Chennai: A low-pressure formation over the Kanyakumari Sea has strengthened and is moving towards Chennai and northern districts, the Regional Meteorological Centre (RMC) said on Thursday.

Several parts of southern Tamil Nadu recorded moderate rainfall in the 24 hours ending Wednesday morning. Pamban in Ramanathapuram district received the highest rainfall at 8 cm, followed by Rameswaram with 6 cm, Mandapam with 5 cm, Thangachimadam with 4 cm and Valinokkam with 2 cm.

The system over the Kanyakumari Sea and the adjoining southwest Bay of Bengal–Sri Lanka region has intensified into a well-marked low-pressure area. It is expected to track north-northwest and further develop into a depression before heading towards Chennai, the northern coastal districts and Puducherry.

The RMC also noted a second circulation near the Andaman Sea, close to the Malacca Strait, which intensified into a severe storm around 5.30 am on Thursday before moving west-southwest and crossing the Indonesian coast. Although this system is unlikely to directly impact Tamil Nadu, associated weather activity is expected to contribute to rainfall across the State.

Tamil Nadu and Puducherry are likely to experience moderate rain today, accompanied by thunderstorms and strong winds in several areas. Heavy rainfall is expected in parts of Ramanathapuram, Pudukottai, Thanjavur, Tiruvarur and Nagapattinam.

An orange alert has been issued for Ramanathapuram, Thanjavur, Tiruvarur, Nagapattinam and Karaikal for Thursday, with the RMC warning of very heavy rain. For Friday, heavy rain may affect Ramanathapuram, Sivaganga, Pudukottai, Mayiladuthurai, Cuddalore and Ariyalur.

A red alert has been issued for Tiruvarur, Nagapattinam, Mayiladuthurai, Cuddalore, Villupuram, Chengalpattu, Puducherry and Karaikal for Thursday and Friday, indicating the likelihood of extremely heavy rain in isolated locations. Chennai, Tiruvallur, Kancheepuram, Ranipet, Tiruvannamalai, Kallakurichi, Ariyalur, Perambalur and Thanjavur districts are under orange alert during the same period.

On Friday, heavy rain is also forecast for Pudukottai, Tiruchirappalli, Tirupattur, Vellore, Dharmapuri and Salem. The sky over Chennai is expected to remain partly cloudy today, with light showers possible in some areas.

Fishermen have been advised not to venture into the sea, as squally winds are likely along coastal Tamil Nadu, the Gulf of Mannar and the Kanyakumari Sea due to the evolving weather systems.

IANS