Tag Archives: Sri Lanka

Tropical Cyclone Fani Develops East of Sri Lanka

Tropical Cyclone Fani developed over the southern Bay of Bengal east of Sri Lanka on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Fani was located at latitude 7.8°N and longitude 88.6°E which put it about 635 miles (1020 km) east-southeast of Chennai, India.  Fani was moving toward the north-northwest at 15 m.p.h. (24 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 989 mb.

A distinct low level center of circulation formed on the eastern side of a cluster of thunderstorms over the southern Bay of Bengal on Saturday and the India Meteorological Department designated the system as Tropical Cyclone Fani.  The circulation around Fani was still organizing.  Bands of showers and thunderstorms were developing.  Many of the stronger thunderstorms were developing in two clusters which were east and northwest of the center of circulation.  Bands in other parts of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 100 miles (160 km) from the center of circulation.

Tropical Cyclone Fani will move into an environment that is more favorable for intensification.  Fani is currently under the southern part of an upper level ridge.  The ridge is producing easterly winds which are causing moderate vertical wind shear.  The wind shear is the primary factor slowing the intensification of Tropical Cyclone Fani.  Fani is forecast to move under the axis of the ridge where the upper level winds are weaker.  There will be less vertical wind shear when that happens.  Tropical Cyclone Fani will move over water where the Sea Surface Temperature is near 31°C.  So, intensification is very likely when the wind shear decreases.  Fani is likely to strengthen into the equivalent of a hurricane/typhoon.  Rapid intensification could occur if the inner core of the circulation becomes more well developed.

Tropical Cyclone Fani will move around the western end of a subtropical ridge over southeast Asia.  The ridge will steer Fani toward the north-northwest during the next several days.  It will move more toward the north when it moves around the western end of the ridge.  On its anticipated track Tropical Cyclone Fani will move toward the northern Bay of Bengal.

Tropical Cyclone Ockhi Strengthens Quickly Southwest of India

Tropical Cyclone Ockhi strengthened quickly southwest of India on Thursday.  At 7:00 a.m. EST on Thursday the center of Tropical Cyclone Ockhi was located at latitude 8.0°N and longitude 76.2°E which put it about 810 miles (1305 km) south-southeast of Mumbai, India.  Ockhi was moving toward the west-northwest at 10 m.p.h. (16 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 988 mb.

The core of the circulation of a tropical depression that developed near Sri Lanka on Wednesday organized quickly on Thursday.  A primary rainband wrapped most of the way around the center of circulation and an eye began to appear on some satellite imagery.  The storms in the eyewall were strongest west of the eye and weakest north of the eye.  Additional bands of showers and thunderstorms formed outside the core of the circulation.  Thunderstorms in the core of Ockhi generated strong upper level divergence which was pumping mass away to the north and west of the tropical cyclone.  The divergence was allowing the surface pressure to decrease and the wind speeds to increase.

Tropical Cyclone Ockhi will be moving through an environment favorable for intensification during the next several days.  Ockhi will move over water where the Sea Surface Temperature is near 29°C.  Tropical Cyclone Ockhi is near the western end of an upper level ridge.  The ridge is producing southeasterly winds which are blowing toward the top of the circulation.  Those winds are causing some vertical wind shear, but they are also enhancing the upper level divergence to the north and west of Tropical Cyclone Ockhi.  The positive effects of enhanced divergence will exceed the negative effects of the vertical wind shear.  Tropical Cyclone Ockhi will continue to intensify and it could intensify rapidly.  Ockhi will likely become the equivalent of a hurricane/typhoon within the next 24 hours.

The upper level ridge is currently steering Tropical Cyclone Ockhi toward the west-northwest.  Ockhi will turn more toward the north in a day or two when it reaches the western end of the ridge.   On its anticipated track Tropical Cyclone Ockhi will move farther away from the coast of India during the next 24 to 48 hours.  The outer rainbands on the eastern side of Ockhi will drop locally heavy rain over portions of southern India and flash floods could occur in some places.  Tropical Cyclone Ockhi is likely to turn toward the northeast in three or four days and it could eventually make landfall in western India.

Tropical Depression Forms Near Southern Tip of Sri Lanka

A tropical depression formed near the southern tip of Sri Lanka on Wednesday.  At 7:00 a.m. EST on Wednesday the center of Tropical Depression 96S was located at latitude 6.2°N and longitude 80.0°E which put it about 20 miles (30 km) northwest of Galle, Sri Lanka.  It was moving toward the west-southwest at 4 m.p.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.

A center of circulation formed within a cluster of thunderstorms also designated as Invest 91B and the Indian Meteorological Department classified the system as a Depression.  The circulation in the tropical depression was still organizing.  A large, primary rainband wrapped around the southern and western sides of the center of circulation.  Additional bands of showers and strong thunderstorms were forming in the western half of the circulation.  Bands of showers and isolated thunderstorms were developing in the eastern half of the circulation.  Thunderstorms in the primary rainband were generating upper level divergence which was pumping away mass to the west of the depression.

The depression will move through an environment favorable for intensification during the next several days.  It will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge over India is generating easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear which is probably the reason why most of the stronger thunderstorms are occurring in the western half of the depression.  The vertical wind shear will inhibit intensification, but it is not likely to prevent strengthening.  The depression is likely to intensify into a stronger tropical cyclone during the next several days.

The ridge over India is steering the tropical depression toward the west-southwest.  The ridge is forecast to steer the depression in a generally westerly direction during the next several days.  On its anticipated track the depression will move away from Sri Lanka and the center will pass south of India.  The depression could cause locally heavy rain and flash floods in parts of Sri Lanka and southern India.

Tropical Cyclone Vardah Nearing Landfall in India

Tropical Cyclone Vardah moved steadily toward a landfall near Chennai India on Sunday.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Vardah was located at latitude 13.2°N and longitude 81.1°E which put it about 60 miles (105 km) east of Chennai, India.  Vardah was moving toward the west at 10 m.p.h. (16 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 967 mb.

The Indian Meteorological Department’s radar at Chennai shows that Tropical Cyclone Vardah is very well organized and symmetrical.  There is a circular eye surrounded by a ring of strong thunderstorms.  The strongest storms are west and south of the eye, and the ring is thinner east of the eye.  There are multiple bands of thunderstorms and the heaviest thunderstorms in those bands are also in the western half of the circulation.  The thunderstorms are generating strong upper level divergence which is pumping out mass to the west and north of the tropical cyclone.

Tropical Cyclone Vardah is moving over water where the Sea Surface Temperature is near 29°C.  The energy from the ocean will keep Vardah from weakening before it makes landfall.  Tropical Cyclone Vardah will weaken steadily once it begins to move over southern India.

A subtropical ridge north of Vardah is steering the tropical cyclone toward the west and that general motion is expected to continue.  On its anticipated track Tropical Cyclone Vardah will make landfall near Chennai, India in a few hours.  Vardah will continue to move west across southern India after it moves inland.

Tropical Cyclone Vardah will bring strong winds and heavy rain to the area around Chennai.  The Hurricane Intensity Index (HII) is 12.7.  The Hurricane Size Index (HSI) is 11.3 and the Hurricane Wind Intensity Size Index (HWISI) is 24.0.  Those indices indicate that Tropical Cyclone Vardah is capable of causing regional minor wind damage when it makes landafall.

Vardah will also generate a storm surge along portion of the coast north of Chennai where the wind will blow the water toward the coast.  Vardah will produce locally heavy rain over Tamil Nadu, Andhra Pradesh and Karnataka.  The heavy rain could produce floods and mudslides.

Tropical Cyclone Vardah Reaches Hurricane Intensity

Tropical Cyclone Vardah intensified into the equivalent of a hurricane on Saturday as it moved across the Bay of Bengal toward India.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Vardah was located at latitude 13.0°N and longitude 84.8°E which put it about 290 miles (470 km) east of Chennai, India.  Vardah was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 974 mb.

The circulation of Tropical Cyclone Vardah is well organized, but the distribution of thunderstorms is asymmetrical.  There is a broken ring of thunderstorms around the center of circulation.  Outside of that ring most of the thunderstorms are forming in the western half of the circulation.  It appears that an upper level ridge to the north of Vardah is producing easterly winds which are causing moderate vertical wind shear.  The wind shear seems to be the primary cause of the asymmetry of the convection.  The thunderstorms are generating upper level divergence which is pumping out mass to the west of the cyclone.

The environment around Tropical Cyclone Vardah is marginal for further intensification.  Vardah is moving over water where the Sea Surface Temperature is near 29°C.  However, the moderate vertical wind shear may be strong enough to inhibit further intensification.  There are some indications that the upper level winds may be getting stronger and the shear could increase.  If the shear increases, then Tropical Cyclone Vardah could start to weaken even though it is over warm water.

The same ridge that is causing the wind shear is also steering Tropical Cyclone Vardah toward the west and that general motion is expected to continue.  On its anticipated track Tropical Cyclone Vardah could make landfall near Chennai, India in about 36 hours.  Tropical Cyclone Vardah will bring gusty winds and locally heavy rain to portions of southern India.  The heavy rain could cause flooding and mudslides.  Vardah will also cause a storm surge along the coast near and to the north of where the center makes landfall.

Tropical Cyclone Vardah Turns Toward India and Strengthens

Tropical Cyclone Vardah turned toward India and strengthened on Friday.  At 4:00 p.m. EDT on Friday the center of Tropical Cyclone Vardah was located at latitude 12.5°N and longitude 88.7°E which put it about 500 miles (800 km) southeast of Visakhapatnam, India.  Vardah was moving toward the west-northwest at 13 m.p.h. (21 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.

Many more thunderstorms formed around the core of Tropical Cyclone Vardah and it exhibited a more symmetrical, circular shape on Friday.  The increasing organization of the circulation include multiple spiral rainbands in the outer portions of the cyclone.  The thunderstorms near the core of Vardah generated strong upper level divergence which pumped out mass and allowed the pressure to decrease more quickly.  An increased pressure gradient force generated stronger winds.

The environment around Tropical Cyclone Vardah has become much more favorable for intensification.  An upper level ridge to the east of Vardah was causing southeasterly winds and was producing moderate vertical wind shear.  Those winds have diminished and the wind shear is much less.  Since Vardah is moving over water where the Sea Surface Temperature is near 29°C, it is efficiently extracting energy from the ocean.  Tropical Cyclone Vardah will continue to intensify during the next 24 hours and it could intensify rapidly.  Vardah is likely to become the equivalent of a hurricane on Saturday.

A subtropical ridge north of Vardah is strengthening and building toward the west.  The ridge is steering Tropical Cyclone Vardah toward the west-northwest and that general motion is expected to continue.  On its anticipated track Tropical Cyclone Vardah could approach the coast of southeast India in two or three days.

Tropical Cyclone Vardah could bring strong winds and heavy rain to parts of southeastern India in three or four days.

Tropical Cyclone Nada Develops Near Sri Lanka

Tropical Cyclone Nada developed over the Bay of Bengal near Sri Lanka.  At 10:00 a.m. EDT on Wednesday the center of Tropical Cyclone Nada was located at latitude 10.1°N and longitude 83.5°E which put it about 295 miles (475 km) east-southeast of Chennai, India.  Nada was moving toward the west-northwest at 14 m.p.h. (23 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.

Microwave satellite imagery indicates that Tropical Cyclone Nada has a well organized, circular low level circulation.  However, most of the thunderstorms are occurring in bands southwest of the center and north of the center.  There are mostly low clouds and showers in the circular bands south and east of the center of circulation.  An upper level ridge over the northern Bay of Bengal is producing easterly winds which are causing moderate vertical wind shear.  The upper level easterly flow is inhibiting the development of thunderstorms east of the center of Tropical Cyclone Nada and those winds may be tilting the circulation toward the west.

The environment surround Tropical Cyclone Nada consists of factors that are favorable for intensification and factors that are unfavorable.  Tropical Cyclone Nada is moving over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy in the upper ocean to support intensification.  However the easterly winds in the upper levels are restricting upper level divergence to the east of the tropical cyclone.  Moderate vertical wind shear will limit intensification unless the upper level winds weaken.  If the upper level winds do weaken, then Nada could strengthen given its well developed low level circulation.  Tropical Cyclone Nada only has about 24 to 30 hours before it reaches the coast of India and it will start to weaken once it moves over land.

A subtropical ridge north of Nada is steering the tropical cyclone toward the west-northwest and that general motion is expected to continue.  On its anticipated track the center of Tropical Cyclone Nada will pass north of Sri Lanka and it will approach the southeast coast of India in 24 to 30 hours.  Nada is likely to make a landfall south of Cheannai, India near Pondicherry.  Tropical Cyclone Nada is expected to continue to move to the west and it could emerge over the Arabian Sea in two or three days.

Tropical Cyclone Nada will bring gusty winds and locally heavy rain to northern Sri Lanka and southern India.  Locally heavy rain could cause flooding and mudslides in parts of northern Sri Lanka and Tamil Nadu, Kerala and Karnataka states in India.

Tropical Cyclone 01B Forms Over Bay of Bengal

The structure of a low pressure system north of Sri Lanka changed on Wednesday and it was classified as Tropical Cyclone 01B (TC01B).  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 01B was located at latitude 15.9°N and longitude 82.3°E which put it about 155 miles (250 km) south-southwest Visakhapatnam, India.  TC01B was moving toward the northeast at 12 m.p.h. (19 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 989 mb.

A low pressure system developed near Sri Lanka several days ago.  The low moved over the east coast of Sri Lanka, which slowed the organization of the circulation.  A more well defined center of circulation began to organize after the low moved north of Sri Lanka.  A primary rainband started to wrap around the western side of the low and several broken spiral bands formed on the eastern side.  The circulation exhibited enough characteristics associated with tropical cyclones to be classified as Tropical Cyclone 01B.

The circulation of TC01B is still not particularly well organized.  A primary rainband curls around the northern and western sides of the circulation.  However, there are not many thunderstorms in the other parts of the tropical cyclone.  An upper level ridge over the northern Bay of Bengal is generating easterly winds over the top of the tropical cyclone.  Those winds are producing moderate vertical wind shear and are contributing to the fact that most thunderstorms are west of the center of circulation.  The fact that the center of circulation is near the coast of India also means a  portion of circulation is over land, where there is more friction and less moisture.

Tropical Cyclone 01B is expected to move into a more favorable environment during the next two days.  It is over water where the Sea Surface Temperature is near 31°C.  TC01B is expected to move closer to the center of the upper level ridge where the winds are not as strong.  That would reduce the vertical wind shear, which would also be favorable for intensification.  However, the proximity of the center to the east coast of India means that a portion of the circulation will remain over land, which will slow the rate of future intensification.

A ridge is east of TC01B is expected to steer the tropical cyclone toward the northeast during the next two to three days.  On its anticipated track, TC01B could be approaching the coast of Bangladesh in 48 to 72 hours.  TC01B caused heavy rain in parts of Sri Lanka and southeast India.  It could produce more heavy rain in parts of northeast India, Bangladesh and Myanmar (Burma).  TC01B could also generate a significant storm surge along the north coast of the Bay of Bengal as it nears the coast.