Category Archives: Indian Ocean

Tropical Depression Forms East of Sri Lanka

A Tropical Depression (also designated as Invest 98B) formed over the southern Bay of Bengal east of Sri Lanka on Monday. At 10:00 p.m. EST on Monday the center of a tropical depression was located at latitude 6.7°N and longitude 86.3°E which put it about 295 miles (475 km) east of Pottuvil, Sri Lanka. It 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 45 m.p.h. (75 km/h). The minimum surface pressure was 1004 mb.

A low level center of circulation developed in an area of thunderstorms over the southern Bay of Bengal east of Sri Lanka on Monday. The circulation around the tropical depression was still organizing on Monday night. More thunderstorms were developing near the low level center. Bands of showers and thunderstorms were forming outside the center of circulation. Storms near the center started to generate upper level divergence which pumped mass away to the north and west of the tropical depression.

The tropical depression will move through a region somewhat favorable for intensification during the next 24 hours. The depression will move over water where the Sea Surface Temperature is near 29°C. It will move under the western end of an upper level ridge centered over Southeast Asia. The ridge will produce easterly winds which will blow toward the top of the depression. Those winds will cause moderate vertical wind shear. The shear will inhibit intensification, but it probably will not be strong enough to prevent the tropical depression from intensifying.

The tropical depression will move south of a high pressure system over India and the Bay of Bengal. The high will steer the depression toward the west during the next several days. On its anticipated track the tropical depression will approach Sri Lanka in about 36 hours. It will drop heavy rain over parts of Sri Lanka and flash floods could occur.

Tropical Cyclone Nivar Moves along Andhra Pradesh Coast

Tropical Cyclone Nivar moved northward along the coast of Andhra Pradesh on Thursday. At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Nivar was located at latitude 14.0°N and longitude 80.7°E which put it about 50 miles (80 km) south-southeast of Nellore, India. Nivar was moving toward the north 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 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.

After making landfall on the southeast coast of India near Puducherry on Wednesday, vertical wind shear blew the upper portion of Tropical Cyclone Nivar west of the surface circulation. An upper level ridge over India produced easterly winds which blew toward the top of Tropical Cyclone Nivar. Those winds caused strong vertical wind shear. The shear was strong enough to blow the upper part of Nivar west of the surface circulation. The upper part of the circulation moved westward across southern India and weakened. The surface circulation moved northward along the southeast coast of India and back over the Bay of Bengal north of Chennai.

Tropical Cyclone Nivar will move through an environment that will be only slightly favorable for intensification during the next few hours. Nivar will move over water where the Sea Surface Temperature is near 29°C, while it is over the Bay of Bengal. However, the upper level ridge will continue to cause strong vertical wind shear. The shear is likely to prevent Tropical Cyclone Nivar from strengthening.

Tropical Cyclone Nivar will continue to move north along the southeast coast of India for the next few hours. After that time a high pressure system over northern India will turn Nivar toward the west. On its anticipated track Tropical Cyclone Nivar is forecast to move inland over southern Andhra Pradesh and to move toward Karnataka. Nivar will weaken after the low level circulation moves inland, but it will drop locally heavy rain over southern Andhra Pradesh and Karnataka. Flash floods could occur in some locations.

Tropical Cyclone Nivar Makes Landfall in Tamil Nadu

Tropical Cyclone Nivar made landfall on the coast of Tamil Nadu on Wednesday. At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Nivar was located at latitude 12.2°N and longitude 79.8°E which put it about 25 miles (40 km) north of Puducherry, India. Nivar was moving toward the west-northwest at 12 m.p.h. (19 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 976 mb.

Tropical Cyclone Nivar made landfall on the southeast coast of India north of Puducherry on Wednesday. Nivar strengthened into the equivalent of a hurricane/typhoon over the Bay of Bengal before it made landfall. Winds to hurricane/typhoon force extended out 35 miles (55 km/h) from the center of Tropical Cyclone Nivar. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.

Tropical Cyclone Nivar will produce gusty winds along the coast of Tamil Nadu between Cuddalore and Chennai. Winds blowing water toward the coast could cause a storm surge of up to six feet (two meters) between Puducherry and Chennai. Nivar will drop heavy rain over parts of northern Tamil Nadu and flash floods could occur in some locations.

Tropical Cyclone Nivar will move south of a high pressure system over India and the Bay of Bengal. The high will steer Nivar toward the west-northwest. The wind speed will steadily decrease when Tropical Cyclone Nivar moves inland. Nivar will drop locally heavy rain over parts of southern Andhra Pradesh and Karnataka when it moves farther inland over southern India.

Tropical Cyclone Nivar Strengthens near Southeast India

Tropical Cyclone Nivar (04B) strengthened over the Bay of Bengal near Southeast India on Tuesday. At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Nivar was located at latitude 10.8°N and longitude 82.6°E which put it about 235 miles (380 km) southeast of Chennai India. Nivar was moving toward the northwest at 5 m.p.h. (8 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 982 mb.

Tropical Cyclone Nivar strengthened to almost the equivalent of a hurricane/typhoon over the Bay of Bengal near Tamil Nadu on Tuesday. More thunderstorms developed near the center of Nivar. Other strong thunderstorms were occurring in bands north and west of the center of circulation. Bands south and east of the center consisted primarily of showers and lower clouds. Storms near the center generated upper level divergence which pumped mass away to the north and west of the tropical cyclone. Winds to tropical storm force extended out 110 miles (175 km) from the center of circulation.

Tropical Cyclone Nivar will move through an environment favorable for intensification during the next 24 hours. Nivar will move over water where the Sea Surface Temperature is near 29°C. It will move under the western end of an upper level ridge over the Bay of Bengal. The ridge will enhance the upper level divergence and contribute to the removal of mass, which will cause the surface pressure to decrease. Tropical Cyclone Nivar will intensify into the equivalent of a hurricane/typhoon during the next 24 hours.

Tropical Cyclone Nivar will move around the western part of a high pressure system over Bay of Bengal. The high will steer Nivar toward the northwest during the next 24 hours. On its anticipated track Tropical Cyclone Nivar will make landfall on the coast of India between Puducherry and Chennai in about 24 hours. Nivar will bring strong winds to southern India. Wind blowing water toward the coast will cause a storm surge of up to 6 feet (2 meters). Tropical Cyclone Nivar will drop heavy rain over parts of Tamil Nadu and flash floods could occur.

Tropical Cyclone 04B Forms over Bay of Bengal

Tropical Cyclone 04B formed over the Bay of Bengal east of Sri Lanka. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Gati (03A) was located at latitude 9.9°N and longitude 83.0°E which put it about 210 miles (340 km) east-southeast of Puducherry India and about 200 miles (320 km) east of Jaffna, Sri Lanka. It was moving toward the west 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 997 mb.

The circulation around a low pressure system east of Sri Lanka strengthened on Monday. More thunderstorms developed near the center of the low and the wind speeds increased. The distribution of thunderstorms around the low was asymmetrical. Most of the thunderstorms were occurring in bands in the western half of the circulation. Bands in the eastern half of the tropical cyclone consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence which pumped mass away to the west of the tropical cyclone.

Tropical Cyclone 04B will move through an environment that is mostly favorable for intensification during the next during the next 36 hours. It will move over water where the Sea Surface Temperature is near 29°C. The tropical cyclone will move under the southern side of an upper level ridge over the Bay of Bengal. The ridge will produce easterly winds which will blow toward the top of the circulation. Those winds will cause moderate vertical wind shear and they are probably the reason for the asymmetrical distribution of thunderstorms. The wind shear will slow the rate of intensification, but the shear will not be large enough to keep the tropical cyclone from strengthening. Tropical Cyclone 04B could intensify into the equivalent of a hurricane/typhoon with 36 hours.

Tropical Cyclone 04B will move south of a ridge of high pressure over the Bay of Bengal. The high will steer the tropical cyclone toward the west-northwest. On its anticipated track the center of Tropical Cyclone 04B will pass north of Sri Lanka in about 24 hours. The tropical cyclone will approach the coast of India near Puducherry in 36 hours. It could be the equivalent of a hurricane/typhoon when it reaches the southeast coast of India.

Tropical Cyclone 04B will drop locally heavy rain over northern Sri Lanka. It will bring strong winds and locally heavy rain to southern India later this week. Heavy rain could cause flash floods in some locations.

Elsewhere, Tropical Cyclone Gati weakened as it moved across northeastern Somalia toward the Gulf of Aden. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Gati (03A) was located at latitude 11.9°N and longitude 47.5°E which put it about 45 miles (75 km) northwest of Maydh, Somalia. Gati was moving toward the west-northwest at 13 m.p.h. (20 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 1003 mb.

Tropical Cyclone Gati Intensifies Explosively near Somalia

Tropical Cyclone Gati intensified explosively near the northeast coast of Somalia during Saturday night. At 4:00 a.m. EST on Sunday the center of Tropical Cyclone Gati (03A) was located at latitude 10.3°N and longitude 52.0°E which put it about 70 miles (110 km) east of Hafun, Somalia. It was moving toward the west at 16 m.p.h. (26 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 954 mb.

Tropical Cyclone Gati strengthened extremely rapidly on Saturday night. A circular eye with a diameter of 17 miles (28 km) developed at the center of Gati. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Storms around the core of Gati generated very strong upper level divergence which pumped mass away from the tropical cyclone. The removal of large amounts of mass allowed the surface pressure to decrease very rapidly, which contributed to the explosive intensification.

The circulation around Tropical Cyclone Gati was very small. Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Gati. Winds to tropical storm force extended out 60 miles (95 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Gati was 20.6. The Hurricane Size Index (HSI) was 5.5 and the Hurricane Wind Intensity Size Index (HWISI) was 26.1. The structure of Gati was similar to that of midget typhoons sometimes observed over the Western North Pacific Ocean.

Tropical Cyclone Gati could strengthen further during the next few hours before it makes landfall on the northeast coast of Somalia. Gati will move over water where the Sea Surface Temperature is near 27°C. It will move through an area where the upper level winds are weak and there will be little vertical wind shear. Tropical Cyclone Gati will weaken quickly after it makes landfall in Somalia.

Tropical Cyclone Gati will move south of a high pressure system over th Arabian Peninsula. The high will steer Gati toward the west during the next 36 to 48 hours. On its anticipated track Tropical Cyclone Gati wil make landfall near Hafun, Somalia in about six hours. Gati will be capable of causing major damage around Hafun. It will drop heavy rain over parts of northeastern Somalia and flash floods could occur.

Tropical Cyclone 03A Forms East of Somalia

Tropical Cyclone 03A formed over the Arabian Sea east of Somalia on Saturday. At 4:00 p.m. EST on Saturday the center of Tropical Cyclone 03A was located at latitude 10.8°N and longitude 55.0°E which put it about 270 miles (435 km) east of Hafun, Somalia. It was moving toward the west at 17 m.p.h. (26 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 1000 mb.

More thunderstorms developed near the center of a low pressure system east of Somalia on Saturday and it strengthened into Tropical Cyclone 03A. Bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence which pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 75 miles (120 km) from the center of the tropical cyclone.

Tropical Cyclone 03A will move through an environment somewhat favorable for intensification during the next 24 hours. It will move over water where the Sea Surface Temperature is near 27°C. The tropical cyclone will move under the southern portion of an upper level ridge over southern Asia. The ridge will produce easterly winds which will blow toward the top of the tropical cyclone. Those winds will cause moderate vertical wind shear. The shear will inhibit intensification, but Tropical Cyclone 03A is likely to strengthen during the next 24 hours in spite of the wind shear.

Tropical Cyclone 03A will move south of a high pressure system over the Arabian Peninsula. The high will steer the tropical cyclone toward the west during the next 24 hours. On its anticipated track Tropical Cyclone 03A will pass south of Socotra Island during the next 12 hours. It will approach the coast of Somalia near Hafun in about 24 hours. The tropical cyclone will bring gusty winds and locally heavy rain to northeastern Somalia in about a day or so.

Tropical Cyclone Alicia Develops East of Diego Garcia

Tropical Cyclone Alicia developed east of Diego Garcia on Friday. At 10:00 p.m. EST on Friday the center of Tropical Cyclone Alicia was located at latitude 7.8°N and longitude 79.1°E which put it about 495 miles (795 km) east of Diego Garcia. Alicia was moving toward the west-southwest at 23 m.p.h. (37 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 991 mb.

The circulation around a low pressure system east of Diego Garcia exhibited more organization on Friday and the system was designated as Tropical Cyclone Alicia. The inner end of a rainband wrapped around the western and northern sides of the center of circulation. Other bands of showers and thunderstorms were revolving around the center of Alicia. Storms near the center generated upper level divergence which pumped mass away from the tropical storm. Winds to tropical storm force extended out 130 miles (210 km) from the center of circulation.

Tropical Cyclone Alicia will move through an environment that will be favorable for intensification during the next 36 hours. Alicia will move over water where the Sea Surface Temperature is near 29°C. Alicia will be under an upper level ridge where the winds are weaker and there will be little vertical wind shear. Tropical Cyclone Alicia could strengthen into the equivalent of a hurricane/typhoon within 36 hours.

Tropical Cyclone Alicia will move around the western end of a high pressure system over the southeastern Indian Ocean. The high will steer Alicia toward the south-southwest during the next several days. On its anticipated track Tropical Cyclone Alicia will pass southeast of Diego Garcia and east of Rodrigues.

Tropical Cyclone Nisagra Makes Landfall South of Mumbai

Tropical Cyclone Nisarga made landfall south of Mumbai, India on Wednesday.  At 5:00 a.m. EDT on Wednesday the center of Tropical Cyclone Nisarga was located at latitude 18.3°N and longitude 73.3°E which put it about 80 miles (130 km) south of Mumbai, India.  Nisarga was moving toward the northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 973 mb.

Tropical Cyclone Nisarga rapidly intensified into the equivalent of a hurricane/typhoon on Tuesday night before it made landfall on the west coast of India.  An eye with a diameter of 40 miles (65 km) formed at the center of Nisarga.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Tropical Cyclone Nisarga at the time of landfall.  Winds to tropical storm force extended out 100 miles (160 km) from the center.

Tropical Cyclone Nisarga brought winds to hurricane/typhoon force to a portion of the west coast of India south of Mumbai.  Those winds would have pushed water toward the coast.  The would have generated a storms surge of 3 to 6 feet (1 to 2 meters) near where the center of Nisarga made landfall.  Tropical Cyclone Nisarga will drop heavy rain over parts of Maharashtra.  Heavy rain could cause flash floods in some locations.

Strengthening Tropical Cyclone Nisarga Nears Mumbai

Strengthening Tropical Cyclone Nisarga neared  Mumbai, India on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Cyclone Nisarga was located at latitude 17.6°N and longitude 72.4°E which put it about 140 miles (225 km) south-southwest of Mumbai, India.  Nisarga was moving toward the northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 985 mb.

Tropical Cyclone Nisarga strengthened quickly on Tuesday night as it moved closer to the west coast of India.  An eye with a diameter of 40 miles (65 km) formed at the center of circulation.  A ring of 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 Nisarga.  Storms near the core were generating upper level divergence which was pumping mass away to the east of the tropical cyclone.  Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Cyclone Nisarga will move around the western end of a high pressure system over India.  The high will steer Nisarga toward the northeast during the next 24 hours.  On its anticipated track the center of Tropical Cyclone Nisarga will make landfall on the west coast of India south of Mumbai in a few hours.

Tropical Cyclone Nisarga will continue to intensify until it makes landfall.  Nisarga will move over water where the Sea Surface Temperature is near 31°C.  It will move under the western part of an upper level ridge centered over India.  The ridge will produce southerly winds which will blow toward the top of Nisarga.  Those winds will cause some vertical wind shear, but the shear will not be great enough to prevent intensification.  Tropical Cyclone Nisarga is likely to strengthen into the equivalent of a hurricane/typhoon before it makes landfall.

Tropical Cyclone Nisarga will bring strong winds to the west coast of India.  Those winds will push water toward the coast and they could cause a storm surge of 3 to 6 feet (1 to 2 meters) near Mumbai and near where the center makes landfall.  Nisarga will also drop heavy rain over parts of Maharashtra.  Locally heavy rain could cause flash floods in some locations.