Tag Archives: Tropical Cyclone 01B

Tropical Cyclone 01B Weakens over Bay of Bengal

Tropical Cyclone 01B weakened over the Bay of Bengal on Saturday. At 4:00 p.m. EST on Saturday the center of Tropical Cyclone 01B was located at latitude 11.2°N and longitude 82.8°E which put it about 160 miles (260 km) east-southeast of Chennai India. It 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 1003 mb.

Tropical Cyclone 01B weakened over the southwest Bay of Bengal on Saturday. The inflow around the western side of the tropical cyclone pulled drier air that was over India into Tropical Cyclone 01B. The drier air circulated around the tropical cyclone and it caused many of the thunderstorms to dissipate. A few thunderstorms persisted in a band northeast of the center of circulation. The other bands consisted primarily of showers and lower clouds. The dissipation of thunderstorms resulted in a circulation that was present only in the lower atmosphere.

Tropical Cyclone 01B will move through an environment unfavorable for intensification during the next 24 hours. The tropical cyclone will move over water where the Sea Surface Temperatures are near 28˚C. However the drier air will continue to inhibit the formation of new thunderstorms. The tropical cyclone will move under the western part of an upper level ridge centered over southeast Asia. The ridge will produce southeast winds that will blow toward the top of the depression. Those winds will cause moderate vertical wind shear and the shear will also inhibit intensification. Tropical Cyclone 01B is likely to continue to weaken as the circulation spins down. It could bring rain showers to southern India early next week.

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.