Tropical Cyclone Phethai Forms Over Southwest Bay of Bengal

Tropical Cyclone Phethai formed over the southwest Bay of Bengal on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Phethai was located at latitude 11.1°N and longitude 84.5°E which put it about 480 miles (775 km) south-southeast of Visakhapatnam, India.  Phethai was moving toward the northwest at 5 m.p.h. (8 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.

More thunderstorms developed closer to the center of a low pressure system over the southwestern Bay of Bengal and the Indian Meteorological Department designated the system as Tropical Cyclone Phethai.  The distribution of thunderstorms was asymmetrical.  Most of the stronger thunderstorms were occurring northwest of the center of circulation.  There were fewer thunderstorms southeast of the center, although several bands of thunderstorms were developing on the eastern periphery of the circulation.  Storms northwest of the center were generating upper level divergence which was pumping mass away to the north of the tropical cyclone.

Tropical Cyclone Phethai will move through an environment somewhat favorable for intensification.  Phethai will move over water where the Sea Surface Temperature is near 27°C.  It will move around the eastern end of an upper level ridge over southeast Asia.  The ridge is already producing southeasterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear and the shear is the reason for the asymmetrical distribution of thunderstorms.  The wind shear will continue and it will inhibit the intensification of Tropical Cyclone Phethai.  Phethai could strengthen during the next 24 to 36 hours, but the rate of intensification is likely to be slow.

The ridge over southeast Asia will steer Tropical Cyclone Phethai north-northwest during the next several days.  On its anticipated track Phethai will move toward the east coast of India.  Tropical Cyclone Phethai could approach the coast near Visakhaptnam in about 48 hours.  Phethai will bring gusty winds but heavy rain and flooding will be greater risks.

Elsewhere, Tropical Cyclone 06S formed over the South Indian Ocean on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone 06S was located at latitude 9.1°S and longitude 91.2°E which put it about 1285 miles (2070 km) east of Diego Garcia.  It was moving toward the south-southeast at 3 m.p.h. (5 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.