Category Archives: Indian Ocean

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.

Intense Tropical Cyclone Kyarr Moves Toward Oman

Intense Tropical Cyclone Kyarr moved toward Oman on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Kyarr was located at latitude 18.3°N and longitude 65.2°E which put it about 460 miles (745 km) east-southeast of Masirah Island, Oman.  Kyarr was moving toward the west-northwest at 8 m.p.h. (13 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 932 mb.

The circulation around Tropical Cyclone Kyarr remained very symmetrical on Sunday.  Microwave satellite images seemed to indicate that there were two symmetric eye eyewalls surrounding the center of Kyarr.  Bands of showers and thunderstorms were revolving around the larger core of Tropical Cyclone Kyarr.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone in all directions.

The formation of a second, outer eyewall caused the circulation around Tropical Cyclone Kyarr to increase in size.  Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Kyarr was 31.6.  The Hurricane  Size Index (HSI) was 19.1 and the Hurricane Wind Intensity Size Index (HWISI) was 50.7.

The formation of concentric eyewalls indicated that an eyewall replacement cycle was in progress.  Tropical Cyclone Kyarr 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.  Even though Kyarr will move through an environment favorable for strong tropical cyclones, it will likely weaken while the inner eyewall dissipates.

Tropical Cyclone Kyarr will move south of a ridge of high pressure over South Asia.  The ridge will steer Kyarr in a westward direction during the next few days.  On its anticipated track Tropical Cyclone Kyarr could approach the coast of Oman in three or four days.

Tropical Cyclone Kyarr Strengthens to Equivalent of a Major Hurricane over Arabian Sea

Tropical Cyclone Kyarr strengthened to the equivalent of a major hurricane over the Arabian Sea on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Kyarr was located at latitude 16.9°N and longitude 68.6°E which put it about 705 miles (1135 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 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 944 mb.

Tropical Cyclone Kyarr intensified rapidly into the equivalent of a major hurricane during the past 36 hours.  A small eye formed 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 Kyarr.  Storms near the core of Kyarr were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.

The circulation around Tropical Cyclone Kyarr was very symmetrical.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) was 25.1.  The Hurricane Size Index (HSI) was 15.1 and the Hurricane Wind intensity Size Index (HWISI) was 40.2.

Tropical Cyclone Kyarr will move through an environment favorable for intensification during the next 12 to 24 hours.  Kyarr 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 Kyarr could strengthen during the next 24 hours.  An inner rainband could wrap around the eye and eyewall at some point.  That would start an eyewall replacement cycle which would cause Kyarr to weaken.

Tropical Cyclone Kyarr will move south of a ridge of high pressure over South Asia.  The ridge will steer Kyarr toward the west during the next few days.  On its anticipated track Tropical Cyclone Kyarr will move toward Oman.

Tropical Cyclone Forms Southwest of Mumbai

A tropical cyclone formed southwest of Mumbai, India on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone 04A was located at latitude 15.7°N and longitude 71.3°E which put it about 200 miles (320 km) southwest of Mumbai, India.  It was moving toward the north at 2 m.p.h. (3 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 997 mb.

A distinct low level center of circulation formed within a broad area of low pressure over the Arabian Sea west of India.  Thunderstorms were developing near the low level center.  Bands of showers and thunderstorms were forming and the bands began to revolve around the center of circulation.  Storms near the center started to generate upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out 105 miles (165 km) from the center of circulation.

Tropical Cyclone 04A will move through an environment favorable for intensification during the next 48 to 72 hours.  It will move over water where the Sea Surface Temperature is near 29°C.  The tropical cyclone will move through a region where the upper level wind are weak and there will be little vertical wind shear.  Tropical Cyclone 04A will continue to intensify and it is likely to strengthen into the equivalent of a hurricane/typhoon within 24 to 36 hours.

Tropical Cyclone 04A will move south of a high pressure system that extends from India across the northern Arabian Sea.  The high will steer the tropical cyclone in a west-northwesterly direction.  On its anticipated track Tropical Cyclone 04A should start to move away from India during the next 24 hours.  The tropical cyclone could approach Oman in about five days

Tropical Cyclone Hikaa Makes Landfall on Central Coast of Oman

Tropical Cyclone Hikaa made landfall on the central coast of Oman near Duqm on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Hikaa was located at latitude 19.6°N and longitude 56.4°W which put it about 85 miles (135 km) west of Duqm, Oman.  Hikaa was moving toward the west at 13 m.p.h. (20 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 981 mb.

Tropical Cyclone Hikaa was the equivalent of a hurricane/typhoon when it made landfall on the central coast of Oman.  Hikaa brought wind and rain to Masirah Island before it reached the coast of Oman.  Tropical Cyclone Hikaa brought strong winds and locally heavy rain to the coast near Duqm when it made landfall.  The circulation around Tropical Cyclone Hikaa was small.  Winds to tropical storm force only extended out 60 miles (95 km) from the center of circulation.  The small size of Hikaa will limit the potential for serious damage to locations close to the track of the tropical cyclone.

Tropical Cyclone Hikaa will drop heavy rain over portions of east-central Oman.  The rain could be heavy enough to cause flash floods in some locations.  Hikaa will weaken quickly as it moves into the drier environment over central Oman.  The small circulation around Tropical Cyclone Hikaa means that it will spin down fairly quickly now that it is over land.

Tropical Cyclone Hikaa Rapidly Intensifies to Equivalent of Hurricane/Typhoon East of Oman

Tropical Cyclone Hikaa rapidly intensified into the equivalent of a hurricane/typhoon over the northern Arabian Sea east of Oman on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Cyclone Hikaa was located at latitude 20.2°N and longitude 61.7°E which put it about 225 miles (365 km) east of Masirah Island.  Hikaa was moving toward the west at 13 m.p.h. (20 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 975mb.

Tropical Storm Hikaa intensified from the equivalent of a minimal tropical storm into the equivalent of a hurricane/typhoon in 24 hours.  A small eye developed quickly at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  The circulation around Tropical Cyclone Hikaa was very small.  Winds to hurricane/typhoon force extended out about 15  miles (25 km) from the center of circulation.  Winds to tropical storm force only extended out 45 miles (75 km) from the center.

Tropical Cyclone Hikaa may have reached its peak intensity.  Hikaa 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 atmospheric conditions will become less favorable.  An upper level ridge over southwestern Asia will produce easterly winds which will cause moderate vertical wind shear.  In addition, the circulation around Tropical Cyclone Hikaa will begin to draw drier air from eastern Africa into the circulation on Tuesday.  Since Hikaa is so small, the tropical cyclone could weaken quickly if the environment becomes less favorable.

The ridge over southwestern Asia will steer Tropical Cyclone Hikaa toward the west.  On its anticipated track Hikaa could approach the coast of Oman near Masirah Island in less than 18 hours.  Tropical Cyclone Hikaa will bring gusty winds and locally heavy rain to the central coast of Oman near Masirah Island.  Heavy rain could cause isolated flash floods.

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.