Chennai, Aug 12 : The Southwest monsoon, which has become vigorous over Tamil Nadu, is set to bring widespread scattered rainfall in many parts of the state until Wednesday.

The Regional Meteorological Centre (RMC), Chennai, has warned of heavy rainfall in some northern districts over the next two days.

According to the RMC, an upper-air cyclonic circulation over north coastal Andhra Pradesh and adjoining Telangana is likely to intensify the rain activity in northern parts of Tamil Nadu.

The system is expected to trigger light to moderate showers in a few places in north Tamil Nadu on Tuesday, while districts such as Tiruvallur and Ranipet may experience heavy spells.

On Wednesday, the weather pattern is forecast to extend to more districts, including Vellore and Tirupattur, which may also see heavy downpours.

Officials noted that with the monsoon gaining strength in neighbouring Kerala, Nilgiris district is also likely to witness heavy rainfall until Wednesday.

The wet spell is expected to persist across several parts of the State until the weekend.

The prevailing cloudy and rainy conditions kept most districts cooler than usual on Monday, with the maximum temperature in Chennai's Nungambakkam station recording 35.3 degrees Celsius, the highest in the state.

Several places, including Vellore, Mayiladuthurai, Coimbatore, Tiruvallur, Ranipet and Salem, received rainfall until 6 p.m. on Monday.

B. Amudha, Head (Additional in-charge) of the RMC, said a low-pressure area is likely to form over the northwest and west-central Bay of Bengal around Wednesday. This developing system could bring significant rainfall to Andhra Pradesh and adjoining states.

"Some districts in Tamil Nadu may receive heavy rain due to possible cloud banding around the system. We will have a clearer picture of the rainfall pattern once the low-pressure area consolidates," she added.

For Chennai, the RMC has forecast chances of evening showers triggered by thunderstorm activity. Light to moderate rainfall is expected in some areas of the city on Tuesday.

The recent spell of rain has boosted Tamil Nadu's seasonal rainfall to a 20 per cent surplus since the onset of the southwest monsoon on June 1, offering a positive sign for water availability in the coming months.

/IANS