generated upper level divergence which pumped mass away to the west of the tropical cyclone. Winds to tropical storm force extended out 75 miles (120 km from the center of circulation.

Tropical Cyclone Eloise will move through an environment somewhat favorable for intensification during the next several days. Eloise will move over water where the Sea Surface Temperature is near 28°C. It will move under the northern portion of an upper level ridge over the South Indian Ocean. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause moderate vertical wind shear which will inhibit intensification. Tropical Cyclone Eloise could intensify slowly during the next 24 hours despite the moderate vertical wind shear.

Tropical Cyclone Eloise will move north of a high pressure system over the South Indian Ocean. The high will steer Eloise toward the west during the next several days. On its anticipated track Tropical Cyclone Eloise could approach northern Madagascar in about three days.

Elsewhere over the South Indian Ocean, Tropical Cyclone Joshua moved far to the southeast of Diego Garcia. At 4:00 a.m. EST on Sunday the center of Tropical Cyclone Joshua was located at latitude 18.5°S and longitude 89.8°E which put it about 1405 miles (2265 km) southeast of Digeo Garcia. Joshua was moving toward the southwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 997 mb.