Category Archives: Indian Ocean

Tropical Cyclone Bulbul Moving Toward Kolkata

Tropical Cyclone Bulbul moved toward Kolkata, India on Friday.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Bulbul was located at latitude 19.7°N and longitude 87.8°E which put it about 225 miles (360 km) south of Kolkata, India.  Bulbul was moving toward the north at 8 m.p.h. (13 k/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 861 mb.

It appeared that Tropical Cyclone Bulbul may have pulled drier air from India around the southern and eastern sides of its circulation.  Rainbands in those parts of the tropical cyclone consisted primarily of showers and lower clouds.  Microwave satellite images provided some evidence of an eye at the center of circulation.  A ring of thunderstorms around the eye exhibited weaker sections on the eastern side of the eye.  The strongest winds were occurring in the ring of storms.  Other strong bands of thunderstorms were present in the western half of the circulation.

Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Tropical Cyclone Bulbul.  Winds to tropical storm force extended out 140 miles (220 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Bulbul was 16.5.  The Hurricane Size index (HSI) was 13.2 and the Hurricane Wind Intensity Size Index (HWISI) was 29.7.  Bulbul was capable of causing serious damage.

Tropical Cyclone Bulbul may be near its maximum intensity.  Bulbul will move over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy in the upper Bay of Bengal to support further intensification.  However, the introduction of drier air into the southern and eastern parts of the circulation will inhibit the development of thunderstorms in those portions of the tropical cyclone.  Bulbul will move under the western end of an upper level ridge over southeast Asia.  The ridge will produce some vertical wind shear which will also inhibit further intensification.  Tropical Cyclone Bulbul could weaken when it nears the coast around the northern Bay of Bengal.

Tropical Cyclone Bulbul will move around the western end of the ridge over southeast Asia.  The ridge will steer Bulbul toward the north for another 18 to 24 hours.  On its anticipated track Tropical Cyclone Bulbul could approach the coast of India south of Kolkata in about 18 hours.  Bulbul will turn more toward the east when it moves around the northwestern part of the ridge in a day or so.

Tropical Cyclone Bulbul could be the equivalent of a hurricane/typhoon when it makes landfall in West Bengal south of Kolkata.  Bulbul will bring gusty winds to the coast of West Bengal and Bangladesh.  Tropical Cyclone Bulbul will be capable of generating a storm surge of up to 6 to 9 feet ( 2 to 3 meters) along portions of the coast around the northern Bay of Bengal.  That area is particularly prone to storm surges.  Bulbul will drop locally heavy rain over parts of West Bengal and Bangladesh when it moves inland.  Locally heavy rain could cause flash floods in some locations.

Tropical Cyclone Bulbul Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Bulbul strengthened into the equivalent of a hurricane/typhoon over the Bay of Bengal on Thursday.  At 4:00 p.m. EST on Thursday the center of Tropical Cyclone Bulbul was located at latitude 16.5°N and longitude 87.5°E which put it about 400 miles (645 km) south of Kolkata, India.  Bulbul was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 976 mb.

The circulation around Tropical Cyclone Bulbul exhibited greater organization on Thursday.  Microwave satellite imagery indicated that an eye was forming at the center of circulation.  A ring of thunderstorms was developing around the eye and the strongest winds were occurring in that ring of storms.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Bulbul.  The strongest rainbands were in the northwestern half of Bulbul.  Winds to hurricane/typhoon force extended out 15 miles (25 km) from the center of circulation.  Winds to tropical storm force extended out 145 miles (230 km) from the center.

Tropical Cyclone Bulbul will move through an environment favorable for intensification during the next 24 to 36 hours.  Bulbul 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 southeast Asia.  The upper level ridge will produce southerly winds which will blow toward the top of the circulation.  There will be southerly winds at all levels and there will not be a lot of vertical wind shear.  Tropical Cyclone Bulbul will intensify during the next 24 to 36 hours.

The ridge over southeast Asia will steer Tropical Cyclone Bulbul toward the north during the next several days.  On its anticipated track Tropical Cyclone Bulbul could approach the area around Kolkata, India in less than 48 hours.  Bulbul could be the equivalent of a hurricane/typhoon when it approaches the coast around the northern end of the Bayof Bengal.

Tropical Cyclone Bulbul Strengthens over Bay of Bengal

Tropical Cyclone Bulbul strengthened over the Bay of Bengal on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Bulbul was located at latitude 14.8°N and longitude 89.9°E which put it about 520 miles (840 km) south of Kolkata, India.  Bulbul was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 985 mb.

A low pressure system that was formerly designated at Tropical Storm Matmo when it was over the South China Sea moved across southeast Asia and over the Bay of Bengal during the past few days.  The low pressure system became nearly stationary west of the Andaman Islands.  More thunderstorms began to develop and bands began to form on Tuesday.  The low pressure system strengthened on Wednesday and the India Meteorological Department designated the system as Tropical Cyclone Bulbul.

The circulation around Tropical Cyclone Bulbul was still organizing on Wednesday night.  More thunderstorms were developing around the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Bulbul.  The stronger rainbands were in the western half of the circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center.

Tropical Cyclone Bulbul will move through an area favorable for intensification during the next 48 hours.  Bulbul 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 southeast Asia.  The ridge will produce southerly 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 Bulbul is likely to strengthen into the equivalent of a hurricane/typhoon within 36 to 48 hours.

The ridge over southeast Asia will steer Tropical Cyclone Bulbul toward the north during the next several days.  On its anticipated track Tropical Cyclone Bulbul will approach the coast around the northern Bay of Bengal in two or three days.  Bulbul could be the equivalent of a hurricane/typhoon when it approaches the coast.

Elsewhere, a much weaker Tropical Cyclone Maha neared the west coast of India.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Maha was located at latitude 20.0°N and longitude 70.2°E which put it about 75 miles (120 km) southwest of Dui, India.  Maha was moving toward the east-northeast 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.  Tropical Cyclone Maha will drop rain of southern Gujarat on Thursday.

Weakening Tropical Cyclone Maha Moves Back Toward India

A weakening Tropical Cyclone Maha moved back toward India on Tuesday.  At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Maha was located at latitude 19.8°N and longitude 66.7°E which put it about 425 miles (690 km) west of Mumbai, India.  Maha was moving toward the east at 15 m.p.h. (24 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 985 mb.

An upper level trough over southwest Asia was producing westerly winds which were blowing toward the top of Tropical Cyclone Maha.  Those winds were creating strong vertical wind shear which was causing Maha to weaken steadily.  Tropical Cyclone Maha weakened to the equivalent of a tropical storm on Tuesday night.  There was no longer an eye at the center of Maha.  Thunderstorms were forming in rainbands east of the center of circulation.  Bands in the other parts of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 75 miles (120 km) from the center of circulation.

The westerly winds were also steering Tropical Cyclone Maha back toward India.  On its anticipated track Maha could approach the coast of India between Mumbai and Diu in about 48 hours.  Tropical Cyclone Maha is likely to have weakened to the equivalent of a tropical depression by the time it nears the coast.

Vertical Wind Shear Starts to Weaken Tropical Cyclone Maha

Increased vertical wind shear started to weaken Tropical Cyclone Maha over the Arabian Sea on Monday night.  At 10:00 p.m. EST on Monday the center of Tropical Cyclone Maha was located at latitude 19.6°N and longitude 63.7°E which put it about 605 miles (1140 km) west of Mumbai, India.  Maha was moving toward the north at 2 m.p.h. (3 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 958 mb.

Upper level westerly winds of the middle latitudes moved southward over the northern Arabian Sea on Monday night.  Those winds caused increased vertical wind shear and they started to weaken Tropical Cyclone Maha.  The westerly winds began to push the higher clouds toward the east and the eye was no longer visible on infrared satellite imagery.  It also appeared that westerly winds lower in the atmosphere may have been transporting drier air toward the western side of Maha.  The rainbands in the western half of Tropical Cyclone Maha weakened on Monday night and there also appeared to be weakening in the southern part of the eyewall.  The strongest rainband was north of the center of circulation.

The circulation around Tropical Cyclone Maha was fairly small.  Winds to hurricane/typhoon force only extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 95 miles (150 km) from the center.  The small size of Tropical Cyclone Maha means it will weaken more quickly because of the effects of vertical wind shear and drier air.  Maha could weaken to the equivalent of a tropical storm within 24 to 30 hours.

The westerly winds will push Tropical Cyclone Maha back east toward India.  On its anticipated track Tropical Cyclone Maha could approach the coast of India north of Mumbai within three days.  Maha will be a much weaker tropical cyclone by the time it nears India.

Tropical Cyclone Maha Strengthens into Equivalent of a Major Hurricane

Tropical Cyclone Maha strengthened into the equivalent of a major hurricane on Sunday night.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Maha was located at latitude 18.2°N and longitude 64.8°E which put it about 525 miles (845 km) west of Mumbai, India.  Maha was moving toward the northwest at 4 m.p.h. (6 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 958 mb.

Tropical Cyclone Maha continued to intensify on Sunday and it became the equivalent of a major hurricane.  There was a small eye 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 Tropical Cyclone Maha.  The strongest rainbands were in the eastern half of the tropical cyclone.  Bands in the western half of Maha consisted primarily of showers and lower clouds.  Storms near the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Maha was relatively small.  Winds to hurricane/typhoon force extended out 20 miles (35 km) from the center of circulation.  Winds to tropical storm force extended out 75 miles (120 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Maha was 20.6.  The Hurricane Size Index (HSI) was 6.6 and the Hurricane Wind Intensity Size Index (HWISI) was 27.2.  Maha was capable of causing localized major damage.

Tropical Cyclone Maha will move through an environment favorable for intensification for another 12 to 18 hours.  Maha will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha may be pulling drier air into the western half of the circulation, which could be the reason for the lack of thunderstorms in that half of the circulation.  The drier air could prevent significant additional intensification if it gets pulled into the core of the circulation.  An upper level trough will approach Maha from the west in about 18 hours.  The trough will produce stronger westerly winds which will cause the vertical wind shear to increase.  Tropical Cyclone Maha will begin to weaken when the wind shear increases.

Tropical Cyclone Maha will move around the western end of a ridge of high pressure over India and the eastern Arabian Sea during the next 24 hours.  The ridge will steer Maha slowly toward the northwest.  When the upper level trough approaches Tropical Cyclone Maha, the westerly winds will steer the tropical cyclone back toward the east.  On its anticipated track Maha could approach the coast of India north of Mumbai in about 72 hours.

Tropical Cyclone Maha Strengthens to Equivalent of a Hurricane/Typhoon

Tropical Cyclone Maha strengthened into the equivalent of a hurricane/typhoon over the Arabian Sea west of India on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Maha was located at latitude 17.7°N and longitude 66.1°E which put it about 440 miles (705 km) west-southwest of Mumbai, India.  Maha was moving toward the west-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 997 mb.

The circulation around Tropical Cyclone Maha exhibited better organization on Saturday.  An eye formed at the center of Maha.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in the ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Maha.  The strongest rainbands were in the southern half of the circulation.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 65 miles (105 km) from the center.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next 36 to 48 hours.  Maha will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western portion of an upper level ridge where the winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha will continue to intensify and it could strengthen into the equivalent of a major hurricane during the n ext several days.

Tropical Cyclone Maha will move around the southwestern part of a ridge of high pressure over India and the eastern Arabian Sea.  The high will steer Maha toward the northwest during the next day or two.  An upper level trough will approach Tropical Cyclone Maha from the northwest in two or three days.  Westerly winds blowing around the southern end of the trough will turn Maha back toward the east.  On its anticipated track Tropical Cyclone Maha could approach the west coast of India north of Mumbai in about four days.

Tropical Cyclone Maha Reorganizes Southwest of Mumbai

Tropical Cyclone Maha reorganized over the Arabian Sea southwest of Mumbai, India on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Mumbai was located at latitude 16.2°N and longitude 68.8°E which put it about 320 miles (520 km) southwest of Mumbai, India.  Maha was moving toward the northwest at 7 m.p.h. (11 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 997 mb.

After pulling drier air from India into the circulation and weakening on Thursday, Tropical Cyclone Maha appeared to be reorganizing on Friday afternoon.  Many of the thunderstorms in the rainbands weakened on Thursday.  A band of strong thunderstorms reformed on Friday and it was wrapping around the southern and eastern sides of the center of circulation.  The inner end of the rainband was wrapping closer to the center of the circulation and an inner core appeared to be reforming.  Storms in the band started to generate upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 75 miles (120 km) from the center of circulation.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next 24 to 48 hours.  Maha will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha will intensify during the next day or two and it is likely to strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Maha will move south of a ridge of high pressure over South Asia.  The high will steer Maha toward the northwest during the next several days.  On its anticipated track Tropical Cyclone Maha will remain west of India during the weekend.

Elsewhere over the Arabian Sea,, Tropical Cyclone Kyarr meandered northeast of Somalia.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Kyarr was located at latitude 16.0°N and longitude 58.0°E whichput it about 355 miles (575 km) northeast of Socotra, Yemen.  Kyar was moving toward the southwest at 5 m.p.h. (8 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 1002 mb.

Tropical Cyclone Maha Forms Southwest of India

Tropical Cyclone Maha formed over the Arabian Sea southwest of India on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Maha was located at latitude 11.0°N and longitude 73.3°E which put it about 140 miles (225 km) southwest of Mangalore, India.  Maha was moving toward the northwest at 11 m.p.h. (17 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 997 mb.

More thunderstorms formed near the center of a low pressure over the Arabian Sea west of the southern tip of India on Wednesday and the India Meteorological Department designated the system as Tropical Cyclone Maha.  The circulation around Tropical Cyclone Maha was still organizing on Wednesday.  Bands of showers and thunderstorms were forming and the bands were starting to revolve around the center of Maha.  The strongest thunderstorms were occurring in bands in the western half of the circulation.  Some thunderstorms were also forming in bands in the eastern half of the tropical cyclone, but the proximity to southern India may have been making the air a little drier in that part of Maha.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next few days.  Maha will move over water where the Sea Surface Temperature is near 29°C.  It will move underneath the axis of an upper level ridge running east to west over India and the eastern Arabian Sea.  The upper level winds will be weak and there will not be a lot of vertical wind shear during the next day or two.  Tropical Cyclone Maha will continue to intensify and it is forecast to strengthen into the equivalent of a hurricane/typhoon.  Maha could strengthen more quickly once an inner core with an eye and an eyewall develop.

The middle portion of the upper level ridge will steer Tropical Cyclone Maha toward the northwest during the next 48 hours.  When Maha reaches the northern Arabian Sea a second ridge of high pressure over South Asia will steer the tropical cyclone toward the west.  On its anticipated track Tropical Cyclone Maha will move parallel to the west coast of India.

Elsewhere over the Arabian Sea, Tropical Cyclone Kyarr was weakening rapidly southeast of Oman.  The circulation pulled drier air from the Arabian peninsula into the core of Kyarr and most of the thunderstorms dissipated when the drier air reached them.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Kyarr was located at latitude 18.3°N and longitude 60.7°E which put it about 190 miles (305 km) southeast of Masirah Island, Oman.  Kyarr was moving toward the southwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 987 mb.

Tropical Cyclone Kyarr Weakens East of Oman

Tropical Cyclone Kyarr weakened east of Oman on Tuesday.  At 11:00 EDT on Tuesday the center of Tropical Cyclone Kyarr was located at latitude 19.5°N and longitude 62.0°E which put it about 220 miles (355 km) east-southeast of Masirah Island, Oman.  Kyarr was moving toward the west at 6 m.p.h. (10 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 954 mb.

The structure of the circulation around Tropical Cyclone Kyarr exhibited less organization on Tuesday.  The southwestern part of the ring of thunderstorms around the eye weakened.  In addition, bands of showers and thunderstorms in the western half of Kyarr also weakened.  Two factors seemed to be contributing to the weakening trend.  Tropical Cyclone Kyarr moved slowly during the last 24 to 36 hours.  The circulation mixed cooler water to the upper levels of the Arabian Sea and Kyarr was not able to extract as much energy from the water.  The circulation around Tropical Cyclone Kyarr may have pulled drier air from the Arabian peninsula into the western half of the circulation.  Even though Kyarr weakened on Tuesday. winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 130 miles (210 km) from the center.

Tropical Cyclone Kyarr will probably continue to weaken during the next several days.  Kyarr will move away from the cooler water it mixed to the surface and it will be in an area where there will not be a lot of vertical wind shear.  However, Tropical Cyclone Kyarr is likely to draw more drier air into the circulation.  The drier air will make it more difficult for thunderstorms to develop in rainbands around the tropical cyclone.

Tropical Cyclone Kyarr will move south of a ridge of high pressure over southwest Asia.  The high is forecast to strengthen during next several days.  When the high strengthens it will steer Kyarr toward the southwest.  On its anticipated track Tropical Cyclone Kyarr will move parallel to the coast of Oman.  Kyarr could approach Socotra Island and Somalia in four or five days.