Two weather systems brewing in Bay of Bengal; Cyclone likely, says IMD

Amid the ongoing Northeast monsoon, two weather systems are brewing in the Bay of Bengal, off India's southeast coast. One of them is a well-marked low-pressure area adjoining the Andaman Sea, and this system is likely to move west-northwestwards and concentrate into a depression over the South Andaman Sea by Tuesday, (25th Nov). In addition to this, a low-pressure area is likely to form between the Indian mainland's southernmost tip and Sri Lanka, around Tuesday, and intensify thereafter, warned the Indian Meteorological Department(IMD).

In meteorology, a low-pressure area is one where the atmospheric pressure is lower than the surrounding areas. It is associated with cloud formation, increased, humidity and rainfall. It causes moderate rain, cloudy skies. If multiple factors are favourable, a low-pressure area could gradually intensify in a phased manner into a depression and later into a cyclonic storm.

Rainfall data shared on Monday (23rd Nov), showed that two locations in Tirunelveli district in Southern Tamil Nadu recorded over 22 cms of rainfall over the last 24 hours. Over 20 cm of rainfall in 24 hours is categorised as extremely heavy rainfall. Dozens of locations along coastal Tamil Nadu recorded over 11 cm of rainfall over the same period.

Owing to the two weather systems that are evolving in the Bay of Bengal, an alert for heavy rain has been issued for multiple districts across coastal Tamil Nadu through this week. Heavy to very heavy rainfall has been forecast for Chennai and adjoining districts on Saturday, (29th Nov), followed by heavy rain on Sunday.

Owing to rough sea conditions and gusty winds, fishermen have been warned against venturing out to sea along the Tamil Nadu coast through this week. Wind speeds are expected to touch 65kmph along parts of the Tamil Nadu coast, warned the IMD.