Category Archives: Indian Ocean

Tropical Cyclone Herold Passes North of Mauritius

Tropical Cyclone Herold passed north of Mauritius on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Cyclone Herold was located at latitude 17.3°S and longitude 57.6°E which put it about 230 miles (370 km) north of Port Louis, Mauritius.  Herold was moving toward the east-southeast at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 972 mb.

The circulation around Tropical Cyclone Herold remained well organized on Monday.  Microwave satellite imagery indicated that there was an eye at the center of circulation, but the eye was not visible on conventional satellite images.  The eye was surround by a narrow 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 Herold.  Many of the stronger thunderstorms were in bands south and east of the center of circulation.  Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center.  Winds to tropical storm force extended out 130 miles (215 km) from the center of circulation.

Tropical Cyclone Herold may have reached its maximum intensity.  Herold will move over water where the Sea Surface Temperature is near 28°C.  So, there will be plenty of energy in the upper layer of the South Indian Ocean to support intensification.  However, an upper level trough near Madagascar and an upper level ridge over the South Indian Ocean will interact to produce strong northwesterly winds which will blow toward the top of Tropical Cyclone Herold.  Those winds will cause moderate vertical wind shear and they will likely prevent further intensification.  In fact the wind shear is likely to be strong enough to cause Herold to start to weaken during the next 24 hours.

The upper level trough and ridge will combine to steer Tropical Cyclone Herold quickly toward the east-southeast.  On its anticipated track Herold could reach Rodrigues within 24 hours.  Tropical Cyclone Herold is likely to bring gusty winds and locally heavy rain to Port Mathurin and the rest of Rodrigues.  Heavy rain could cause flash floods in some locations.

Tropical Cyclone Gretel Speeds By New Caledonia

Tropical Cyclone Gretel sped by New Caledonia on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone Gretel was located at latitude 25.9°S and longitude 169.4°E which put it about 750 miles (1210 km) north-northwest of Auckland, New Zealand.  Gretel was moving toward the southeast at 37 m.p.h. (60 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 Gretel moved around the western end of high pressure system over the South Pacific Ocean.  The high steered Gretel rapidly toward the southeast and the tropical cyclone sped over the Coral Sea west of New Caledonia.  Rainbands on the eastern side of Tropical Cyclone Gretel brought wind and rain to portions of New Caledonia on Sunday.

An upper level ridge produced strong northwesterly winds which created strong vertical wind shear.  The wind shear tilted the circulation around Tropical Cyclone Gretel toward the southeast and Gretel began to weaken.  The stronger thunderstorms were occurring in bands south and east of the center of Gretel.  Bands in other parts of the tropical cyclone consisted primarily of showers and lower clouds.  The wind field around Gretel expanded when the tropical cyclone started to weaken.  Winds to tropical storm force extended out 250 miles (400 km) from the center of circulation.

Tropical Cyclone Gretel will continue to move rapidly toward the southeast during the next several days.  On its anticipated track Gretel could pass north of New Zealand in 24 to 36 hours.

Elsewhere, over the South Indian Ocean Tropical Cyclone Herold strengthened east of Madagascar.  At 5:00 p.m EDT on Sunday the center of Tropical Cyclone Herold was located at latitude 15.5°S and longitude 53.2°E which put it about 405 miles (655 km) west-northwest of Port Louis, Mauritius.  Herold was moving toward the east-southeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 972 mb.  Tropical Cyclone Herold could reach Rodrigues in about 48 hours.

Tropical Cyclone Herold Drops Heavy Rain Over Northeast Madagascar

Tropical Cyclone Herold dropped heavy rain over parts of northeast Madagascar on Saturday.  A rainband on the western side of Herold was dropping locally heavy rain over northern Madagascar from Mananara to Iharana.  At 5:00 p.m. EST on Saturday the center of Tropical Cyclone Herold was located at latitude 15.0°S and longitude 51.2°E which put it about 545 miles (880 km) northwest of Port Louis, Mauritius.  Herold was moving toward the east at 1 m.p.h. (2 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 981 mb.

Tropical Cyclone Herold strengthened into the equivalent of a hurricane/typhoon on Saturday.  A large ragged circular eye with a diameter of 50 miles (80 km) formed at the center of Herold.  A broken ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  One strong band of showers and thunderstorms wrapped around the eastern and southern sides of Tropical Cyclone Herold.  A second strong band of showers and thunderstorms wrapped around the western and northern sides of Herold.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 85 miles from the center.

Tropical Cyclone Herold will move through an environment favorable for intensification during the next 48 hours.  Herold will move over water where the Sea Surface Temperature is near 29°C.  It will move under an upper level ridge where the winds are weak and there will be little vertical wind shear.  Tropical Cyclone Herold will intensify during the next 48 hours and it could strengthen into the equivalent of a major hurricane.

Tropical Cyclone Herold has been in an area where the steering winds are weak and it has not moved very far during the past 24 hours.  A subtropical high pressure system over the South Indian Ocean will strengthen.  Herold will move around the southwestern part of the high pressure system and the high will steer the tropical cyclone toward the east-southeast.  On its anticipated track Tropical Cyclone Herold will move away from Madagascar on Sunday.  The center of Herold could pass north of Mauritius in three days.  Tropical Cyclone Herold could approach Rodrigues in 84 to 90 hours.

Tropical Cyclone Herold Forms East of Madagascar

Tropical Cyclone Herold formed over the South Indian Ocean east of Madagascar on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Herold was located at latitude 14.8°S and longitude 51.9°E which put it about 510 miles (825 km) northwest of Port Louis, Mauritius.  Herold was moving toward the southwest at 4 m.p.h. (6 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 996 mb.

A distinct low level center of circulation organized quickly in an area of thunderstorms east of Madagascar on Friday and the system was designated as Tropical Cyclone Herold.  The circulation around Herold was still organizing and the distribution of thunderstorms was asymmetrical.  Many of the stronger thunderstorms developed in bands northwest of the center of circulation.  Bands in other parts of the circulation consisted primarily of showers and lower clouds.  Thunderstorms northwest of the center of Herold were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation.

Tropical Cyclone Herold will move through an environment that will become increasingly favorable for intensification during the next several days.  Herold is currently under a small upper level ridge centered near Madagascar.  The ridge is producing southeasterly winds which are blowing toward the top of the circulation.  Those winds are causing some vertical wind shear and they are probably the reason for the asymmetrical distribution of thunderstorms.  However, Tropical Cyclone Herold will move into a region where the upper level winds are weaker during the weekend.  Herold will move over water where the Sea Surface Temperature is near 29°C during that time period.  Tropical Cyclone Herold will intensify during the next several days and it could intensify rapidly once the inner core becomes better organized.  Herold is likely to intensify into the equivalent of a hurricane/typhoon during the next 24 hours.  It could strengthen into the equivalent of a major hurricane during the next 72 hours.

Tropical Cyclone Herold is currently in an area where the steering currents are weak.  A subtropical high pressure system over the South Indian Ocean will strengthen during the next several days.  The western end of the subtropical high will start to steer Herold toward the east-southeast during the weekend.  On its anticipated track the center of Tropical Cyclone Herold could be northwest of Mauritius in less than 72 hours.  Herold is likely to be the equivalent of a major hurricane at that time.

Former Tropical Cyclone Esther Drops Heavy Rain Over Northwestern Australia

Former Tropical Cyclone Esther dropped heavy rain over parts of northwestern Australia on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Esther was located at latitude 15.3°S and longitude 130.8°E which put it about 240 miles (390 km) south of Darwin, Australia.  Esther was moving toward the west at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 996 mb.

The circulation around former Tropical Cyclone Esther remained very well organized on Wednesday even though it had been moving across northern Australia for several days.  There was a distinct low level center of circulation.  The circulation was surrounded by bands of showers and thunderstorms.  Strong thunderstorms developed south of Darwin in a band in the northern part of the circulation.  The Darwin harbor reported a wind gust of 44 m.p.h. (72 km/h).  The Wyndham airport reported a wind gust of 39 m.p.h. (63 km/h).

Former Tropical Cyclone Esther could strengthen back into a tropical cyclone if the center of circulation moves over the South Indian Ocean west of Australia.  Esther will move through an environment favorable for intensification during the next day or two.  The Sea Surface Temperature near the west coast of Australia is near 30°C.  Esther will move under an upper level ridge where the winds are weak and there is little vertical wind shear.  Former Tropical Cyclone Esther could intensify rapidly if the center of circulation moves completely over water.

Former Tropical Cyclone Esther will move around the western end of a high pressure system over Australia during the next several days.  The high will steer Esther toward the west during the next 24 to 48 hours.  It will turn more toward the south when it reaches the western end of the high pressure system.  On its anticipated track the center of former Tropical Cyclone Esther will pass near the southern end of the Joseph Bonaparte Gulf.

Elsewhere over the South Indian Ocean, Tropical Cyclone Ferdinand churned northwest of Australia.  At 10:00 p.m. EST the center of Tropical Cyclone Ferdinand was located at latitude 16.6°S and longitude 114.3°E which put it about 400 miles (645 km) north of Learmonth, Australia.  Ferdinand was moving toward the west at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 966 mb.

Tropical Cyclone Esther Makes Landfall in Northern Australia

Tropical Cyclone Esther made landfall in northern Australia just to the east of the border between Queensland and the Northern Territory on Sunday night.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Esther was located at latitude 16.7°S and longitude 137.9°E which put it about 65 miles (105 km) west of Mornington Island.  Esther was moving toward the west-southwest at 10 m.p.h. (16 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 988 mb.

A Warning remained in effect for the portion of the coast from Port McArthur to Karumba, Australia including Borroloola and Mornington Island.

Tropical Cyclone Esther was intensifying slowly when it made landfall just east of the border between Queensland and the Northern Territory of Australia.  Winds to tropical storm force extended out 75 miles (120 km) from the center of circulation.  A weather station at Mornington Island reported a sustained wind speed of 35 m.p.h. (57 km/h) and a wind gust of 54 m.p.h. (87 km/h).  The station measured 6.77 inches (172 mm) of rain.

Tropical Cyclone Esther will weaken as it moves inland.  Esther will move north of a high pressure system over Australia.  The high will steer Tropical Cyclone Esther toward the west during the next few days.  On its anticipated track Esther will move across the Northern Territory.  Tropical Cyclone Esther will drop locally heavy rain and it could cause flash floods in some locations.  There is a potential for Esther to strengthen again in a few days when it moves over the South Indian Ocean northwest of Australia.

Elsewhere, Tropical Cyclone Ferdinand developed over the South Indian Ocean northwest of Australia.  At 4:00 p.m. EST on Sunday the center of Tropical Storm Ferdinand was located at latitude 13.8°S and longitude 117.8°E which put it about 450 miles (750 km) north of Port Hedland, Australia.  Ferdinand was moving toward the southwest at 7 m.p.h. (11 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 993 mb.  Tropical Cyclone Ferdinand is forecast to move toward the west-southwest and to strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Gabekile Develops South of Diego Garcia

Tropical Cyclone Gabekile developed south of Diego Garcia on Saturday.  At 10:00 a.m. EST on Saturday the center of Tropical Cyclone Gabekile was located at latitude 17.4°S and longitude 74.1°E which put it about 700 miles (1125 km) south of Diego Garcia.  Gabekile was moving toward the south-southwest at 5 m.p.h. (8 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 995 mb.

The circulation around Tropical Cyclone Gabekile was small but well organized.  Some microwave images suggested that a small eye could be forming at the center of circulation.  The eyelike feature was surrounded by a tight ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the small core of Gabekile.  Storms near the core generated upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out 65 miles (105 km) from the center of circulation.

Tropical Cyclone Gabekile will move through an environment favorable for intensification during the next several days.  Gabekile will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge over the South Indian Ocean.  The ridge will produce northerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Gabekile could strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Gabekile will move around the western end of a high pressure system over the South Indian Ocean.  The high will steer Gabekile  toward the south.  On its anticipated track Tropical Cyclone Gabekile will move farther away from Diego Garcia.

Elsewhere over the South Indian Ocean, Tropical Cyclone Francisco was weakening as it moved slowly inland over east-central Madagascar.  At 7:00 a.m. EST on Saturday the center of Tropical Cyclone Francisco was located at latitude 20.0°S and longitude 48.3°E which put it about 10 miles (15 km) north of Marolambo, Madagascar.  Francisco was moving toward the southwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.  Tropical Cyclone Francisco was dropping locally heavy rain over parts of Madagascar.

Tropical Cyclone Francisco Redevelops Near East Coast of Madagascar

After moving slowly westward across the Southwest Indian Ocean for the past few days, Tropical Cyclone Francisco redeveloped near the east coast of Madagascar on Thursday.  At 7:00 a.m. EST on Thursday the center of Tropical Cyclone Francisco was located at latitude 17.9°S and longitude 50.7°E which put it about 90 miles (145 km) east of Toamasina, Madagascar.  Francisco was moving toward the west at 6 m.p.h. (9 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 1004 mb.

Strong vertical wind shear weakened Tropical Cyclone Francisco east of Rodrigues last Thursday, but the lower portion of the circulation remained intact.  The lower level circulation drifted slowly westward during the last seven days and it moved across Mauritius and La Reunion earlier the week.  More thunderstorms began to develop around the lower level circulation on Wednesday, when it moved closer to the east coast of Madagascar.  Bands of showers and thunderstorms began to reform.  Storms near the center of circulation started generating upper level divergence which pumped mass away from the tropical cyclone.  The removal of mass allowed the surface pressure to decrease and the wind speeds began to increase.

Tropical Cyclone Francisco has exhibited greater organization in recent hours.  However, the distribution of thunderstorms was asymmetrical.  Many of the stronger thunderstorms were occurring in bands in the western half of the circulation.  Bands in the eastern half of the circulation consisted primarily of showers and lower clouds.  Francisco was moving under the northern part of an upper level ridge.  The ridge was producing easterly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical wind shear and the shear could be responsible for the asymmetrical distribution of thunderstorms.

Tropical Cyclone Francisco will move through an environment favorable for intensification during the next 6 to 12 hours.  Francisco will move over water where the Sea Surface Temperature is near 28°C.  The upper level ridge will still cause vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Francisco will weaken when it moves over Madagascar.

Tropical Cyclone Francisco will move north of a high pressure system over the Southwest Indian Ocean.  The high will steer Francisco toward the west.  On its anticipated track Tropical Cyclone Francisco could make landfall on the east coast of Madagascar in about 12 hours.  Francisco will drop locally heavy rain over parts of central Madagascar.  The heavy rain could cause flash floods in some locations,

Tropical Cyclone Damien Brings Wind and Rain to Western Australia

Tropical Cyclone Damien brought wind and rain to Western Australia on Saturday.  At 10:00 a.m. EST on Saturday the center of Tropical Cyclone Damien was located at latitude 21.7°S and longitude 117.0°E which put it about 60 miles (100 km) south-southeast of Karratha, Australia.  Damien was moving toward the south-southeast at 10 m.p.h. (16 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 962 mb.

A Warning was in effect for the portion of the coast of Western Australia from Whim Creek to Mardie including Karratha and Dampier.  Flood Warnings were in effect for the Fortescue River and the Coastal Pilbara Rivers.  A Flood Watch was in effect for the Pilbara and Gascoyne District.  An Initial Flood Warning was issued for the Ashburton River.

A weather station at Karratha reported a sustained wind speed of 90 m.p.h. (145 km/h or 78 kt) when the core of Tropical Cyclone Damien passed over it.  The station also reported a wind gust of 114 m.p.h. (183 km/h or 99 kt).  The weather station at Karratha measured 6.14 inches (156 mm) of rain during the passage of Damien.  The minimum pressure was 957 mb.

Tropical Cyclone Damien will move around the western end of a high pressure system over Australia.  The high will steer Damien toward the south-southeast during the next several days.  On its anticipated track Tropical Cyclone Damien could approach Tom Price and Paraburdoo in about 12 hours.  Damien will weaken slowly as it moves farther inland.  It will continue to produce strong winds capable of causing damage during the next 12 to 24 hours  Tropical Cyclone Damien could also drop locally heavy rain over parts of Western Australia during the next several days.

Strengthening Tropical Cyclone Damien Nears Western Australia

Strengthening Tropical Cyclone Damien neared the coast of Western Australia on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Damien was located at latitude 19.4°S and longitude 116.6°E which put it about 100 miles (160 km) north-northwest of Karratha, Australia.  Damien was moving toward the south-southwest at 7 m.p.h. (11 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.

A Warning was in effect for the portion of the coast of Western Australia from De Grey to Onslow including Dampier, Karratha and Port Hedland.  Initial Flood Warnings were in effect for the Coastal Pilbara Rivers.  A Flood Watch was in effect for the Pilbara and Gascoyne District.

Tropical Cyclone Damien continued to strengthen quickly on Friday.  A circular eye developed at the center of Damien.  A narrow ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Damien.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Damien was relatively small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Damien was 16.5.  The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 26.4.  Damien was capable of causing localized serious damage.

Tropical Cyclone Damien will move through an environment favorable for intensification during the next 12 hours.  Damien will move over water where the Sea Surface Temperature is near 30°C.  It will move under the western end of an upper level ridge over Australia.  The ridge will produce northerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent Tropical Cyclone Damien from strengthening.  Damien could intensify into the equivalent of a major hurricane before it reaches the coast of Western Australia.

Tropical Cyclone Damien will move around the western end of a high pressure system over Australia.  The high will steer Damien toward the south during the next several days.  On its anticipated track the center of Tropical Cyclone Damien could make landfall on the coast of Western Australia near Dampier and Karratha in about 12 hours.  Damien will be capable of causing serious wind damage.  It will also produce a storm surge of up to 10 feet (3 meters) between Port Hedland and Dampier where the wind blows the water toward the coast.  The highest storm surge will occur near where the center makes landfall.  Tropical Cyclone Damien will also drop locally heavy rain and flash floods could occur in parts of Western Australia.