After receiving a record rainfall in 24 hours till Sunday, Chennai will experience thunderstorms and heavy rain in the next 48 hours. Thunderstorms with lightning may occur in many other parts of Tamil Nadu, too, for two more days.
From October 1 to November 7, Chennai received 26% surplus rain and the State got 43% more than the usual amount, said S. Balachandran, Deputy Director-General of Meteorology, Regional Meteorological Centre. In this period, Chennai recorded 48 cm as against the normal 38 cm. Tamil Nadu got 33 cm as against 23 cm. “Chennai received very heavy rain in a very short span of time. Till 10 p.m. [Saturday], the city received only 3 cm of rain, but from 1 a.m. to 1.45 a.m., there was 6 cm and from 5 a.m. to 6 a.m., another 7 cm. This is called mesoscale phenomena, which are difficult to predict,” he said.
The sudden rain occurred because of a cyclonic circulation over the south-east Bay of Bengal and the adjoining equatorial Indian Ocean extending up to 4.5 km above the mean sea level. A low-pressure area may form over the south-east Bay of Bengal and surrounding areas by November 9, according to the India Meteorological Department (IMD). This could become more pronounced and move in the direction of north Tamil Nadu coast in the next 48 hours.
On November 10 and 11, districts in north coastal Tamil Nadu may receive scattered heavy to very heavy rainfall. A few areas are also expected to get extremely heavy rainfall. Interior parts of the State may get heavy rain. “Heavy to very heavy rain is likely to occur at isolated places over the Nilgiris, Coimbatore, Erode and Krishnagiri districts of Tamil Nadu, and Kerala. Heavy rain is also likely to occur at isolated places over Madurai, Virudhunagar and the Cauvery delta districts of Tamil Nadu and south interior Karnataka,” the IMD said.
The weather station at the DGP office received 23 cm for a 24-hour period ending 8.30 a.m. on Sunday. This was followed by Nungambakkam and Ambattur, each getting 21 cm. While Ayanavaram got 18 cm, MGR Nagar received 17 cm. There was 16 cm and 15 cm of rainfall at Anna University and Puzhal respectively.
Sirugamani in Tiruchi district received 12 cm of rain. Tiruvadanai in Ramanathapuram district; Cholavaram in Tiruvallur district; Viralimalai in Pudukottai district; Valinokkam in Ramanathapuram district; Mohanur in Namakkal district; Musiri in Tiruchi district; Gummidipoondi in Tiruvallur district; Peravurani in Thanjavur district; and Madurai South received 9 cm each.