Category Archives: Indian Ocean

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.

Tropical Cyclone Harold Rapidly Intensifies into Equivalent of Hurricane/Typhoon

Tropical Cyclone Harold rapidly intensified into the equivalent of a hurricane/typhoon west-northwest of Vanuatu on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Harold was located at latitude 14.1°S and longitude 164.1°E which put it about 170 miles (275 km) west-northwest of Nokuku, Vanuatu.  Harold was moving toward the southeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 959 mb.

The circulation around Tropical Cyclone Harold organized quickly on Friday.  The inner end of a rainband wrapped around the center of circulation and a small eye formed.  A 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 Harold.  The strongest rainbands were in the eastern half of the circulation.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Storms around the core of the circulation generated strong upper level divergence which pumped mass away to the east of the tropical cyclone.

Winds to hurricane/typhoon force extend out 35 miles (55 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Tropical Cyclone Harold was 17.8.  The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 29.8.  Harold was capable of causing serious damage.

Tropical Cyclone Harold will move through an environment favorable for intensification during the next 24 to 48 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, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Harold will strengthen into the equivalent of a major hurricane during the next 12 hours.

The upper level ridge will steer Tropical Cyclone Harold slowly toward the southeast during the weekend.  On its anticipated track Harold will gradually approach Espiritu Santo and Malekula in Vanuatu.  The core of Tropical Cyclone Harold could move across the central part of Vanuatu in 48 to 72 hours.  Harold is likely to be the equivalent of a major hurricane at that time.

Elsewhere in the tropics, Tropical Cyclone Irondro intensified into the equivalent of a hurricane/typhoon over the South Indian Ocean.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Irondro was located at latitude 19.9°S and longitude 76.4°E which put it about 885 miles (1425 km) south-southeast of Diego Garcia.  Irondro was moving toward the east-southeast at 21 m.p.h. (33 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. (170 km/h).  The minimum surface pressure was 973 mb.

Tropical Cyclone Irondro Forms South-southwest of Diego Garcia

Tropical Cyclone Irondro formed south-southwest of Diego Garcia on Thursday.  At 5:00 a.m. EDT on Thursday the center of Tropical Cyclone Irondro was located at latitude 13.5°S and longitude 69.9°E which put it about 460 miles (745 km) south-southwest of Diego Garcia.  Irondro was moving toward the southeast at 5 m.p.h. (8 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.

A distinct low level center of circulation developed in an area of thunderstorms over the South Indian Ocean south-southwest of Diego Garcia on Thursday and the system was designated as Tropical Cyclone Irondro.  The circulation around Irondro was still organizing.  Bands of showers and thunderstorms were forming and the bands were beginning to revolve around the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out 145 miles (230 km) from the center of circulation.

Tropical Cyclone Irondro will move through an environment favorable for intensification during the next 48 to 60 hours.  Irondro will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level high over the South Indian Ocean.  The high will produce northwesterly winds which will blow toward the top of the tropical cyclone.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Irondro will intensify and it could strengthen into the equivalent of a hurricane/typhoon.

The upper level high and an upper level trough east of Madagascar will interact to steer Tropical Cyclone Irondro toward the southeast during the next few days.  On its anticipated track Irondro will pass south of Diego Garcia and south of Cocos Island.

Tropical Cyclone Herold Brings Wind, Rain to Rodrigues

Tropical Cyclone Herold brought wind and rain to Rodrigues on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Herold was located at latitude 21.4°S and longitude 64.1°E which put it about 125 miles (200 km) south-southeast of Port Mathurin, Mauritius.  Herold was moving toward the southeast at 21 m.p.h. (34 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 978 mb.

The core of Tropical Cyclone Herold passed west of Rodrigues on Tuesday, but it came close enough to that island to bring gusty winds and locally heavy rain.  A weather station at the Plaine Corail airport on Rodrigues reported a wind gust of 80 m.p.h. (130 km/h).

Although Tropical Cyclone Herold began to weaken on Tuesday.  It remained strong enough to generate wind gusts to hurricane/typhoon force over parts of Rodrigues.  Microwave satellite imagery indicated the there was still an eye at the center of Herold, although the eye was not evident on conventional infrared images.  The eye was surround by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 150 miles (240 km) from the center.

Tropical Cyclone Herold will continue to weaken during the next several days.  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 Herold.  Those winds will cause strong vertical wind shear and they will cause the tropical cyclone to weaken.

The upper level trough and ridge will steer Tropical Cyclone Herold toward the southeast.  On its anticipated track Herold will move quickly away from Rodrigues.  Weather conditions on that island will gradually improve as Tropical Cyclone Herold moves farther away.