Bay of Bengal system could become cyclone; Tamil Nadu and Sri Lanka rain outlook

A low-pressure area over the Bay of Bengal could strengthen into a depression on November 15 and a cyclone on November 16, according to the India Meteorological Department's forecast issued on November 13. These are forecast possibilities, not confirmation that a cyclone has already formed.

The system formed over the southeast Bay of Bengal at about 5.30am on November 13 and remained in that region at 8.30am. It developed under the influence of an atmospheric circulation over the central Andaman Sea and the adjoining Andaman and Nicobar Islands.

The forecast expected a northwestward movement and development into a well-marked low-pressure area around November 14, followed by a depression in the same region on the morning of November 15. A further north-northwestward movement could bring strengthening into a cyclone over the central Bay of Bengal by the evening of November 16.

Tamil Nadu: the November 13-19 rain outlook

November 13 and 14: isolated light rain was forecast for the Western Ghats districts, northern coastal Tamil Nadu, Puducherry and Karaikal. Other parts of Tamil Nadu were expected to remain generally dry.

November 15: the Western Ghats districts and southern Tamil Nadu could receive isolated light to moderate rain. Isolated light rain was forecast for the northern coastal districts, Puducherry and Karaikal, with generally dry conditions elsewhere in the state.

November 16: isolated light to moderate rain was expected in the Western Ghats districts and southern Tamil Nadu. The rest of Tamil Nadu, Puducherry and Karaikal were forecast to be generally dry.

November 17 and 18: isolated moderate rain was forecast for Tenkasi, Thoothukudi, Tirunelveli and Kanyakumari districts. Other Western Ghats districts could see isolated light rain. Remaining parts of Tamil Nadu, Puducherry and Karaikal were expected to stay generally dry.

November 19: isolated light rain was forecast in the Western Ghats districts and southern Tamil Nadu. Generally dry weather was expected in other parts of the state and in Puducherry and Karaikal.

Chennai forecast

For November 13 and 14, Chennai and its suburbs were expected to have partly cloudy skies and a chance of light rain in a few areas. The forecast put maximum temperatures at about 32-33 degrees Celsius and minimum temperatures near 24 degrees.

Strong winds at sea

Winds of 40-50km/h, occasionally reaching 60km/h, were forecast over the Andaman Sea on November 13 and 14 and over the southeast Bay of Bengal from November 13 to 16.

For the southwest Bay of Bengal from November 15 to 17 and the central Bay of Bengal on November 16 and 17, the wind warning was 45-55km/h, occasionally reaching 65km/h.

Heavy-rain risk in Sri Lanka

Sri Lanka's Department of Meteorology said the system's movement could bring heavy rain to many parts of the island from November 14 to 16. Areas identified included Batticaloa, Ampara and Trincomalee in the Eastern Province, as well as the Northern, North Central and North Western provinces. There was also a warning of possible flash flooding in some places.

At the time of the forecast, the system was expected to move north near Sri Lanka's eastern coast rather than cross the island. That was the projected track, not a completed movement.

The preceding 24 hours

The preceding 24-hour summary recorded isolated rain in Tamil Nadu and dry conditions in Puducherry and Karaikal. Mambazhathuraiyar in Kanyakumari recorded the highest stated rainfall, 61.0mm.

Maximum temperatures showed no significant general change across Tamil Nadu, Puducherry and Karaikal during that period. A few places in Tamil Nadu were 2-3 degrees Celsius above normal; elsewhere in the state and in Puducherry and Karaikal, temperatures were near normal.