A tropical cyclone could form over the Bay of Bengal east of Sri Lanka during the next 24 hours. A low pressure system over the southern Bay of Bengal was designated as Invest 90B on Monday. At 10:00 p.m. EST on Monday the center of the low pressure system was located at latitude 8.5°N and longitude 84.5°E which put it about 185 miles (300 km) east-northeast of Batticaloa, Sri Lanka. The low pressure system was moving toward the west at 8 m.p.h. (13 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.
The circulation around a low pressure system over the Bay of Bengal east of Sri Lanka strengthened on Monday. More thunderstorms formed near the center of the low pressure system and the inner end of a rainband wrapped partly around the center of circulation. More thunderstorms formed in bands revolving around the center. Storms near the center of circulation generated upper level divergence that pumped mass away to the west of the low pressure system.
The low pressure system will move through an environment favorable for the formation of a tropical cyclone during the next 24 hours. The low pressure system will move over over water where the Sea Surface Temperatures are near 27˚C. It will move under the western end of an upper level ridge centered over Southeast Asia. The ridge will produce southeasterly winds that will blow toward the top of the low pressure system. Those winds will cause vertical wind shear and the shear will inhibit somewhat the formation of a tropical cyclone. However, the wind shear may not be strong enough to prevent the low pressure system from strengthening into a tropical cyclone. Invest 90B could strengthen to a tropical cyclone during the next 24 hours.
The low pressure system will move south of a strong high pressure system over southern Asia. The high pressure system will steer the low pressure system toward the west-southwest. On its anticipated track the low pressure system could reach the east coast of Sri Lanka within 24 hours. The low pressure system will bring gusty winds and locally heavy rain to Sri Lanka. Heavy rain could cause flash floods in some locations.