Category Archives: Indian Ocean

Stronger Tropical Cyclone Mora Near Landfall in Bangladesh

A stronger Tropical Cyclone Mora neared landfall between Cox’s Bazar and Chittagong, Bangladesh.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Mora was located at latitude 21.8°N and longitude 91.9°E which put it about 90 miles (145 km) south of Chittagong, Bangladesh.  Mora was moving toward the north at 18 m.p.h. (29 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 974 mb.  Tropical Cyclone Mora was the equivalent of a hurricane/typhoon.

The inner core of Tropical Cyclone Mora organized quickly on Monday.  The primary rainband wrapped entirely around the center of circulation and an eye formed.  Additional bands of showers and thunderstorms were revolving around the core Tropical Cyclone Mora.  Thunderstorms near the core of Mora generated strong upper level divergence which pumped out mass and allowed the surface pressure to decrease.  The decrease of pressure caused the surface winds to increase to hurricane/typhoon intensity.  Winds to hurricane/typhoon strength extended out about 25 miles (40 km) from the center.  Winds to tropical storm force extended out about 150 miles (240 km) from the center.  The strongest winds were occurring in the eyewall and over the Bay of Bengal.

Tropical Cyclone Mora is moving around the western end of a subtropical ridge.  The ridge is steering Mora toward the north and that general motion is expected to continue for another 12 to 18 hours.  On its anticipated track the center of Tropical Cyclone Mora will move near the coast of Bangladesh between Cox’s Bazar and Chittagong.  The center is likely to make landfall near Chittagong during the next few hours.

The recent intensification of Tropical Cyclone Mora has made it a more dangerous storm.  The increased wind speed will increase the potential for wind damage.  In addition, stronger winds will increase the height of the storm surge along the coast.  A storm surge of 6 to 9 feet (2 to 3 meters) will be possible along the coast between Cox’s Bazar and Chittagong.  The increase in organization of the core has also created the potential for heavier rain and greater fresh water flooding of rivers and streams.

Tropical Cyclone Mora will start to weaken after the center makes landfall.  However, it will continue to generate areas of heavy rain while it moves inland over Bangladesh and northeastern India.

 

Tropical Cyclone Mora Intensifies As It Nears Bangladesh

Tropical Cyclone Mora intensified on Sunday as it moved closer to Bangladesh.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Mora was located at latitude 17.4°N and longitude 90.9°E which put it about 370 miles (595 km/h) south of Chittagong, Bangladesh.  Mora was moving toward the north at 9 m.p.h. (15 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 structure of Tropical Cyclone Mora exhibited more organization on Sunday.  A primary rainband wrapped about two thirds of the way around northern and western sides of the circulation.  A tighter center of circulation was evident at the core of Tropical Cyclone Mora.  There were few thunderstorms east of the center of circulation.  The thunderstorms in the primary rainband were generating more upper level divergence which was pumping out mass to the west and north of the tropical cyclone.  The divergence was causing the surface pressure to decrease and was contributing the increase in wind speed.

Tropical Cyclone Mora will move through an environment that will be favorable for additional strengthening during the next 24 hours.  Mora will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of Mora is generating easterly winds that are blowing toward the top of the circulation.  The easterly winds are generating moderate vertical wind shear and they are probably responsible for the location of the primary rainband north and west of the center of circulation.  The vertical shear will slow the rate of intensification, but it will not prevent Tropical Cyclone Mora from intensifying further.  Mora could intensify into the equivalent of a hurricane/typhoon before it makes landfall.

Mora was being steered toward the north by a subtropical ridge located to the east of the tropical cyclone.  A general northward motion is expected to continue for another 24 to 36 hours.  On its anticipated track Tropical Cyclone Mora will approach the coast of Bangladesh in 18 to 24 hours.

Tropical Cyclone Mora could make landfall near Chittagong, Bangladesh.  Mora will bring gusty winds to Bangladesh and northwestern Myanmar.  It will produce locally heavy rain and create a risk for fresh water flooding.  Counterclockwise rotation will push water toward the coast and there could be a storm surge near and to the east of where the center makes landfall.  The surge could increase the water level at the coast by 6 to 8 feet (2 to 3 meters).

Tropical Cyclone 02B Forms Over the Bay of Bengal

A surface circulation formed over the Bay of Bengal on Saturday and the system was designated Tropical Cyclone 02B.  At 8:00 p.m. EDT on Saturday the center of Tropical Cyclone 02B was located at latitude 14.2°N and longitude 88.9°E which put it about 640 miles (1030 km) south-southwest of Chittagong, Bangladesh.  The tropical cyclone was moving toward the north-northeast at 4 m.p.h. (6 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 998 mb.

A low level center of circulation consolidated over the Bay of Bengal on Saturday.  The distribution of thunderstorms was asymmetrical.  Most of the thunderstorms in the inner part of the circulation developed west of the center.  There were some thunderstorms in outer bands northeast of the center, but there were few thunderstorms closer to the core of the circulation in the eastern half of the tropical cyclone.  The thunderstorms west of the center were producing upper level divergence which was pumping away mass to the west of the tropical cyclone.

Tropical Cyclone 02B will be moving through an environment that will be favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of the tropical cyclone is generating southeasterly winds which are blowing toward the top of the circulation.  Those winds are creating moderate vertical wind shear and the shear may be the reason why the thunderstorms were developing west of the center.  The shear will be strong enough to slow intensification, but it will not prevent intensification.  Tropical Cyclone 02B will intensify during the next two days and it could become the equivalent of a hurricane/typhoon.

A subtropical ridge located east of Tropical Cyclone 02B is steering it slowly toward the north-northeast.  A general north-northeasterly motion is expected to continue during the next several days.  On its anticipated track the center of Tropical Cyclone 02B could approach the coast of Bangladesh and northwestern Burma in about 48 hours.  Tropical Cyclone 02B could be the equivalent of a hurricane/typhoon by that time.  It could bring gusty winds and locally heavy rain when it makes landfall.  Heavy rain could cause fresh water flooding of rivers.  In addition the winds on the eastern side of Tropical Cyclone 02B will push water in the Bay of Bengal toward the coast.  A serious storm surge could occur along the coast east and near where the center makes landfall.

Possible Tropical Cyclone Developing Over Bay of Bengal

Satellite imagery indicates that a possible tropical cyclone may be developing over the Bay of Bengal.  Thunderstorms have increased and the system has been designated as Invest 94B.  At 8:00 p.m. EDT on Thursday the center of Invest 94B was located at latitude 11.8°N and longitude 88.7°E which put it about 575 miles (930 km) east of Chennai, India.  The invest was not moving much.  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1002 mb.

A circulation began to consolidate in an area of thunderstorms over the Bay of Bengal on Thursday.  Many more thunderstorms formed in the western half of the circulation.  Although there was still not a well defined center of circulation, some curved bands began to form.  A broad cyclonic circulation began to rotate counterclockwise.

Invest 94B was organizing in area that was favorable for further intensification.  It was moving over water where the Sea Surface Temperature was near 30°C.  An upper level ridge centered to the east of the invest was generating easterly winds that were blowing toward the top of the circulation.  The winds were producing some vertical wind shear and the shear may have contributed to the asymmetrical distribution of thunderstorms.  The shear could slow the development, but it is probably not strong enough to prevent the formation of a tropical cyclone.

Invest 94B did not move much during Thursday.  The is some uncertainty about the future track of the system.  Some numerical models are forecasting that the subtropical ridge to the east of Invest 94B will steer it toward the northern Bay of Bengal.

 

Tropical Cyclone Frances Intensifies Into Equivalent of a Hurricane

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon on Friday as it moved northwest of Australia.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Frances was located at latitude 12.6°S and longitude 124.1°E which put it about 200 miles (325 km) north of Kuri Bay, Australia.  Frances was moving toward the west-southwest at 9 m.p.h. (14 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 981 mb.

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon when it moved through a favorable environment.  Frances moved over water where the Sea Surface Temperature (SST) was near 30°C and the upper level winds were weak.  A primary rainband wrapped almost entirely around the center of circulation and an eyelike feature seemed to be indicated on some satellite imagery.  Thunderstorms around the eye generated upper level divergence which pumped out mass and the circulation assumed a more symmetrical circulation.  Other bands of showers and thunderstorms formed in the outer portions of the circulation.

Tropical Cyclone Frances may have reached its peak intensity.  Frances will continue to move over water where the SST is near 30°C.  However, it is about to move near the western end of an upper level ridge where there are stronger northerly winds.  Those stronger winds will create much more vertical wind shear and Tropical Cyclone Frances is likely to weaken during the next several days.

A subtropical ridge to the east of Frances is steering the tropical cyclone toward the west-southwest and that general motion is forecast to continue for the next several days.  On its anticipated track Tropical Cyclone Frances poses no threat to Western Australia, although it could cause increased wave action along the coast.

Tropical Cyclone Frances Develops North of Western Australia

An area of low pressure northwest of Western Australia developed into Tropical Cyclone Frances on Thursday.  At 10:00 a.m. EDT on Thursday the center of Tropical Cyclone Frances was located at latitude 11.0°S and longitude 128.3°E which put it about 255 miles (410 km) north-northeast of Kalumburu, Australia.  Frances was moving toward the west-southwest 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. (110 km/h).  The minimum surface pressure was 997 mb.

The organization of Tropical Cyclone Frances improved significantly during the past 24 hours.  A well organized center of circulation developed at the surface.  A primary rainband wrapped about two-thirds of the way around the southern and western sides of the center.  Additional bands of showers and thunderstorms formed in the outer portions of the circulation.  Thunderstorms near the core of the circulation generated upper level divergence which was pumping mass away to the south of the tropical cyclone.  Frances is a fairly small tropical cyclone and winds to tropical storm force only extend out about 100 miles (160 km) from the center.

Tropical Cyclone Frances will move through an environment that will be favorable for intensification during the next 24 to 36 hours.  Frances will move over water where the Sea Surface Temperature is near 30°C while is moves across the Timor Sea.  An upper level ridge east of Tropical Cyclone Frances is producing northeasterly winds which are blowing toward the top of the circulation.  Vertical wind shear may be the reason that the primary rainband wrapped around the southern and western sides of the center.  However, the vertical shear does not appear to be strong enough to significantly affect the upper level divergence.  Frances is likely to intensify during the next day or so.  Eventually, Tropical Cyclone Frances will move into an area where there are strong upper level northwesterly winds.  A significant increase in vertical wind shear should weaken Frances when that occurs.

A subtropical ridge to the east of Frances is steering the tropical cyclone toward the west-southwest.  A general motion toward the west-southwest is expected to continue during the next few days.  On its anticipated track the center of Tropical Cyclone Frances is forecast to stay north of the coast of Western Australia.  However, any southward deviation of the track could bring stronger winds closer to the coast.

Tropical Cyclone Maarutha Strengthens Over Bay of Bengal

Tropical Cyclone Maarutha strengthened over the Bay of Bengal on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Maarutha was located at latitude 15.8°N and longitude 91.7°E which put it about 350 miles (565 km) southwest of Sandoway, Burma.  Maarutha was moving toward the northeast at 18 m.p.h. (29 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 993 mb.

A primary rainband wrapped around the western side of the center of circulation.  The band was broken on the eastern side of the center.  Additional bands of showers and thunderstorms were revolving around the northern and eastern periphery of the circulation.  Thunderstorms in the primary rainband were generating upper level divergence which was pumping mass out to the northeast of the circulation.

Tropical Cyclone Maarutha will be moving through an environment that will be moderately favorable for intensification during the next 12-24 hours.  Maarutha will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge east of Maarutha is producing southwesterly winds which are blowing toward the top of the tropical cyclone.  Those winds are causing moderate vertical wind shear which will inhibit intensification.  Despite the vertical wind shear Tropical Cyclone Maarutha could intensify further before it makes landfall in Burma in 18 to 24 hours.

A subtropical ridge east of Maarutha is steering the tropical cyclone toward the northeast and that general motion is expected to continue for the next several days.  On its anticipated track Tropical Cyclone Maarutha will make landfall in Burma between Sittwe and Bassein near Sandoway.

Tropical Cyclone Maarutha will bring gusty winds and locally heavy rain to Burma when it makes landfall.  Some storm surge is likely south of where the center makes landfall and the wind blows the water toward the coast.

Tropical Cyclone Ernie Rapidly Intensifies Into the Equivalent of a Hurricane

The circulation of Tropical Cyclone Ernie rapidly intensified into the equivalent of a hurricane/typhoon late on Thursday.  At 8:00 p.m. EDT on Thursday the center of Tropical Cyclone Ernie was located at latitude 14.9°S and longitude 110.5°E which put it about 540 miles (870 km) north-northwest of Exmouth, Australia.  Ernie was moving toward the south-southwest at 8 m.p.h. (12 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 987 mb.

An area of thunderstorms just west of the center of circulation quickly wrapped around the entire center.  A clear eye formed at the center of circulation.  Additional bands of storms formed and were revolving around the core of the circulation.  Thunderstorms around the eye were generating strong upper level divergence which pumped out mass and allowed the surface pressure to decrease quickly.  The circulation of Tropical Cyclone Ernie is small and winds to tropical storm force extend out only about 90 miles (150 km) from the center of circulation.

Tropical Cyclone Ernie will remain in a very favorable environment for another 12 to 24 hours.  Ernie will be over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge southeast of Ernie is producing northerly winds near the tropical cyclone, but those winds are not creating significant wind shear.  Tropical Cyclone Ernie could strengthen further during the next day or so.  In a day or two Ernie will move into an environment of lower SSTs and more vertical wind shear.  Tropical Cyclone Ernie will weaken at that time.

A subtropical ridge southeast of Ernie is steering the tropical cyclone slowly toward the south-southwest.  The ridge is forecast to strengthen and extend westward.  When the ridge extends toward the west it will also steer Tropical Cyclone Ernie more toward the west.  On its anticipated track Tropical Cyclone Ernie poses no current threat to land.

Tropical Cyclone Ernie Forms Northwest of Australia

Tropical Cyclone Ernie formed northwest of Australia on Thursday.  At 2:00 p.m. EDT on Thursday the center of Tropical Cyclone Ernie was located at latitude 14.1°S and longitude 110.9°E which put it about 580 miles (940 km) north-northwest of Exmouth, Australia.  Ernie was moving toward the south-southwest at 5 m.p.h. (7 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. (100 km/h).  The minimum surface pressure was 995 mb.

Thunderstorms developed around a small area of low pressure south of Indonesia during the past several days.  The storms consolidated near the center of circulation on Thursday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Ernie.  Ernie does have a well organized low level center of circulation, but many of the thunderstorms are occurring just to the west of the center of circulation.  There are also several bands of showers and thunderstorms in the southeastern quadrant of the circulation.  The thunderstorms near the center are generating upper level divergence which is pumping out mass to the south and southeast of Tropical Cyclone Ernie.

Tropical Cyclone Ernie is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge southeast of Ernie is generating northerly winds which are cause some vertical wind shear over the tropical cyclone.  However, the vertical wind shear is not strong enough to prevent further intensification of Tropical Cyclone Ernie.  Ernie should intensify during the next 24 hours and it could intensify rapidly during that time.  Tropical Cyclone Ernie will move into an unfavorable environment in a day or two.  Ernie will move over cooler SSTs and into a region where stronger upper level winds will produce more vertical wind shear.  The tropical cyclone will weaken at that time.

A subtropical ridge centered southeast of Ernie is steering the tropical cyclone slowly toward the south-southwest.  The ridge is forecast to strengthen and extend farther to the west.  When the ridge extends westward, it will steer Tropical Cyclone Ernie more toward the west.  On its anticipated track Tropical Cyclone Ernie currently poses no threat to land.

Tropical Cyclone Caleb Forms Over South Indian Ocean

Tropical Cyclone Caleb formed over the South Indian Ocean on Thursday.  At 8:00 a.m. EDT on Thursday the center of Tropical Cyclone Caleb was located at latitude 13.0°S and longitude 100.7°E which put it about 255 miles (410 km) east-southeast of Cocos Island.  Caleb was moving toward the south-southeast at 6 m.p.h. (9 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 995 mb.

Although there is a well defined low level circulation in Tropical Cyclone Caleb, the distribution of thunderstorms is asymmetrical.  The strongest thunderstorms are occurring in the northwestern quadrant of the circulation and they are in the primary rainband.  Those thunderstorms contain the strongest winds.  There are few thunderstorms in the other parts of the circulation, although there are some bands of lower clouds and showers in those regions.  The thunderstorms in the primary rainband are generating upper level divergence which is pumping out mass to the west of Tropical Cyclone Caleb.

Tropical Cyclone Caleb is in an environment that is marginal for intensification.  Caleb is moving over water where the Sea Surface Temperature is near 28°C.  So, there is enough energy in the upper ocean to support intensification.  However, an upper level ridge located southeast of Caleb is producing easterly winds which are blowing across the top of the tropical cyclone.  The easterly winds are generating moderate vertical wind shear and the shear is probably the reason why most of the thunderstorms are occurring in the northwestern quadrant of the circulation.  The moderate shear will inhibit intensification, but some strengthening may be possible if the upper level winds abate.

A ridge to the east of Caleb is steering the tropical cyclone toward the south-southeast and that general motion is expected to continue for another day or two.  Eventually, a second ridge is forecast to strengthen and steer Tropical Caleb back toward the northwest.