A north-south trough is likely to bring isolated rainfall and help keep temperatures largely in the normal range across Tamil Nadu on Friday. Day temperature in Tamil Nadu is expected to gradually rise from May 10.
The Southwest monsoon, which is expected to advance into south Andaman sea and southeast Bay of Bengal by May 13, may not have a direct impact over the State as of now, said officials of the Regional Meteorological Centre, Chennai.
Recurring thunderstorms, since early this month, have spared many parts of the State from a sharp rise in mercury level, which is typical during peak summer. The RMC has forecast that the maximum temperature may increase by 2-3 degrees Celsius from May 10 in a few pockets of the State.
There is a possibility of slightly enhanced rainfall in a few places in the State between May 12 and May 14. The prevailing trough may trigger thunderstorms in one or two places over the State, including Chennai, with gusty winds on Friday.
On Thursday too, the maximum temperature was close to normal or below-normal in most places. Erode recorded the day’s hottest temperature of 39.2 degrees Celsius in the State. Chennai’s Nungambakkam was among the places that recorded below average temperature of 35.3 degrees Celsius. Some places like Vellore and Mamallapuram received light rainfall.
B. Amudha, Head (additional in-charge), RMC, said the wind discontinuity, a weather phenomenon that is usual during April and May, influenced rainfall and drop in maximum temperature.
The onset of Southwest monsoon occurs through two branches — the Arabian sea that strikes Kerala coast and the Bay of Bengal. The department monitored the cloud band movement and possibility of advancement of monsoon. Temperature may dip and rainfall may increase in parts of Tamil Nadu during the onset phase in Kerala, she said.
Last year too, the Southwest monsoon had advanced into the Bay of Bengal branch around May 19-21 against its normal onset date of May 26, Ms. Amudha added.
Y.E.A. Raj, former deputy director general of meteorology, Chennai, said the extended range prediction does not indicate early monsoon arrival over Kerala. There have been occasions in the past when heat had subsided over Tamil Nadu during early onset of Southwest monsoon by May last week.
The multi-model ensemble rainfall anomaly forecast indicated rainfall activity over Arabian sea between May 26 and June 1. The day temperature is likely to be below-normal over most parts of Tamil Nadu this month, he said.
Published – May 09, 2025 01:16 am IST