The prevailing upper-air circulation over the southeast Bay of Bengal is expected to bring scattered rainfall and thunderstorms across Tamil Nadu, helping to moderate temperatures until May 20, 2025.
The Regional Meteorological Centre (RMC), Chennai, has forecast that intense rainfall in parts of the delta and interior districts of the State on Saturday (May 17) would move to north Tamil Nadu districts like Tirupattur and Vellore on Sunday (May 18). Isolated heavy rainfall would cover Western Ghats and interior districts on Monday (May 19) and be limited to Ghat districts on May 20 and then May 23.
The advancing Southwest monsoon and its clouding and the upper-air circulation were cited as factors that influenced the rainfall episodes. Many parts of the State may be spared from the searing heat as the RMC has forecast an overall dip in day temperatures even up to four degree Celsius in a few pockets till May 21.
In its bulletin, the RMC has said conditions are favourable for Southwest monsoon to further advance into more parts of Arabian sea, Maldives, Comorin area, and Bay of Bengal in the next three or four days.
On Saturday, Chengam in Tiruvannamalai district recorded the heaviest of 10 cm of rainfall. This was among the many places in north Tamil Nadu that received rainfall.
B. Amudha, Head (Additional in-charge), RMC, said the monsoon clouding progressing over Bay of Bengal and Arabian Sea and prevailing weather system are among many factors that trigger rainfall activity over the State.
“Upper air cyclonic circulations over Tamil Nadu and adjoining sea areas usually will trigger rainfall episodes as moisture will be dragged into the land areas when winds are favourable,” she said.
The RMC has also warned fishermen not to venture into the sea as squally wind with speed gusting up to 55 kmph is likely over south Tamil Nadu coast, Gulf of Mannar, and adjoining Comorin area till May 21.
Published – May 17, 2025 06:00 pm IST