With the southwest monsoon gaining momentum over the southern peninsular region, the Regional Meteorological Centre has declared a red alert for Nilgiris district, indicating the possibility of extremely heavy rainfall in isolated places on Saturday and Sunday.

The prevailing upper air circulation over the southern peninsular region and the strong monsoon current would trigger heavy rainfall over Western Ghats districts and a few adjoining districts, said RMC officials.

The Meteorological Department has warned about the extreme weather-related impact over the Western Ghats areas such as waterlogging, road blockages and landslides or mudslides that are likely in hilly areas.

In its bulletin, the RMC has predicted scattered rainfall over Tamil Nadu and Puducherry till June 18. One or two places in Nilgiris district may receive extremely heavy rainfall above 20 cm on Saturday and Sunday. On Saturday, the ghat areas of Coimbatore and Tirunelveli district and Tenkasi and Kanniyakumari are likely to get rainfall up to very heavy intensity. Theni and Dindigul districts have been issued with yellow alert, indicating heavy rainfall.

While the similar pattern of heavy rain may continue on Sunday, some more districts like Tiruppur, Dindigul, Madurai and Virudhunagar are likely to get heavy rainfall. Heavy downpour is likely to batter Western Ghats districts, including Coimbatore, Nilgiris, Theni and Tenkasi until June 18.

P. Senthamarai Kannan, Director, Area Cyclone Warning Centre, RMC, said the monsoon that is in its active phase over southern peninsular region would enhance intense rainfall over Western Ghats areas and some interior districts. Chennai too may continue to experience evening thunderstorms in some areas on Saturday.

During the past 24 hours ending 8.30 a.m. on Friday, Nerkundram in Chennai recorded the heaviest rainfall of 17 cm in the State followed by Manali New Town with 14 cm. Mr. Kannan said the upper air circulation that was over south Andhra Pradesh on Thursday triggered heavy rainfall over city’s suburban areas and neighbouring districts before moving westwards. Heavy rainfall warning was given to districts, including Tiruvallur and Kancheepuram, on June 11.

On Friday, places like Dharmapuri, Valparai, and Coimbatore received 2 cm of rainfall between 8.30 a.m. and 5.30 p.m. Districts like Tirupattur and Krishnagiri too recorded light rainfall. The State has so far registered a normal seasonal rainfall since June 1 and some districts like Chennai, Cuddalore and Mayiladuthurai have recorded excess seasonal rainfall.