Category Archives: Indian Ocean

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.

Tropical Cyclone Amphan Makes Landfall Near Kolkata

The center of Tropical Cyclone Amphan made landfall on the north coast of the Bay of Bengal near Kolkata, India on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Cyclone Amphan was located at latitude 22.7°N and longitude 88.4°E which put it about 30 miles (50 km) south-southwest of Kolkata, India.  Amphan was moving toward the north-northeast at 19 m.p.h. (30 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 979 mb.

The center of Tropical Cyclone Amphan made landfall near Haldia, India which is a little to the south-southwest of Kolkata on Wednesday.  The maximum sustained wind speed in Amphan at the time of landfall was 100 m.p.h. (160 km/h).  Tropical Cyclone Amphan weakened after the center moved over land.  Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km) to the southeast of the center.  The stronger winds were occurring near the center of circulation and over the northern Bay of Bengal.

When Tropical Cyclone Amphan approached the coast, the heaviest rain occurred in bands in the western side of Amphan.  Heavy rain fell over parts of northern Odisha and West Bengal.  After the center of Amphan made landfall and the tropical cyclone moved inland, the heaviest rain fell in bands in the northeastern part of the circulation.  Heavy rain was falling over parts of Bangladesh.

Strong southerly winds blowing toward the north coast of the Bay of Bengal pushed water toward Bangladesh and the coast of India south of Kolkata.  The coast around the northern Bay of Bengal is very vulnerable to storm surges caused by tropical cyclones.  Tropical Cyclone Amphan likely caused a significant storm surge along that coast.

Tropical Cyclone Amphan will move around the northwestern part of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north-northeast.  On its anticipated track the center of Tropical Cyclone Amphan will move across western Bangladesh and northeastern India.  The circulation around Amphan will continue to weaken as the system moves farther inland.  Tropical Cyclone Amphan will continue to drop locally heavy rain over Bangladesh and northeastern India.  Heavy rain could cause flash floods to occur in some locations.

Large Dangerous Tropical Cyclone Amphan Nears Kolkata and Bangladesh

Large dangerous Tropical Cyclone Amphan neared Kolkata, India and Bangladesh late on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Amphan was located at latitude 18.8°N and longitude 87.0°E which put it about 310 miles (505 km) south-southwest of Kolkata, India.  Amphan was moving toward the north at 10 m.p.h. (16 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. (230 km/h).  The minimum surface pressure was 951 mb.

Tropical Cyclone Amphan was the equivalent of a major hurricane as it neared Kolkata, India and the coast of Bangladesh on Tuesday.  An eyewall replacement cycle caused the circulation around Amphan to expand in size.  Some satellite images showed evidence of the remnants of the original small inner eye inside the larger second eye.  The larger eye was surrounded by a ring of strong 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 Amphan.

Tropical Cyclone Aphan had a large circulation that covered much of the northern Bay of Bengal.  Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Amphan was 20.6.  The Hurricane Size Index (HSI) was 20.8 and the Hurricane Wind Intensity Size Index (HWISI) was 41.4.  Amphan was capable of causing major damage.

Tropical Cyclone Amphan will move through an environment capable of supporting a large powerful tropical cyclone during the next 12 to 18 hours.  Amphan will move over water where the Sea Surface Temperature is near 30°C.  It will move under the western side of an upper level ridge.  The upper level winds will be weak and there will be little vertical wind shear.  The circulation around Tropical Cyclone Amphan could start to pull in some drier air that is over eastern India when it get closer to the coast.  Amphan will remain a large dangerous tropical cyclone until it makes landfall on the north coast of the Bay of Bengal.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north-northeast during the next 36 hours.  On its anticipated track the center of Tropical Cyclone Amphan will pass near Puri, India in about 12 hours.  The center of Amphan could make landfall south of Kolkata near Haldia, India in about 18 hours.  Tropical Cyclone Amphan could cause major damage.  The wind will blow water toward the coast around the northern Bay of Bengal.  Amphan could generate a storms surge of up to 12 to 15 feet (3 to 4 meters) along past of the Bangladesh coast.  Tropical Cyclone Amphan will also drop heavy rain over parts of northeastern India and Bangladesh when it moves inland.  The heavy rain is likely to cause floods in some locations.

 

Tropical Cyclone Amphan Intensifies Into Equivalent of Cat. 5 Hurricane

Tropical Cyclone Amphan intensified into equivalent of a Category 5 hurricane on the Saffir-Simpson Scale over the Bay of Bengal on Monday.  At 5:00 a.m. EDT on Monday the center of Tropical Cyclone Amphan was located at latitude 13.9°N and longitude 86.5°E which put it about 635 miles (1025 km) south-southwest of Kolkata, India.  Amphan was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 909 mb.

The circulation around Tropical Cyclone Amphan appeared to develop a concentric eyewall structure on Monday.  The inner end of a rainband wrapped around the original small eye and eyewall.  The inner eye had a diameter of 10 miles (16 km).  A ring of strong thunderstorms surrounded the inner eye and the strongest winds were occurring in that ring of storms.  An outer eyewall with a diameter of 50 mile (80 km) surrounded the inner eye.    Bands of showers and thunderstorms were revolving around the concentric eyewalls.  Storms in the core of Amphan were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.

Tropical Cyclone Amphan had a large circulation.  Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (325 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Amphan was 35.0.  The Hurricane Size Index (HSI) was 16.5 and the Hurricane Wind Intensity Size Index (HWISI0 was 51.5.  Tropical Cyclone Amphan was capable of causing catastrophic damage.

Tropical Cyclone Amphan will move through an environment very favorable for a strong tropical cyclone during the next 36 hours.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under an upper level ridge where the upper level winds are weak.  There will be little vertical wind shear.  The eyewall replacement cycle will stop the intensification of Tropical Cyclone Amphan.  Amphan will weaken, at least temporarily, when the inner eyewall dissipates.  When that occurs the strongest winds will be occurring in the outer eyewall.  The eyewall replacement cycle could cause the circulation to increase in size.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north-northeast.  On its anticipate track the center of Tropical Cyclone Amphan will approach the coast around the northern Bay of Bengal in 36 hours.  Amphan will be a large dangerous tropical cyclone when it approaches the coast.  Tropical Cyclone Amphan will generate a significant storm surge along the coast of Bangladesh.  Amphan will cause major wind damage.  It will drop locally heavy rain over northeast India and Bangladesh.  Freshwater flooding will occur.

Tropical Cyclone Amphan Rapidly Intensifies Into Equivalent of Major Hurricane

Tropical Cyclone Amphan rapidly intensified into the equivalent of a major hurricane over the Bay of Bengal on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Amphan was located at latitude 13.3°N and longitude 86.4°E which put it about 675 miles (1090 km) south-southwest of Kolkata, India.  Amphan was moving toward the north at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 919 mb.

Tropical Cyclone Amphan rapidly intensified into a large powerful tropical cyclone on Sunday night.  A small circular eye was at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Amphan.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.

The circulation around Tropical Cyclone Amphan grew in size on Sunday.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 210 miles (335 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Amphan was 31.6.  The Hurricane Size Index was 16.8 and the Hurricane Wind Intensity Size Index (HWISI) was 48.4.  Tropical Cyclone Amphan was capable of causing widespread significant damage.

Tropical Cyclone Amphan will remain in an environment capable of supporting a strong tropical cyclone during the next 36 to 48 hours.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under an upper level ridge.  The upper level wind will be weak and there will be little vertical wind shear.  The ridge will actually enhance the upper level divergence.  If a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Tropical Cyclone Amphan to weaken.  Tropical Cyclone Amphan is likely to remain a large, powerful tropical cyclone during the next 48 hours.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north.  On its anticipated track Tropical Cyclone Amphan could approach the coast of Bangladesh in 48 hours.  Amphan is could still be the equivalent of a major hurricane when it reaches Bangladesh.  Tropical Cyclone Amphan could generate a significant storm surge at the coast.  Amphan will cause major wind damage and heavy rain could cause freshwater flooding.

Tropical Cyclone Amphan Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Amphan strengthened to the equivalent of a hurricane/typhoon on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Cyclone Amphan was located at latitude 12.3°N and longitude 86.4°E which put it about 695 miles (1120 km) south-southwest of Kolkata, India.  Amphan was moving toward the north at 7 m.p.h. (11 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 969 mb.

Tropical Cyclone Amphan continued to intensify on Sunday.  A small circular eye with a diameter of 10 miles (16 km) developed at the center of circulation.  A ring of strong thunderstorms surround the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Amphan.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.  Wins to hurricane/typhoon force extended out 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center.

Tropical Cyclone Amphan will move through an environment favorable for intensification during the next 36 to 48 hours.  Amphan will move over water where Sea Surface Temperature is near 31°C.  It will move under an upper level ridge over the Bay of Bengal.  The winds in the upper level ridge are weak and there will be little vertical wind shear.  Tropical Cyclone Amphan will continue to intensify and it is likely to strengthen into the equivalent of a major hurricane.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north during the next 48 hours.  On its anticipated track Tropical Cyclone Amphan will approach the coast around the northern Bay of Bengal in less than 72 hours.  Amphan will bring strong winds and locally heavy rain to northeast India and to Bangladesh.  Tropical Cyclone Amphan is likely to generate a significant storm surge along the northern coast of the Bay of Bengal.

Tropical Cyclone Amphan Develops Quickly Over Bay of Bengal

Tropical Cyclone Amphan developed quickly over the Bay of Bengal on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Amphan was located at latitude 11.2°N and longitude 86.3°E which put it about 430 miles (695 km) west of Port Blair.  Amphan was moving toward the north at 8 m.p.h (13 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 992 mb.

The circulation around a low pressure system over the Bay of Bengal organized quickly on Saturday and the Indian Meteorological Department designated the system as Tropical Cyclone Amphan.  Thunderstorms formed around the center of Amphan and recent microwave images suggested that an eye could be forming.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Amphan.  The stronger bands were in the western half of the circulation.  Storms near the core of the circulation were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Amphan.

Tropical Cyclone Amphan will move through an environment very favorable for intensification.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under the axis of an upper level ridge over the Bay of Bengal.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Amphan is likely to intensify rapidly during the next 36 hours.  Amphan is likely to strengthen into the equivalent of a hurricane/typhoon within 24 hours and it could become the equivalent of a major hurricane within 36 to 48 hours.

Tropical Cyclone Amphan will move around the eastern end of a high pressure system over southeast Asia.  The high will steer Amphan toward the north during the next several days.  On its anticipated track Tropical Cyclone Amphan could approach the coast of northeast Indian and Bangladesh in 72 hours.  Amphan will likely be the equivalent of a major hurricane when it approaches the coast.  Tropical Cyclone Amphan could generate a catastrophic storm surge along the north coast of the Bay of Bengal.

Tropical Cyclone Jeruto Develops Southeast of Diego Garcia

Tropical Cyclone Jeruto developed over the South Indian Ocean southeast of Diego Garcia on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Jeruto was located at latitude 16.4°S and longitude 82.7°E which put it about 950 miles (1535 km) southeast of Diego Garcia.  Jeruto was moving toward the west-southwest 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 1003 mb.

The distribution of thunderstorms around Tropical Cyclone Jeruto was asymmetrical.  The strongest thunderstorms were occurring in bands southeast of the center of circulation.  An upper level trough east of Madagascar and an upper level ridge over the South Indian Ocean were interacting to produce strong northwesterly winds.  Those winds were blowing across the top of Tropical Cyclone Jeruto and they were causing strong vertical wind shear.  The strong shear was blowing the upper portion of the tropical cyclone to the southeast of the lower level circulation.  The strong wind shear was the reason for the asymmetrical distribution of thunderstorms.  Bands closer to the center of circulation consisted primarily of showers and lower clouds.

Tropical Cyclone Jeruto will move through an environment unfavorable for intensification during the next several days.  Jeruto will move over water where the Sea Surface Temperature is near 27°C.  So, there will be enough energy in the upper ocean to support intensification.   However, the upper level trough and ridge will continue to cause strong vertical wind shear.  The shear could be strong enough to blow the upper part of Tropical Cyclone Jeruto to the southeast of the lower level circulation.  Jeruto is likely to weaken during the next several days.

Since Tropical Cyclone Jeruto is likely to weaken and the circulation become more shallow, it will be steered by winds in the lower troposphere.  Those winds will steer Jeruto toward the west-southwest during the next several days.  On its anticipated track Tropical Cyclone Jeruto will pass well south of Diego Garcia.

Major Tropical Cyclone Harold Nears Vanuatu

Major Tropical Cyclone Harold neared Vanuatu on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Vanuatu was located at latitude 15.5°S and longitude 166.0°E which put it about 80 miles (130 km) west-northwest of Unmet, Vanuatu.  Harold was moving toward the southeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 949 mb.

Tropical Cyclone Harold intensified into the equivalent of a major hurricane.  The original small eye dissipated but a new larger eye developed on Saturday night.  The new eye was surround by a ring of strong 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 Harold.  The strongest rainbands were in the eastern and southern parts of the circulation.  Storms near the core of Harold generated upper level divergence which pumped mass away from the center of the tropical cyclone.

Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 125 miles (200 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Harold was 22.1.  The Hurricane Size Index (HSI) was 11.1 and the Hurricane Wind Intensity Size Index (HWISI) was 33.2.  Tropical Cyclone Harold was capable of causing major damage.

Tropical Cyclone Harold will move through an environment favorable for intensification during the next 24 hours.  Harold will move over water where the Sea Surface Temperature is near 30°C.  It will move around the southwestern part of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear and the wind shear could be strong enough to limit intensification.  Tropical Cyclone Harold could intensify further, but it may maintain its intensity on Sunday.

The ridge over the South Pacific Ocean will steer Tropical Cyclone Harold slowly toward the southeast during the next 24 hours.  On its anticipated track the core of Harold with the strongest winds will move slowly toward Malekula.  Tropical Cyclone Harold will drop heavy rain over central Vanuatu.  The slow movement of Harold could create the potential for very serious flooding on Espiritu Santo, Malekula, Ambrym and Epi.

Elsewhere in the tropics, Tropical Cyclone Irondro began to slowly weaken over the South Indian Ocean.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Irondro was located at latitude 23.3°S and longitude 81.5°E which put it about 1275 miles (2060 km) southwest of Cocos Island.  Irondro was moving toward the southeast at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 958 mb.