CHENNAI: Heavy rain continued to lash several parts of Tamil Nadu on Saturday, as the Met office forecast a prolonged wet spell over the state under the influence of a likely low-pressure area expected to form over the southwest Bay of Bengal around May 11.
The Regional Meteorological Centre (RMC), Chennai, said widespread rainfall activity was triggered by an upper-air cyclonic circulation over the Gulf of Mannar and adjoining Sri Lanka, extending up to 5.8 km above mean sea level. A trough extending from the southeast Arabian Sea to Maharashtra across Karnataka is also aiding moisture incursion over peninsular India.
The state recorded widespread rainfall during the 24 hours ending at 8.30 am on Saturday, with southern districts receiving intense showers. Oothu in Tirunelveli district recorded the highest rainfall in Tamil Nadu at 168 mm, followed by Nalumukku with 160 mm, Kakkachi with 140 mm and Manjolai with 110 mm, all in Tirunelveli district.
Heavy downpour likely in coastal TN this week
Other major places that received significant rainfall included Ayikudi and Bodinaickanur with 90 mm each, Karuppanadhi Dam in Tenkasi with 80 mm, Kulasekarapattinam and Sattankulam in Thoothukudi with 70 mm each. Several places in Kanniyakumari, Sivaganga, Coimbatore and Thanjavur districts received between 40 mm and 50 mm of rainfall.
Rainfall activity persisted through Saturday evening, particularly over north coastal and delta districts. Between 8.30 am and 5.30 pm, Meenambakkam in Chennai recorded 41.8 mm of rainfall, followed by Tiruchy Airport with 29 mm, Cuddalore with 25 mm and Nungambakkam with 23.9 mm. Ooty received 18.2 mm, Karaikal 17 mm, Nagapattinam and Koradachery 15 mm each, and Tiruttani in Tiruvallur district 13 mm.
Automatic weather stations also recorded significant rainfall, including 39.5 mm at the Meenambakkam ISRO station, 28.5 mm at Thiruninravur, 25 mm in Chennai city and 23 mm at Kalavai in Ranipet district.
The IMD has forecast light to moderate rain at many places over south Tamil Nadu and at a few places over north Tamil Nadu, Puducherry and Karaikal on Sunday, accompanied by thunderstorms, lightning and gusty winds reaching 40-50 kmph at isolated places.
Heavy rain is likely at isolated places over Dindigul, Madurai, Theni, Tenkasi, Virudhunagar, Tirunelveli, Kanniyakumari, Sivaganga, Ramanathapuram and Thoothukudi districts on Sunday.
The weather department has warned that rainfall activity is likely to shift gradually towards the northern coastal districts by midweek. Heavy rain is forecast over Chennai and adjoining districts on May 13 and 14, while very heavy rainfall is likely over Villupuram, Cuddalore, Puducherry and Kallakurichi on May 14. Western districts such as Erode, Salem and the Nilgiris may receive very heavy rain on May 15.
The widespread cloud cover and persistent rainfall have also resulted in a marked dip in daytime temperatures across the state. According to observations recorded at 5.30 pm on Saturday, Tiruchy Airport recorded a maximum temperature of 28.3°C, nearly 9.8°C below normal, while Cuddalore recorded 26.8°C, about 9.2°C below normal. Puducherry was 8.7°C below normal at 27.3°C, Nagapattinam 6.8°C below normal at 28.8°C, Chennai Airport 6.4°C below normal at 31.2°C and Nungambakkam 5.4°C below normal at 31°C. Tiruttani recorded a sharp departure of 7.4°C below normal at 32.5°C.
The IMD said maximum temperatures are likely to remain 3°C to 4°C below normal over Tamil Nadu, Puducherry and Karaikal till May 13 due to sustained cloud cover and rainfall activity.