The wet spell over Tamil Nadu is likely to continue till May 17. While the season’s first low-pressure area has formed over the Bay of Bengal, the Regional Meteorological Centre has noted that it is monitoring the system for its impact over the State.

The RMC has predicted heavy rainfall in isolated parts of 10 districts, including Nilgiris, Tiruvarur, Pudukottai and Ramanathapuram, on May 15 and 16.

Chennai may experience another relatively mild summer day on Tuesday, with light rainfall in some areas and maximum temperatures expected to hover around 34-35 degrees Celsius.

Simmering heat may temporarily abate, and the maximum temperatures may stay near normal over Tamil Nadu, Puducherry and Karaikal areas till weekend.

Officials of the RMC said that Monday’s low pressure area over southwest Bay of Bengal off north Sri Lanka coast is likely to be more marked in 48 hours. Another trough of easterlies runs from this low pressure area to south Lakshadweep across south Tamil Nadu.

V.R. Durai, Director, Regional Weather Forecasting Centre, RMC, said the formation of a low pressure area during summer was not unusual. However, the weather system’s movement, as of now, is not favourable for widespread intense rainfall across the State.

Various factors, including changes in wind flow to southwesterlies during the onset phase of southwest monsoon would also influence performance of the seasonal weather systems. “We are monitoring the system’s movement for impact over the State. There will be more clarity once the low pressure area becomes more marked in 48 hours,” he said.

The cyclonic circulation associated with the low pressure area was one of the reasons for moderate rainfall in some places along the coast, including delta districts, this week. The trough of easterlies may also influence rainfall activity over south Tamil Nadu.

Wet weather since early May has pushed seasonal rainfall to an 11% surplus than average recorded since March 1. Parts of Ramanathapuram, Nagapattinam, and Coimbatore received rainfall till 6 p.m. on Monday as well.

Moisture incursion from the weather disturbances would keep the daytime temperatures under control. On Monday, Erode recorded 38 degrees Celsius, the hottest maximum temperature in Tamil Nadu. Chennai Nungambakkam and Meenambakkam recorded 34 degrees Celsius and 34.7 degrees Celsius, which was nearly four degrees Celsius below normal.