Category Archives: Indian Ocean

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.

Tropical Cyclone Nisarga Develops West of India

Tropical Cyclone Nisarga developed west of India on Tuesday.  At 5:00 a.m. EDT on Tuesday the center of Tropical Cyclone Nisarga was located at latitude 16.0° and longitude 71.2°E which put it about 225 miles (365 km) south-southwest of Mumbai, India.  Nisarga was moving toward the north at 8 m.p.h. (13 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.

The circulation around a low pressure system over the Arabian Sea west of India strengthened on Tuesday and the India Meteorological Department designated the system as Tropical Cyclone Nisarga.  More thunderstorms developed near the center of Nisarga.  Numerous bands of showers and thunderstorms were revolving around the center of circulation.  The strongest rainbands were in the western half of the tropical cyclone.  Storms near the center of circulation generated upper level divergence which pumped mass away from the tropical cyclone.

Tropical Cyclone Nisarga will move through an environment favorable for intensification during the next 24 hours.  Nisarga will move over water where the Sea Surface Temperature is near 31°C.  It will move under the western side of an upper level ridge centered over India.  The ridge will produce southerly winds which will blow toward the top of the circulation.  Those winds will produce some vertical wind shear, but the shear will not be strong enough to prevent the intensification of Tropical Cyclone Nisagra.  Nisagra could strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Nisarga will move around the western end of a high pressure system over India.  The high will steer Nisarga toward the north during the next 12 hours.  Nisarga will move more toward the north-northeast when it moves around the northwestern part of the high pressure system.  On its anticipated track Tropical Cyclone Nisarga could approach Mumbai in about 24 hours.  Nisarga could be the equivalent of a hurricane/typhoon when it approaches Mumbai.

Tropical Cyclone Nisarga will bring gusty winds and locally heavy rain to Mumbai on Wednesday.  Nisarga could also cause a storm surge of  3 to 6 feet (1 to 2 meters) in the area around Mumbai where the wind blows the water toward the coast.  Tropical Cyclone Nisarga will drop locally heavy rain over parts of Maharashtra and southern Gujarat.  Heavy rain could cause flash floods in some locations,

Tropical Depression Forms Near Western Oman

A Tropical Depression formed over the Arabian Sea near the coast of western Oman on Friday.  At 2:00 p.m. EDT on Friday the center of the tropical depression was located at latitude 16.8°N and longitude 54.2°E which put it about 10 miles (15 km) southeast of Salalah, Oman.  The depression was moving toward the west-northwest at 2 m.p.h. (3 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 1004 mb.

More thunderstorms developed near the center of a small low pressure system near the coast of western Oman on Friday and the India Meteorological Department classified the system as a depression.  Thunderstorms were forming near the center of the depression.  Bands of showers and thunderstorms were revolving around the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away from the depression in all directions.

The tropical depression will move through an environment favorable for intensification if the center remains over water.  It will move over water where the Sea Surface Temperature is near 31°C.  The depression will be under an upper level ridge where the winds are weak.  There will be little vertical wind shear and the upper level ridge will enhance upper level divergence.  If the center of the tropical depression remains over the Arabian Sea, then it is likely to strengthen into the equivalent of a tropical storm during the next 24 to 48 hours.  If the center of circulation moves inland over western Oman and eastern Yemen, then intensification becomes much less likely.

The tropical depression will move under the upper level ridge and the steering winds will be very weak.  The depression is forecast to drift very slowly toward the west during the next several days,  The center of the depression could remain just off the coast or it could move slowly inland.  The slow movement of the depression will allow it to drop locally heavy rain over parts of western Oman and eastern Yemen.  The heavy rain could very likely cause flash floods in some locations.

Tropical Cyclone Mangga Brings Wind and Rain to Cocos Island

Tropical Cyclone Mangga brought wind and rain to Cocos Island on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Mangga was located at latitude 16.3°S and longitude 97.6°E which put it about 270 miles (435 km) south of Cocos Island.  Mangga was moving toward the southeast at 21 m.p.h. (34 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.

The center of Tropical Cyclone Mangga passed southwest of Cocos Island on Friday.  The circulation around Mangga was fairly large.  Winds to tropical storm force extended out 150 miles (240 km) to the northeast of the center of circulation.  A weather station on Cocos Island reported a sustained wind speed of 27 m.p.h. (43 km/h) and a wind gust of 38 m.p.h. (61 km/h).  The station measured 1.25 inches (32 mm) of rain during the passage of Tropical Cyclone Mangga.

The circulation around Tropical Cyclone Mangga did not appear to be well organized.  There were not a lot of thunderstorms near the center or circulation.  Bands near the center consisted primarily of showers and lower clouds.  Thunderstorms were occurring to the southeast of the low level center of circulation.  The thunderstorms appeared to be associated with a circulation in the middle and upper troposphere.  Those thunderstorms were generating upper level divergence which was pumping mass away to the southeast of Tropical Cyclone Mangga.

Tropical Cyclone Mangga will move through an environment only marginally favorable for intensification.  Mangga will move over water where the Sea Surface Temperature is near 27°C.  However, an upper level ridge northwest of Australia and an upper level trough west of Australia will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause strong vertical wind shear.  The shear is likely to be strong enough to prevent intensification of the current low level center of Tropical Cyclone Mangga.  It is possible that the circulation in the middle and upper troposphere could cause a new low level center to form.  If a new center forms where the thunderstorms and upper level divergence are occurring, then some intensification might be possible.

Tropical Cyclone Mangga will move around the southwestern part of a high pressure system centered over Australia.  The high will steer Mangga quickly toward the southeast.  On its anticipated track the center of Tropical Cyclone Mangga could reach the coast of Western Australia in less than 36 hours.  Mangga could produce winds to tropical storm force along the coast of Western Australia.

Tropical Cyclone Mangga Develops Northwest of Cocos Islands

Tropical Cyclone Mangga developed over the South Indian Ocean northwest of the Cocos Islands on Thursday.  At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Mangaa was located at latitude 9.4°S and longitude 93.1°E which put it about 320 miles (515 km) northwest of Cocos Island.  Mangga was moving toward the south-southeast at 7 m.p.h. (12 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.

The Australian Bureau of Meteorology issued a Warning for the Cocos Islands.

Tropical Cyclone Mangga developed within a trough of low pressure that extended from southwest of Indonesia to western Australia.  The trough had persisted for several days and a center of low pressure gradually formed northwest of the Cocos Islands during the past 24 hours.  The Australian Bureau of Meteorology designated the system as Tropical Cyclone Mangga on Thursday.

The circulation around Tropical Cyclone Mangga was still in the process of organizing.  The strongest thunderstorms were in a band on the western side of the circulation.  Bands on the eastern side of the circulation consisted primarily of showers and lower clouds.  More thunderstorms began to develop near the center of circulation on Thursday.  Storms developing near the center started to generate upper level divergence which was pumping mass away to the west of the tropical cyclone.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Mangga.

Tropical Cyclone Mangga will move through an environment somewhat favorable for intensification during the next 24 to 36 hours.  Mannga will move over water where the Sea Surface temperature is near 27°C.  It will move under the northwestern part of an upper level ridge centered over Indonesia.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will produce moderate vertical wind shear.  The wind shear may be the reason why the bands on the eastern side of Tropical Cyclone Mangga are weaker.  The shear will also inhibit intensification, but it will probably not be strong enough to prevent Manga from strengthening during the next 24 hours.

Tropical Cyclone Mangga will move around the western end of a high pressure system centered north of Australia.  The high will steer Mangga toward the southeast during the next few days.  On its anticipated track Tropical Cyclone Mangga will pass near the Cocos Islands in about 24 hours.  Manga will bring gusty winds and locally heavy rain to those islands.