Category Archives: Indian Ocean

Tropical Cyclone Vayu Weakens South of Pakistan

Tropical Cyclone Vayu weakened over the Arabian Sea south of Pakistan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Vayu was located at latitude 24.2°N and longitude 65.3°E which put it about 275 miles (445 km) south-southwest of Karachi, Pakistan.  Vayu was moving toward the northwest at 8 m.p.h. (13 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.

The low level circulation around Tropical Cyclone Vayu remained well organized on Saturday, but the distribution of thunderstorms was asymmetrical.  The stronger thunderstorms were occurring in the southern half of the former eyewall and in several rainbands in the southern half of the circulation.  The strongest winds were occurring in the remaining portion of the eyewall.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 150 miles (240 km) from the center of circulation.

The circulation around Tropical Cyclone Vayu continued to draw drier air into the northern half of the tropical cyclone on Saturday.  An upper level ridge north of Vayu was producing strong northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear.  The drier air and wind shear were the primary factors causing the asymmetrical distribution of thunderstorms.

Tropical Cyclone Vayu will move through an environment unfavorable for intensification during the next 24 hours.  Even though Vayu will move over water where the Sea Surface Temperature is near 30°C, the combined effects of the drier air and the wind shear are likely to cause the tropical cyclone to continue to weaken on Sunday.  If the upper level winds get stronger, they could blow the upper half of the circulation southwest of the lower part of Tropical Cyclone Vayu.  In that case Vayu will weaken more quickly.

The future track of Tropical Cyclone Vayu will also depend on the vertical wind shear.  If the wind shear is not too strong and the circulation remains vertically intact, then the ridge north of Vayu will steer the tropical cyclone slowly toward the northwest on Sunday.  If the upper level winds blow the upper half of the circulation away from the lower portion of Tropical Cyclone Vayu, then southwesterly winds in the lower atmosphere will blow the shallower system toward the northeast.  Guidance from numerical models suggest this second scenario is more likely and the anticipated track takes Tropical Cyclone Vayu toward the northeast.

Tropical Cyclone Vayu Stalls, Weakens Southwest of Gujarat

Tropical Storm Vayu stalled and weakened southwest of Gujarat on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Vayu was located at latitude 20.6°N and longitude 67.4°E which put it about 170 miles (275 km) southwest of Dwarka, India.  Vayu was moving toward the west at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 969 mb.

The structure of the inner core of Tropical Cyclone Vayu changed significantly on Friday.  The previous small eye disappeared and a large new eye with a diameter of 50 miles (80 km) developed at the center of Vayu.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  The strongest rainbands were located in the southern half of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm extended out about 150 miles (240 km) from the center.

The environment around Tropical Cyclone Vayu will become less favorable for a tropical cyclone on Saturday.  An upper level ridge north of Vayu will strengthen.  The ridge will produce stronger northeasterly winds which will blow toward the top of the circulation.  Those winds will cause more vertical wind shear.  Tropical Cyclone Vayu will also continue to pull drier air into the northern half of the circulation.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  Even though Tropical Cyclone Vayu will be over very warm water, the combined effects of stronger wind shear and drier air are likely to cause it to weaken on Saturday.

The ridge north of Vayu will block the tropical cyclone from moving toward the north on Saturday.  The ridge is likely to continue to steer Tropical Cyclone Vayu slowly toward the west over the northeastern Arabian Sea during the next 24 hours.  On its anticipated track Vayu will move farther away from Gujarat and Pakistan on Saturday.

Tropical Cyclone Vayu Turns West Over Northeast Arabian Sea

Tropical Cyclone Vayu turned west over the northeastern Arabian Sea on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Vayu was located at latitude 20.9°N and longitude 68.4°E which put it about 80 miles (130 km) southwest of Porbandar, India.  Vayu was moving toward the west-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 960 mb.

Tropical Cyclone Vayu maintained its intensity on Thursday, but the circulation exhibited slightly less organization.  A small eye continued to mark the center of circulation.  A ring of strong thunderstorms surrounded the eye, but there was a break in the northeastern portion of the ring.  The circulation continued to pull drier air into the northern part of the tropical cyclone.  Many of the stronger thunderstorms were occurring in bands in the southern half of the circulation.  Rainbands in the northern half of the circulation were weaker.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 125 miles (200 km) from the center.

Tropical Cyclone Vayu will continue to move through an environment capable of sustaining a tropical cyclone on Friday.  Vayu will move under the axis of an upper level ridge where the winds are weaker and there will be little vertical wind shear.  The Sea Surface Temperature in the northeastern Arabian Sea is near 30°C.  However, Tropical Cyclone Vayu moved slowly on Thursday and it may have stirred some cooler water to the surface.  In addition, the circulation around Vayu will continue to draw in drier air from over south Asia.  Tropical Cyclone Vayu could start to weaken slowly on Friday, although it could maintain its intensity if it moves away from the upwelled cooler water.

Tropical Cyclone Vayu will be south of a strengthening ridge of high pressure over south Asia.  The ridge will block Vayu and prevent it from moving farther toward the north.  The ridge will steer Vayu slowly toward the west during the next 24 to 48 hours.  On its anticipated track Tropical Cyclone Vayu will remain southwest of Gujarat and south of Pakistan during the next two days.

Tropical Cyclone Vayu Slows Near Gujarat Coast

Tropical Cyclone Vayu slowed near the coast of Gujarat on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Vayu was located at latitude 20.4°N and longitude 69.1°E which put it about 85 miles (135 km) south-southwest of Porbandar, India.  Vayu was moving toward the north-northwest at 8 m.p.h. (13 km/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 962 mb.

The circulation around Tropical Cyclone Vayu weakened slightly on Wednesday, although the inner core appeared to remain mostly intact.  The circulation seemed to pull some drier air over India into the eastern and northern portions of Vayu.  Outer rainbands weakened in those parts of the tropical cyclone.  The drier air did not appear to have penetrated the inner core of the circulation.  A tiny eye remained at the center of circulation.  A ring of showers and thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of strong thunderstorms in the southern half of the circulation were revolving around the core of Tropical Cyclone Vayu.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 120 miles (195 km) from the center.

Tropical Cyclone Vayu will move through an environment that will be mainly favorable for a tropical cyclone during the next 24 to 48 hours.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  It will move near the axis of an upper level ridge where winds are weaker and there will be less vertical wind shear.  The drier air being pulled into the circulation from over India will be a factor that could inhibit any additional strengthening of Tropical Cyclone Vayu.  Vayu could strengthen during the next 24 hours, but it is more likely to maintain its intensity or weaken slightly.  If drier air mixes into the inner core of the circulation, then Tropical Cyclone Vayu could weaken more quickly.

Tropical Cyclone Vayu will move around the western end of a ridge over India during the next 12 to 24 hours.  The ridge will steer Vayu toward the north-northwest on Thursday.  A second ridge will develop north of Tropical Cyclone Vayu.  The second ridge will block the northward movement of Vayu and force the tropical cyclone to move more toward the west.  On its anticipated track the core of Tropical Cyclone Vayu will remain west of the coast of Gujarat.  Bands on the eastern side of the circulation could drop rain over Gujarat but the strongest part of the circulation is likely to remain offshore.

Tropical Cyclone Vayu Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Vayu strengthened into the equivalent of a hurricane/typhoon over the eastern Arabian Sea on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Vayu was located at latitude 16.4°N and longitude 70.8°E which put it about 200 miles (320 km) southwest of Mumbai, India.  Vayu was moving toward the north at 10 m.p.h. (16 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. (150 km/h).  The minimum surface pressure was 974 mb.

Microwave satellite imagery indicated that an inner rainband had wrapped completely around the center of circulation and a small eye had formed at the center of Tropical Cyclone Vayu.  The core of Vayu was relatively small.  Winds to hurricane/typhoon force only extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.  Storms around the core of Tropical Cyclone Vayu were generating upper level divergence which was pumping mass to the west of the tropical cyclone.  Additional bands of showers and thunderstorms were revolving around the core of Vayu.

Tropical Cyclone Vayu will move through an environment favorable for intensification during the next 24 to 36 hours.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone Vayu will move near the southwestern portion of an upper level ridge.  The ridge will produce southeasterly 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 Vayu will intensify during the next 24 to 36 hours.  It could intensify rapidly once the eye and eyewall are fully formed.  Vayu could strengthen into the equivalent of a major hurricane.

Tropical Cyclone Vayu will move around the western end of a ridge over India.  The ridge will steer Vayu toward the north.  On its anticipated track Tropical Cyclone Vayu could approach the coast of Gujarat within 36 hours.  Vayu could be the equivalent of a major hurricane by that time.  It could bring strong winds and locally heavy rain to Gujarat.  Heavy rain could cause flash floods.  Tropical Cyclone Vayu could also generate a significant storm surge along the coast of Gujarat.

Tropical Cyclone Forms Over Eastern Arabian Sea

A tropical cyclone formed over the eastern Arabian Sea on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Cyclone 02A was located at latitude 13.7°N and longitude 70.8°E which put it about 400 miles (645 km) south-southwest of Mumbai, India.  It was moving toward the north-northwest at 10 m.p.h. (16 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.

More thunderstorms formed near the center of a low pressure system over the eastern Arabian Sea on Monday and the system exhibited sufficient organization to be designated a tropical cyclone.  The distribution of thunderstorms around the tropical cyclone was asymmetrical.  Most of the stronger thunderstorms were located in bands developing in the western half of the circulation.  The inner portions of a rainband was wrapping around the southern side of the center of circulation.  Bands in the eastern half of the circulation consisted primarily of lower clouds and showers.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone 02A developed southwest of an upper level ridge.  The ridge was producing easterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were the primary cause for the asymmetrical distribution of thunderstorms.  The tropical cyclone will move over water where the Sea Surface Temperature is near 30°C.   Wind shear will inhibit intensification, but it will not be strong enough to prevent Tropical Cyclone 02A from strengthening.  The tropical cyclone will gradually intensify and it could strengthen to the equivalent of a hurricane/typhoon.  If an eye and eyewall form as part of an inner core and the wind shear decreases, then a period of rapid intensification could occur.

Tropical Cyclone 02A will move around the western end of the upper level ridge.  The ridge will steer the tropical cyclone toward the north-northwest during the next several days.  On its anticipated track Tropical Cyclone 02A could approach the coast of Gujarat within 72 hours.  it could be the equivalent of a hurricane/typhoon by that time.

Tropical Cyclone Ann Forms Over Coral Sea

Tropical Cyclone Ann formed over the Coral Sea on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Ann was located at latitude 16.3°S and longitude 158.7°E which put it about 875 miles (1410 km) east of Cairns, Australia.  Ann was moving toward the west 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 999 mb.

A distinct low level center of circulation became more evident in satellite images of a low pressure system over the eastern Coral Sea on Saturday and the system was designated as Tropical Cyclone Ann.  A rainband wrapped around the southern and western sides of the center of circulation.  A microwave satellite image indicated that the band may have wrapped completely around the center in the middle levels of the circulation.  Storms near the center of circulation began to generate upper level divergence which was pumping mass away from the tropical cyclone.  The circulation around Tropical Cyclone Ann was relatively small.  Winds to tropical storm force extended out about 85 miles (135 km) from the center of circulation in the southern half of Ann.

Tropical Cyclone Ann will move through an environment somewhat favorable for intensification during the next day or two.  Ann will move over water where the Sea Surface Temperature is near 28.5°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will cause some vertical wind shear.  The shear will inhibit intensification, but it is not likely to be strong enough to prevent intensification.  Tropical Cyclone Ann is likely to intensify during the next 24 hours.

The ridge will steer Tropical Cyclone Ann toward the west-northwest during the next two to three days.  On its anticipated track Tropical Cyclone Ann will approach the Cape York Peninsula in northern Queensland in about 72 hours.  Ann could bring gusty winds and locally heavy rain.

Elsewhere around the tropics in the southern hemisphere, Tropical Cyclone Lili was weakening near the coast of East Timor.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 126.8°E which put it about 120 miles (195 km) east-northeast of Suai, East Timor.  Lili was moving toward the west at 4 m.p.h. (6 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 1000 mb.

Tropical Cyclone Lili Forms Over Timor Sea

Tropical Cyclone Lili formed over the Timor Sea on Thursday.  At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 128.8°E which put it about 100 miles (160 km) southeast of Tutuala, East Timor.  Lili was moving toward the south-southwest at 5 m.p.h. (8 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 991 mb.

The circulation around a low pressure system over the Timor Sea exhibited more organization on Thursday and the system was designated as Tropical Cyclone Lili.  Several bands of showers and thunderstorms began to wrap around the low level center of circulation.  Additional bands of showers and thunderstorms began to develop around the periphery of the circulation.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.   The circulation around Tropical Cyclone Lili was relatively small.  Winds to tropical storm force only extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone Lili will move through an environment favorable for intensification during the next 12 to 24 hours.  Lili will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western portion of an upper level ridge.  Tropical Cyclone Lili will move through an area where the upper level winds are not too strong during the next 12 to 24 hours and there will not be a lot of vertical wind shear.  Lili could intensify during that period.  Tropical Cyclone Lili will move closer to the western end of the ridge in about 24 hours.  There are strong northerly winds blowing around the western end of the ridge and there will be more vertical wind shear.  If the shear increases, then the circulation around Lili is likely to weaken.

Tropical Cyclone Lili will move north of a subtropical ridge.  The ridge is likely to steer Lili more toward the west.  On its anticipated track Tropical Cyclone Lili could reach East Timor in about 36 hours.  Lili will bring gusty winds, but heavy rain and flooding are greater risks.  An alternative forecast scenario is possible.  If the vertical wind shear is not too strong and the vertical structure of Tropical Cyclone Lili remains intact, the upper level ridge could steer Lili more toward the south.  In that case Tropical Cyclone Lili could bring rain to Western Australia.

Powerful Tropical Cyclone Fani Makes Landfall in India

Powerful Tropical Cyclone Fani made landfall near Puri, India on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Fani was located at latitude 19.4°N and longitude 85.8°E which put it about 25 miles (40 km) south of Puri, India.  Fani was moving toward the north-northeast at 11 m.p.h. (17 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 922 mb.

Tropical Cyclone Fani is a large dangerous system.  Winds to hurricane/typhoon force extend out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extend out about 225 miles (360 km) from the center over the Bay of Bengal.  The Hurricane Intensity Index (HII) for Tropical Cyclone Fani is 31.6.  The Hurricane Size Index (HSI) is 25.6 and the Hurricane Wind Intensity Size Index (HWISI) is 57.2.  Tropical Cyclone Fani has the potential to cause widespread significant damage.

Tropical Cyclone Fani will cause the greatest wind damage along the northeast coast of Odisha.  It could also produce a significant storm surge along the coast.  The surge will be highest in bays, estuaries and mouths of rivers.  Fani will drop heavy rain over northeast Odisha, West Bengal and portions of Bangladesh.  The heavy rain is likely to cause inland fresh water floods in some locations.  Wind and rain could cause damage around Kolkata (Calcutta), India.

An upper level trough over India will steer Tropical Cyclone Fani toward the northeast during the next 48 hours.  On its anticipated path Fani will pass near Bhubaneshwar, Cuttack and Baleshwar in Odisha.  Tropical Cyclone Fani could still be the equivalent of a hurricane/typhoon when it passes near those locations.  Fani will weaken steadily while it moves northeast.  It is likely to be the equivalent of a tropical storm when it passes near Kolkata.  Tropical Cyclone Fani will weaken to the equivalent of a tropical depression when it passes over Bangladesh, but it could still drop heavy rain around Dhaka.  Serious flooding could occur in Bangladesh while Fani weakens.

Dangerous Tropical Cyclone Fani Near Northeast India

Dangerous Tropical Cyclone Fani neared the coast of northeastern India on Thursday.  Fani rapidly intensified into the nearly the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Fani was located at latitude 18.0°N and longitude 84.9°E which put it about 100 miles (160 km) east of Visakhapatnam, India.  Fani was moving toward the north at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 918 mb.

Tropical Cyclone Fani intensified rapidly during recent hours.  A circular eye with a diameter of 20 miles (32 km) developed at the center of circulation.  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 Tropical Cyclone Fani.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Fani grew larger as it intensified.  Winds to hurricane/typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 185 miles (295 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Fani was 33.3.  The Hurricane Size Index (HSI) was 21.7 and the Hurricane Wind Intensity Size Index (HWISI) was 55.0.  Tropical Cyclone Fani was capable of causing widespread significant damage.

Tropical Cyclone Fani is moving around the western end of a subtropical ridge.  The ridge is steering Fani toward the north.  On its anticipated track Tropical Cyclone Fani is likely to make landfall near Brahmapur, India in about 12 hours.  An upper level trough over India will steer Fani toward the northeast after it makes landfall.  Tropical Cyclone Fani could pass near Puri, Bhubaneswar, Cuttack and Kolkata (Calcutta), India.

Tropical Cyclone Fani will remain in a favorable environment during the 12 hours prior to landfall.  Fani will be over water where the Sea Surface Temperature is near 30°C.  It will move through an environment where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Fani will weaken after landfall.  The upper level trough over India will produce stronger southwesterly winds, which will increase the vertical wind shear after Fani makes landfall.  More wind shear and more friction over the land will cause Tropical Cyclone Fani to weaken to the equivalent of a tropical storm within 24 hours after landfall occurs.

Tropical Cyclone Fani is a dangerous tropical cyclone.  The strengthen and size of Fani will create the potential for widespread significant damage.  The counterclockwise circulation will cause the winds to blow water toward the coast along the northern Bay of Bengal.  Tropical Cyclone Fani could generate a storm surge of 15 to 20 feet (4.5 to 6.0 meters) in bays, estuaries and the mouths of rivers which act as funnels during storm surges.  Heavy rain could cause inland fresh water flooding in parts of northeastern India and Bangladesh.  The greatest threats are to the Indian states of Odisha (Orissa) and West Bengal.