A Tropical Depression (also designated as Invest 98B) formed over the southern Bay of Bengal east of Sri Lanka on Monday. At 10:00 p.m. EST on Monday the center of a tropical depression was located at latitude 6.7°N and longitude 86.3°E which put it about 295 miles (475 km) east of Pottuvil, Sri Lanka. It was moving toward the west at 7 m.p.h. (11 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 1004 mb.

A low level center of circulation developed in an area of thunderstorms over the southern Bay of Bengal east of Sri Lanka on Monday. The circulation around the tropical depression was still organizing on Monday night. More thunderstorms were developing near the low level center. Bands of showers and thunderstorms were forming outside the center of circulation. Storms near the center started to generate upper level divergence which pumped mass away to the north and west of the tropical depression.

The tropical depression will move through a region somewhat favorable for intensification during the next 24 hours. The depression will move over water where the Sea Surface Temperature is near 29°C. It will move under the western end of an upper level ridge centered over Southeast Asia. The ridge will produce easterly winds which will blow toward the top of the depression. Those winds will cause moderate vertical wind shear. The shear will inhibit intensification, but it probably will not be strong enough to prevent the tropical depression from intensifying.

The tropical depression will move south of a high pressure system over India and the Bay of Bengal. The high will steer the depression toward the west during the next several days. On its anticipated track the tropical depression will approach Sri Lanka in about 36 hours. It will drop heavy rain over parts of Sri Lanka and flash floods could occur.