Tag Archives: Tropical Cyclone 04B

Tropical Cyclone 04B Brings Rain to Southern India

Tropical Cyclone 04B brought rain to parts of southern India on Thursday. At 4:00 a.m. EST on Thursday the center of Tropical Cyclone 04B was located at latitude 13.1°N and longitude 80.6°W which put it about 30 miles (50 km) east of Chennai, India. The tropical cyclone was moving toward the west-northwest at 9 m.p.h. (14 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 1003 mb.

A low pressure system over the western Bay of Bengal strengthened on Thursday morning and the Joint Typhoon Warning Center designated the system as Tropical Cyclone 04B. The India Meteorological Department classified the system as a depression. The center of Tropical Cyclone 04B was located near Chennai, India. The strongest thunderstorms were occurring in bands west of the center of circulation and along the northern periphery of the tropical cyclone. Bands in other parts of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 40 miles (65 km/h) from the center of the tropical cyclone.

The center of Tropical Cyclone 04B will make landfall on the southern coast of India near Chennai in a few hours. The tropical cyclone will bring gusty winds to the northern coast of Tamil Nadu and the southern coast of Andhra Pradesh. Tropical Cyclone 04B will drop locally heavy rain over parts or northern Tamil Nadu, southern Andhra Pradesh and southern Karnataka as it moves inland. The tropical cyclone will weaken gradually after it moves inland over southern India.

Tropical Cyclone 04B Forms over Bay of Bengal

Tropical Cyclone 04B formed over the Bay of Bengal east of Sri Lanka. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Gati (03A) was located at latitude 9.9°N and longitude 83.0°E which put it about 210 miles (340 km) east-southeast of Puducherry India and about 200 miles (320 km) east of Jaffna, Sri Lanka. It was moving toward the west at 7 m.p.h. (11 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.

The circulation around a low pressure system east of Sri Lanka strengthened on Monday. More thunderstorms developed near the center of the low and the wind speeds increased. The distribution of thunderstorms around the low was asymmetrical. Most of the thunderstorms were occurring in bands in the western half of the circulation. Bands in the eastern half of the tropical cyclone consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence which pumped mass away to the west of the tropical cyclone.

Tropical Cyclone 04B will move through an environment that is mostly favorable for intensification during the next during the next 36 hours. It will move over water where the Sea Surface Temperature is near 29°C. The tropical cyclone will move under the southern side of an upper level ridge over the Bay of Bengal. The ridge will produce easterly winds which will blow toward the top of the circulation. Those winds will cause moderate vertical wind shear and they are probably the reason for the asymmetrical distribution of thunderstorms. The wind shear will slow the rate of intensification, but the shear will not be large enough to keep the tropical cyclone from strengthening. Tropical Cyclone 04B could intensify into the equivalent of a hurricane/typhoon with 36 hours.

Tropical Cyclone 04B will move south of a ridge of high pressure over the Bay of Bengal. The high will steer the tropical cyclone toward the west-northwest. On its anticipated track the center of Tropical Cyclone 04B will pass north of Sri Lanka in about 24 hours. The tropical cyclone will approach the coast of India near Puducherry in 36 hours. It could be the equivalent of a hurricane/typhoon when it reaches the southeast coast of India.

Tropical Cyclone 04B will drop locally heavy rain over northern Sri Lanka. It will bring strong winds and locally heavy rain to southern India later this week. Heavy rain could cause flash floods in some locations.

Elsewhere, Tropical Cyclone Gati weakened as it moved across northeastern Somalia toward the Gulf of Aden. At 4:00 p.m. EST on Monday the center of Tropical Cyclone Gati (03A) was located at latitude 11.9°N and longitude 47.5°E which put it about 45 miles (75 km) northwest of Maydh, Somalia. Gati was moving toward the west-northwest at 13 m.p.h. (20 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 04B Develops Over Northern Bay of Bengal

Tropical Cyclone 04B developed over the northern Bay of Bengal on Friday.  The circulation around an area of low pressure southeast of India strengthened on Friday and the Joint Typhoon Warning Center (JTWC) designated the system as Tropical Cyclone 04B.  Data from a scatterometer on a satellite indicated there were winds to 45 m.p.h. (75 km/h) in the western part of the circulation.  The Indian Meteorological Department was classifying the low pressure system as a depression and that was why it did not have a name.

At 4:00 p.m. EDT on Friday the center of Tropical Cyclone 04B was located at latitude 18.7°N and longitude 86.9°E which put it about 340 miles (550 km) southwest of Kolkata, India.  It was moving toward the north at 18 m.p.h. (29 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 994 mb.

Although there was a well defined low level center of circulation, the rest of the circulation of Tropical Cyclone 04B was not particularly well organized.  There were no strong thunderstorms near the center of circulation.  The stronger thunderstorms were occurring in a rainband 80 miles (130 km) northeast of the center of circulation.  Other bands revolving around the center consisted primarily of low clouds and showers.

Tropical Cyclone 04B is moving through an environment that is only marginally favorable for intensification.  It 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, but that is about the only factor favorable for intensification.  Tropical Cyclone 04B is moving underneath the western end of an upper level ridge.  The ridge is producing southeasterly winds which are blowing across the top of the circulation.  Those winds are also causing moderate vertical wind shear and the shear is probably the reason why the band of thunderstorms is displaced northeast of the center of circulation.  It also appears that the western side of the circulation of Tropical Cyclone 04B is also pulling some drier air from over India into the system.  Tropical Cyclone 04B is unlikely to intensify due to the effects of moderate wind shear and drier air.

The upper level ridge is steering Tropical Cyclone 04B toward the north.  On its anticipated track Tropical Cyclone 04B could make landfall near Kolkata in 24 to 30 hours.  The primary risk is locally heavy rain which could cause flooding.  The rain is likely to reach northeastern India a few hours before the center of circulation makes landfall.